CN112087166B - Alternating current-direct current hybrid double-fed asynchronous full-electric ship electric propulsion system and control method - Google Patents

Abstract

The invention discloses an alternating current-direct current hybrid double-fed asynchronous full-electric ship electric propulsion system and a control method, and belongs to the field of motors. The propulsion system of the invention respectively carries out electric energy transmission through the electric energy transmission passages based on the alternating current transmission line and the back-to-back power electronic converter, can flexibly adjust the proportion of alternating current-direct current transmission according to the capacity of the power electronic converter and the ship operation mode, has smaller capacity required by the power electronic converter, and reduces the dependence of the system reliability and safety on power electronic equipment; the back-to-back power electronic converter is only responsible for processing a small part of the total energy, and the direct current transmission and distribution of the whole all-electric ship electric propulsion system only aims at the part of the energy, so that the proportion of the direct current transmission and distribution electronic system in the whole all-electric ship electric propulsion system is obviously reduced, the fault protection requirement is greatly reduced, the use of expensive direct current circuit breakers with immature technology is reduced, and the cost of system fault protection is reduced.

Description

AC-DC hybrid doubly-fed asynchronous all-electric marine electric propulsion system and control method

technical field

The invention belongs to the technical field of motors and systems thereof, and more particularly relates to an AC-DC hybrid doubly-fed asynchronous all-electric marine electric propulsion system and a control method.

Background technique

The development of the shipbuilding industry has an important impact on global transportation and the world economy, and the related technologies of large ships have also received considerable attention in the military field, which is an important manifestation of the country's military strength. In order to meet the ever-increasing demand for ship electricity, all-electric ships based on electric propulsion systems have gradually become the ship production standard for large shipyards in the world, which is also the development direction of ships in the future. With the rapid development of modern power electronics technology, control theory and other related technologies, "medium-voltage DC integrated marine electric propulsion system" is becoming a research hotspot in the field of all-electric ships today.

The electric energy conversion and transmission in the MV DC integrated marine electric propulsion system completely relies on the power electronic converter and the DC bus. On the one hand, the power electronic devices in the converter are made of relatively fragile semiconductor materials, which are more vulnerable to damage than other components in the system, posing a potential threat to the system security; on the other hand, in the power system architecture based on the DC bus The current is not zero, so the fault current does not have the ability to self-extinguishing. If the faulty part cannot be removed quickly and accurately, the operation of other equipment in the ship's electric propulsion system will also be seriously affected, which puts forward extremely high requirements for fault protection and requires huge investment.

SUMMARY OF THE INVENTION

In view of the above defects or improvement needs of the prior art, the present invention provides an AC-DC hybrid doubly-fed asynchronous all-electric marine electric propulsion system and a control method, the purpose of which is to solve the power electronic conversion in the medium-voltage DC integrated marine electric propulsion system. The fragility of the inverter and the high fault protection requirements and high cost of the energy transmission system based on the medium voltage DC bus.

In order to achieve the above object, according to one aspect of the present invention, an AC-DC hybrid doubly-fed asynchronous all-electric marine electric propulsion system is provided, comprising: a power generation unit, a back-to-back power electronic converter and a doubly-fed asynchronous motor;

Power generation unit, which is used to provide electrical energy for all-electric ships;

The power generation unit and the doubly-fed asynchronous motor are connected through two parallel energy paths: one of them is directly connected to the stator of the doubly-fed asynchronous motor through an AC transmission line to form the main energy path; After DC-AC conversion, it is connected to the rotor of the doubly-fed asynchronous motor to form a slip energy path;

Among them, the main energy path is used to directly input more than 50% of the output energy of the power generation unit into the doubly-fed asynchronous motor; the slip energy path is used to input the remaining energy output by the power generation unit into the doubly-fed asynchronous motor, and through the back-to-back power electronics The converter controls the normal operation of the doubly-fed asynchronous motor;

Doubly-fed asynchronous motors for powering the operation of all-electric vessels.

Further, the power generation unit includes a prime mover, a synchronous generator, an excitation control module, and a speed regulation module;

The prime mover drives the synchronous generator to rotate by converting chemical energy into mechanical energy; the excitation control module is used to generate the excitation voltage signal; the synchronous generator generates a three-phase AC voltage on the stator side of the generator according to the excitation voltage signal generated by the excitation control module , to provide electrical energy for the whole ship, and also input as a feedback signal to the excitation control module; the speed control module is used to issue power commands to the prime mover to control the operation of the prime mover, thereby controlling the rotational speed of the synchronous generator.

Further, the back-to-back power electronic converter includes a power-side converter and a load-side converter;

The power-side converter is used to control the DC bus voltage and three-phase current, so that the DC bus voltage is kept constant, and a sinusoidal three-phase current is obtained; the load-side converter is used to control the rotational speed and power of the doubly-fed asynchronous motor to achieve Real-time tracking of power to load power changes, maintaining energy balance between input and output; the input power is generated by a synchronous generator; the load refers to a double-fed asynchronous motor.

Further, the positive direction of the d-axis in the dq model of the synchronous generator is consistent with the direction of its rotor flux linkage.

According to a second aspect of the present invention, a method for controlling a doubly-fed asynchronous all-electric marine electric propulsion system based on stator voltage vector orientation is provided, comprising:

S1. For the stator voltage V _sabc , use the phase-locked loop to calculate the synchronous angular velocity ω _e and the synchronous electrical angle θ _e ;

S2. Use the synchronous electrical angle θ _e to perform abc-dq coordinate transformation on the stator voltage V _sabc , the stator current I _sabc , and the power-side converter current I _ssabc to obtain the dq stator voltage V _sdq , the dq stator current I _sdq , and the power-side converter dq current I _ssdq ;

S3. Input ω _e into the speed regulation module to control the rotational speed of the synchronous generator;

S4. DC bus voltage control and power-side converter current control:

Perform PI adjustment on the DC bus voltage difference to generate the d-axis current reference value I _ssd ^* of the power-side converter; set the q-axis current reference value I _ssq ^* of the power-side converter to 0; After the difference is adjusted by PI, the compensation items 1 and 2 are added respectively to obtain the dq reference voltage signal of the power-side converter, and the three-phase reference voltage signal of the power-side converter is obtained through Parker inverse transformation; the power-side converter is obtained through the pulse width modulation strategy. Each bridge arm switch signal S _ssabc of ; wherein,

In the formula, v _sd and v _sq are the d and q stator voltages of the doubly-fed asynchronous motor, respectively; R _ss represents the line resistance of the power-side converter, _issd and _issq represent the d and q currents of the power-side converter, respectively, and L _ss represents Line inductance of the power-side converter;

S5. Doubly-fed asynchronous motor speed control and load-side converter current control:

相除获得负载侧变换器d轴电流参考值I_rd ^*；将负载侧变换器q轴电流参考值I_rq ^*设置为0；对负载侧变换器的dq轴电流差值经PI调节后，分别加入补偿项3、4，获得负载侧变换器dq参考电压信号，通过派克反变换得到负载侧变换器三相参考电压信号；通过脉宽调制策略获得负载侧变换器的各桥臂开关信号S_lsabc；其中，定子磁链

在d、q轴坐标系下，根据dq定子电压V_sdq、dq定子电流I_sdq和同步角速度ω_e计算得到；PI adjustment is performed on the rotor angular velocity difference to obtain the electromagnetic torque reference value T _em ^* , which is related to the stator flux linkage

Divide to obtain the d-axis current reference value I _rd ^* of the load-side converter; set the q-axis current reference value I _rq ^* of the load-side converter to 0; after the dq-axis current difference of the load-side converter is adjusted by PI, respectively Add the compensation items 3 and 4 to obtain the dq reference voltage signal of the load-side converter, and obtain the three-phase reference voltage signal of the load-side converter through Parker inverse transformation; obtain the switching signal S _lsabc of each bridge arm of the load-side converter through the pulse width modulation strategy ; Among them, the stator flux linkage

In the d, q axis coordinate system, it is calculated according to the dq stator voltage V _sdq , the dq stator current I _sdq and the synchronous angular velocity ω _e ;

In the formula, R _r is the rotor resistance of the doubly-fed asynchronous motor, i _rd and i _rq are the rotor currents of the d- and q-axis of the doubly-fed asynchronous motor, respectively, ω _slip is the slip angular velocity, L _r is the rotor inductance, σ is the leakage flux coefficient, k _s is the stator coupling coefficient.

According to a third aspect of the present invention, a method for controlling a doubly-fed asynchronous all-electric marine electric propulsion system based on stator flux linkage vector orientation is provided, comprising:

根据

计算同步电角度θ_e；S1. Calculate stator flux linkage in α, β coordinate system

according to

Calculate the synchronous electrical angle θ _e ;

S2. Use the synchronous electrical angle θ _e to perform abc-dq coordinate transformation on the stator voltage V _sabc , the stator current I _sabc , and the power-side converter current I _ssabc to obtain the dq stator voltage V _sdq , the dq stator current I _sdq , and the power-side converter dq current I _ssdq ;

S3. Set the synchronous angular velocity ω _e to 1pu and input the speed regulation module to control the rotational speed of the synchronous generator;

S4. DC bus voltage control and power-side converter current control:

Perform PI adjustment on the DC bus voltage difference to generate the q-axis current reference value I _ssq ^* of the power-side converter; set the d-axis current reference value I _ssd ^* of the power-side converter to 0; After the difference is adjusted by PI, the compensation items 5 and 6 are respectively added to obtain the dq reference voltage signal, and the three-phase reference voltage signal is obtained through the inverse Parker transformation; the switching signal S _ssabc of each bridge arm of the power-side converter is obtained through the pulse width modulation strategy;

In the formula, v _sd and v _sq are the d and q stator voltages of the doubly-fed asynchronous motor, respectively, _issd and _issq represent the d and q currents on the converter side of the power supply side, respectively, and L _ss represents the line inductance of the converter on the power supply side;

S5. Doubly-fed asynchronous motor speed control and load-side converter current control:

相除获得负载侧变换器q轴电流参考值I_rq ^*；将负载侧变换器d轴电流参考值I_rd ^*设置为0；对负载侧变换器的dq轴电流差值经PI调节后，分别加入补偿项7、8来获得dq参考电压信号，并通过派克反变换得到三相参考电压信号，从而进一步通过脉宽调制策略获得负载侧变换器的各桥臂开关信号S_lsabc；PI adjustment is performed on the rotor angular velocity difference to obtain the electromagnetic torque reference value T _em ^* , which is related to the stator flux linkage

Divide to obtain the q-axis current reference value I _rq ^* of the load-side converter; set the d-axis current reference value I _rd ^* of the load-side converter to 0; after the dq-axis current difference of the load-side converter is adjusted by PI, respectively Add the compensation items 7 and 8 to obtain the dq reference voltage signal, and obtain the three-phase reference voltage signal through Parker inverse transformation, thereby further obtaining each bridge arm switching signal S _lsabc of the load-side converter through the pulse width modulation strategy;

Among them, ω _slip is the slip angular velocity, σ is the leakage flux coefficient, L _r is the rotor inductance, ks is the stator coupling coefficient, _{i rd} and i _rq are the d and q-axis rotor currents of the doubly-fed asynchronous motor, respectively.

According to a third aspect of the present invention, a method for controlling a doubly-fed asynchronous all-electric marine electric propulsion system based on analog stator voltage vector orientation is provided, comprising:

根据

计算磁链角

对磁链角

加上90°得到同步电角度θ_e；其中θ_e与模拟的定子电压矢量方向相同；S1. Calculate the stator flux linkage according to the stator voltage and current V _sαβ and I _sαβ in the two-phase stationary coordinate system

according to

Calculate the flux linkage angle

To flux angle

Add 90° to get the synchronous electrical angle θ _e ; where θ _e is in the same direction as the simulated stator voltage vector;

S2. Use the synchronous electrical angle θ _e to perform abc-dq coordinate transformation on the stator voltage V _sabc , the stator current I _sabc , and the power-side converter current I _ssabc to obtain the dq stator voltage V _sdq , the dq stator current I _sdq , and the power-side converter The actual value of the dq-axis current I _ssdq ;

S3. Set the synchronous angular velocity ω _e to 1pu and input the speed regulation module to control the rotational speed of the synchronous generator;

S4. DC bus voltage control and power-side converter current control:

The DC bus voltage difference is adjusted by PI to generate the d-axis current reference value I _ssd ^* of the power-side converter; the q-axis current reference value I _ssq ^* of the power-side converter is set to 0; the dq-axis current difference of the power-side converter is After the value is adjusted by PI, the dq reference voltage signal is obtained by adding compensation items 1 and 2 respectively, and the three-phase reference voltage signal is obtained through Parker inverse transformation; the switching signal S of each bridge arm of the power-side converter is obtained through the pulse width modulation strategy _ssabc ;

In the formula, v _sd and v _sq are the d and q stator voltages of the doubly-fed asynchronous motor, respectively; R _ss represents the line resistance of the power-side converter, _issd and _issq represent the d and q currents of the power-side converter, respectively, and L _ss represents Line inductance of the power-side converter;

S5. Doubly-fed asynchronous motor speed control and load-side converter current control:

相除获得负载侧变换器d轴电流参考值I_rd ^*；将负载侧变换器q轴电流参考值I_rq ^*设置为0；对负载侧变换器的dq轴电流差值经PI调节后，分别加入补偿项3、4，获得dq参考电压信号，并通过派克反变换得到三相参考电压信号；通过脉宽调制策略获得负载侧变换器的各桥臂开关信号S_lsabc；The electromagnetic torque reference value T _em ^* is obtained by adjusting the rotor angular velocity difference through PI, which is related to the stator flux linkage

Divide to obtain the d-axis current reference value I _rd ^* of the load-side converter; set the q-axis current reference value I _rq ^* of the load-side converter to 0; after the dq-axis current difference of the load-side converter is adjusted by PI, respectively Add the compensation items 3 and 4 to obtain the dq reference voltage signal, and obtain the three-phase reference voltage signal through Parker inverse transformation; obtain each bridge arm switch signal S _lsabc of the load-side converter through the pulse width modulation strategy;

In the formula, R _r is the rotor resistance of the doubly-fed asynchronous motor, i _rd and i _rq are the rotor currents of the d- and q-axis of the doubly-fed asynchronous motor, respectively, ω _slip is the slip angular velocity, L _r is the rotor inductance, σ is the leakage flux coefficient, k _s is the stator coupling coefficient.

In general, compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects.

(1) The all-electric ship power system based on the doubly-fed asynchronous propulsion motor proposed by the present invention transmits power through the power transmission path based on the AC power transmission line and the back-to-back power electronic converter, and can be flexibly based on the capacity of the power electronic converter and the ship's operation mode. By adjusting the ratio of AC and DC transmission, the power electronic converter of the system requires less capacity, which reduces the dependence of system reliability and safety on power electronic equipment.

(2) In the present invention, the back-to-back power electronic converter is only responsible for processing a small part of the total energy, and the DC transmission and distribution of the entire all-electric marine electric propulsion system is only for this part of the energy, so the DC transmission and distribution subsystem is used in the entire full The proportion of electric ship electric propulsion system has been significantly reduced, which greatly reduces its fault protection requirements, also reduces the use of expensive and immature technology DC circuit breakers, and reduces the cost of system fault protection.

Description of drawings

Figure 1 is a schematic structural diagram of an AC-DC hybrid doubly-fed asynchronous all-electric marine electric propulsion system;

Figure 2(a) is a d-axis equivalent circuit diagram of a salient-pole synchronous generator;

Figure 2(b) is a q-axis equivalent circuit diagram of a salient-pole synchronous generator;

Figure 2(c) is the control logic block diagram of the excitation control module;

Figure 3(a) is a d-axis equivalent circuit diagram of a doubly-fed asynchronous motor;

Figure 3(b) is the q-axis equivalent circuit diagram of the doubly-fed asynchronous motor;

Figure 3(c) is an equivalent circuit diagram of a detailed switching model of a back-to-back power electronic converter;

Figure 3(d) is the equivalent circuit diagram of the average controlled voltage source model of the back-to-back power electronic converter;

Figure 4 is a control block diagram of a doubly-fed asynchronous all-electric marine electric propulsion system based on phase-locked loop-based stator voltage vector orientation;

Fig. 5 is a control block diagram of a doubly-fed asynchronous all-electric marine electric propulsion system based on stator flux linkage estimation and flux linkage angle calculation based on stator flux linkage vector orientation;

Figure 6 is a control block diagram of a doubly-fed asynchronous all-electric marine electric propulsion system based on stator flux linkage estimation and flux linkage angle calculation simulating stator voltage vector orientation.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

The AC-DC hybrid all-electric marine electric propulsion system based on the doubly-fed asynchronous motor reduces the capacity of the power electronic converter and the DC bus by adopting the partial power decoupling system architecture of the AC-DC hybrid power distribution, thereby greatly reducing the power electronic The potential threat of converter vulnerability to system security reduces the difficulty and cost of system fault protection. Specifically, compared with the medium-voltage DC integrated electric propulsion system, the proposed all-electric marine power system based on the doubly-fed asynchronous propulsion motor transmits power through the power transmission paths based on the AC transmission line and the back-to-back power electronic converter, respectively. The power electronic converter capacity and the ship's operating mode can flexibly adjust the proportion of AC and DC transmission. The capacity of the back-to-back power converter corresponds to the ratio of the DC transmission system, and the larger capacity of the back-to-back power electronic converter means that a higher proportion of electrical energy is transmitted in the form of DC transmission. When the speed variation range of ship operation is small, the proportion of DC power transmission is correspondingly small, and the electrical energy of the ship's electric propulsion system is mainly transmitted in the form of AC power transmission; when the speed change range of ship operation is large, the proportion of DC power transmission is also correspondingly larger. This power system power electronic converter requires a small capacity, which reduces the dependence of system reliability and safety on power electronic equipment; the back-to-back power electronic converter is only responsible for processing a small part of the total energy, and the entire all-electric ship power The DC transmission and distribution of the propulsion system is only for this part of the energy, so the proportion of the DC transmission and distribution subsystem in the entire electric propulsion system of the all-electric ship has been significantly reduced, thereby greatly reducing its fault protection requirements, and reducing the cost and technical The use of immature DC circuit breakers reduces the cost of system fault protection.

As shown in FIG. 1 , the AC-DC hybrid doubly-fed asynchronous all-electric marine electric propulsion system provided by the embodiment of the present invention includes: a power generation unit, a back-to-back power electronic converter, and a doubly-fed asynchronous motor;

The doubly-fed asynchronous motor and the back-to-back power electronic converter together constitute the doubly-fed asynchronous power transmission subsystem in the system; the power generation unit is used to provide electric energy for the all-electric ship, and its output is three-phase AC voltage and power, and They are also the input of the doubly-fed asynchronous electric drive subsystem; the doubly-fed asynchronous motor, as the most important load of the all-electric ship, is responsible for providing power for the operation of the all-electric ship.

In the present invention, the power generation unit and the doubly-fed asynchronous motor are connected through two parallel energy paths: one is directly connected with the stator of the doubly-fed asynchronous motor through an AC transmission line to form the main energy path; After AC-DC-AC conversion, it is connected with the rotor of the doubly-fed asynchronous motor to form a slip energy path; among them, the main energy path is used to directly input more than 50% of the output energy of the power generation unit into the doubly-fed asynchronous motor; the slip energy path, Then it is used to input the residual energy output by the power generation unit into the double-fed asynchronous motor, and at the same time control the normal operation of the double-fed asynchronous motor through the back-to-back power electronic converter. Specifically, the energy transmitted by the main energy path is allocated according to the proportion of the back-to-back power electronic converter capacity to the capacity of the all-electric ship's power transmission system: for cruise ships, passenger ships, etc. The back-to-back power electronic converter requires a large capacity, so the energy directly input to the doubly-fed asynchronous motor through the AC transmission line is about 50%; The capacity of the back-to-back power electronic converter is relatively small, so the energy directly input to the doubly-fed asynchronous motor through the AC transmission line can reach 80%.

The back-to-back power electronic converter includes power-side and load-side converters for controlling the operation of the doubly-fed asynchronous motor; the power-side converter is used for controlling the DC bus voltage and three-phase current to maintain the DC bus voltage constant and obtain a sinusoidal The load-side converter is used to control the speed and power of the doubly-fed asynchronous motor, realize the real-time tracking of the input power to the load power change, and maintain the energy balance between the input and output terminals; the input power is generated from the synchronous generator; the load refers to the dual Feed asynchronous motor.

The power generation unit includes a synchronous generator, an excitation control module and a speed regulation module; the synchronous generator is driven by the prime mover, and generates an excitation voltage through the excitation control module, thereby generating a three-phase AC voltage on the generator stator side to provide electrical energy for the whole ship ; The three-phase voltage of the stator terminal of the synchronous generator is also used as the feedback signal of the input excitation control module; the speed regulation module is used to control the generator speed, and control the operation of the prime mover by issuing power commands to the prime mover, thereby controlling the generator speed. . The rotational speed control and excitation control of the synchronous generator are realized by inputting rotational speed and excitation voltage signals respectively.

The positive direction of the d-axis in the dq model of the synchronous generator in the present invention is consistent with the direction of the rotor flux linkage, so the d-axis of the rotor contains excitation and damping windings, while the q-axis only contains damping windings; as shown in Figure 2(a), in the convex The d-axis of the pole synchronous motor includes stator leakage inductance L _ld , rotor damping leakage inductance L _lkd , rotor excitation leakage inductance L _lfd , mutual inductance L _md , as well as stator resistance R _SG , rotor damping resistance R _kd , and rotor excitation resistance R _fd .

As shown in Figure 2(b), the q-axis of the salient-pole synchronous motor includes stator leakage inductance L _lq , rotor damping leakage inductance L _lkq , mutual inductance L _md , as well as stator resistance R _SG and rotor damping resistance R _kq . Therefore, the q-axis of the synchronous motor does not contain an excitation component.

The voltage and flux linkage equations for a synchronous generator can be expressed by the following equations:

分别为同步发电机d、q轴定子磁链；v_kd、v_kq分别为同步发电机d、q轴转子阻尼绕组端电压；i_kd、i_kq分别为同步发电机d、q轴转子阻尼绕组电流；

分别为同步发电机d、q轴转子阻尼绕组磁链；v_f、i_f、

分别为同步发电机转子励磁电压、电流和磁链；ω_SG为同步发电机角速度；p表示微分算子；v _d and v _q are the d and q-axis stator voltages of the synchronous generator, respectively; id and i _q are the _d and q-axis stator currents of the synchronous generator, respectively;

are the d and q-axis stator flux linkages of the synchronous generator, respectively; v _kd and v _kq are the terminal voltages of the d and q-axis rotor damping windings of the synchronous generator, respectively; i _kd and i _kq are the d and q-axis rotor damping windings of the synchronous generator, respectively current;

are the d and q-axis rotor damping winding flux linkages of the synchronous generator, respectively; v _f , _if ,

are the excitation voltage, current and flux linkage of the rotor of the synchronous generator, respectively; ω _SG is the angular velocity of the synchronous generator; p represents the differential operator;

The excitation control module includes voltage regulator, proportional saturation, exciter, damping filter and low-pass filter, as shown in Figure 2(c); the reference voltage _Vref and ground zero voltage _Vstab are used as the input of the excitation control module, Subtract the stator terminal voltage amplitude V _T and the excitation voltage feedback value V _f through the damping filter; the obtained voltage difference is controlled by the voltage regulator, and then the excitation voltage signal command is generated by the exciter, and finally the excitation voltage value is passed through the damping filter. feedback back to the input terminal after the device;

The rationality of setting the voltage regulator gain Ka, exciter gain _Ke , damping filter gain K _f , voltage regulator time constant T _a , exciter time constant _Te and damping filter time constant _{T f of} the excitation control module It directly affects the control stability of the power generation unit, and then affects the stable operation of the entire electric propulsion system; in addition, the setting of the upper and lower limits of the proportional saturation in the excitation control module also needs to be carefully considered. Specifically, according to the relationship between the input (stator voltage) and the output (excitation voltage) of the excitation control module, the transfer function (which includes the gain and time constant of the voltage regulator, exciter and damping filter control module, and parameters such as the upper and lower limits of the proportional saturation module), and analyze the stability of the excitation control module according to the transfer function, as long as the parameter settings can keep the excitation control module stable, it is reasonable.

Among them, the input voltage of the excitation control module is defined as follows:

Among them, V ^* represents the reference voltage, and V _f0 represents the initial value of the excitation voltage;

Therefore, the transfer function between the input voltage and the excitation voltage is

与

分别为定转子磁链，p为微分算子，ω_e为同步角速度，ω_r为转子电角速度；如图3(a)所示，电机定子侧d轴等效电路中含有电压降

而转子侧d轴等效电路中含有电压降

如图3(b)所示，电机定子侧q轴等效电路中含有电压降

而转子侧q轴等效电路中含有电压降

As shown in Fig. 3(a) and Fig. 3(b), the dq-axis equivalent circuit of the doubly-fed asynchronous motor includes stator resistance R _s , stator leakage inductance L _ls , mutual inductance L _m , rotor leakage inductance L _lr , and rotor resistance R _r ;

and

are the stator and rotor flux linkages respectively, p is the differential operator, ω _e is the synchronous angular velocity, and ω _r is the rotor electrical angular velocity; as shown in Figure 3(a), the d-axis equivalent circuit of the motor stator side contains a voltage drop

The d-axis equivalent circuit on the rotor side contains a voltage drop

As shown in Figure 3(b), the q-axis equivalent circuit on the stator side of the motor contains a voltage drop

The q-axis equivalent circuit on the rotor side contains a voltage drop

The operating characteristics of the DFIG motor are represented by its voltage, flux linkage, torque and motion equations; specifically, the voltage and flux linkage model of the DFIG motor in the dq synchronous reference frame is represented by the following equations:

分别为双馈异步电动机d、q轴定子磁链；v_rd、v_rq分别为双馈异步电动机d、q轴转子电压；i_rd、i_rq分别为双馈异步电动机d、q轴转子电流；

分别为双馈异步电动机d、q轴转子磁链；ω_e为双馈异步电动机同步角速度；ω_r为双馈异步电动机电角速度；R_s为双馈异步电动机定子电阻；R_r为双馈异步电动机转子电阻；L_ls为双馈异步电动机定子侧漏电感；L_m为双馈异步电动机互感；L_lr为双馈异步电动机转子侧漏电感；v _sd , v _sq are the d and q-axis stator voltages of the doubly-fed asynchronous motor, respectively; i _sd , i _sq are the d- and q-axis stator currents of the doubly-fed asynchronous motor, respectively;

are the d and q-axis stator flux linkages of the doubly-fed asynchronous motor, respectively; v _rd and v _rq are the d- and q-axis rotor voltages of the doubly-fed asynchronous motor, respectively; i _rd , i _rq are the d- and q-axis rotor currents of the doubly-fed asynchronous motor, respectively;

are the d- and q-axis rotor flux linkages of the doubly-fed asynchronous motor, respectively; ω _e is the synchronous angular velocity of the doubly-fed asynchronous motor; ω _r is the electrical angular velocity of the doubly-fed asynchronous motor; R _s is the stator resistance of the doubly-fed asynchronous motor; R _r is the doubly-fed asynchronous motor Motor rotor resistance; L _ls is the leakage inductance on the stator side of the doubly-fed asynchronous motor; _Lm is the mutual inductance of the doubly-fed asynchronous motor; L _lr is the leakage inductance on the rotor side of the doubly-fed asynchronous motor;

The torque and motion equations of the doubly-fed asynchronous motor are as follows:

T _em = 1.5n _p L _m (i _rd i _sq -i _rq i _sd )

In the above equation, T _em is the electromagnetic torque, n _p is the number of pole pairs of the motor, ω _m is the mechanical torque of the motor, ω _m0 is the initial mechanical torque of the motor, T _l is the load torque, and H is the inertia constant.

As shown in Fig. 3(c), in the detailed model of the back-to-back power electronic converter, the switching action of the power-side converter directly correlates the three-phase voltage on the power-side with the DC bus voltage; on the other hand, the switching action of the load-side converter will The three-phase voltage on the load side is directly related to the DC bus voltage.

As shown in Figure 3(c), N and N' are the neutral points of the three-phase windings of the power-side converter and the load-side converter, respectively; _essa , _essb , _essc and _era , _erb , and _rc are respectively are the three-phase electromotive force of the power-side and load-side converters; R _ssa , R _ssb , R _ssc and R _ra , R _rb , R _rc are the three-phase resistances of the power-side and load-side converters, respectively; L _ssa , L _ssb , L _ssc and L _ra , L _rb , and L _rc are the three-phase inductances of the power-side and load-side converters, respectively; v _ssa , v _ssb , v _ssc and v _ra , v _rb , and v _rc are the three-phase inductances of the power-side and load-side converters, respectively voltage; i _ss , i _r and i _C are the power-side, load-side and DC bus currents, respectively; V _dc is the DC bus voltage; C _dc is the DC bus capacitance, which is used to realize the connection between the power-side and load-side converters power decoupling.

Define S _ssa , S _ssb , S _ssc and S _lsa , S _lsb , S _lsc as the switching functions of the corresponding bridge arms of the power-side and load-side converters A, B, and C, respectively; S=0 means that the upper switch tube is disconnected, The lower switch tube is turned on, and S=1 means that the upper switch tube is turned on and the lower switch tube is turned off; then the three-phase equivalent circuit model of the back-to-back power electronic converter can be expressed by the following equations:

As shown in Figure 3(d), in the average model of back-to-back power electronic converters, the control effects of the power-side and load-side converters are represented by establishing an equivalent voltage source; specifically, the switching actions of the power-side and load-side converters is replaced by four equivalent controlled voltage sources, which represent the phase-to-phase voltage v ssab of the power-side converter AB, the phase-to-phase voltage v _ssbc of the power-side converter BC, the phase-to-phase voltage v _rab of the load-side converter AB, and the phase-to-phase voltage _of the load-side converter BC The voltages v _rbc ; u _mss and u _mls represent the modulation signals of the power-side and load-side converters, respectively.

The four phase-to-phase voltages of the power-side and load-side converters can be calculated by the following equations:

The DC bus voltage value V _dc can be obtained according to the following formula:

The control of the back-to-back power electronic converter in the AC-DC hybrid doubly-fed asynchronous all-electric marine electric propulsion system includes multiple control loops; the speed control loop is used to control the speed of the doubly-fed asynchronous motor, and the voltage control loop is used to control the DC bus voltage, the current control loop is used to control the dq-axis current value of the power-side and load-side converters; specifically, the rotor speed error signal is passed through the PI regulator to generate a reference electromagnetic torque value, so as to further calculate the reference rotor current value , its control is realized by the load-side converter; the DC bus voltage error signal passes through the PI regulator to generate the current reference value of the power-side converter, and its control is realized by the power-side converter; in the current control process, the power-side and load-side current error signals After passing through the PI regulator, the three-phase voltage control signals of the power-side and load-side converters are generated through the addition of the coupling cancellation term and the modulation algorithm.

As shown in Figure 4, when the phase-locked loop-based doubly-fed asynchronous all-electric marine electric propulsion system is used, the DC bus voltage control process determines the d-axis current reference value of the power-side converter, and the rotor speed control process determines the load-side Inverter d-axis current reference value I _rd ^* ; all superscripts * in the figure represent reference values of corresponding variables; θ _e , θ _m , θ _r and θ _slip represent synchronous electrical angle, rotor mechanical angle, rotor electrical angle and slip angle;

It can be seen that the output obtained by inputting the three-phase stator voltage V _sabc (that is, the three-phase AC voltage output by the power generation unit) into the phase-locked loop is the synchronous electrical angle θ _e and the synchronous angular velocity ω _e , and ω _e is directly used as the adjustment of the power generation unit. reference input value of the speed module;

Voltage control loop: The DC bus voltage difference is adjusted by PI to generate the reference value I _ssd ^* of the d-axis current of the power-side converter; for the purpose of realizing the complete decoupling control of the dq current of the power-side converter, the q-axis of the power-side converter is The current reference value is directly set to 0; the dq current difference of the power-side converter is adjusted by PI to obtain the dq reference voltage signal by adding compensation items 1 and 2, and obtains the three-phase reference voltage signal through Parker inverse transformation, so as to further pass The pulse width modulation strategy obtains the switching signals S _ssabc of each bridge arm of the power-side converter;

相除获得负载侧变换器d轴电流参考值I_rd ^*；以实现负载侧变换器dq电流的完全解耦控制为目的，将负载侧变换器q轴电流参考值I_rq ^*直接设置为0；负载侧变换器的dq电流差值经PI调节后通过加入补偿项3,4来获得dq参考电压信号，并通过派克反变换得到三相参考电压信号，从而进一步通过脉宽调制策略获得负载侧变换器的各桥臂开关信号S_lsabc；各个补偿项分别为：Speed control loop: The rotor angular speed difference is adjusted by PI to obtain the electromagnetic torque reference value T _em ^* , and the stator flux linkage obtained by and the estimated

The d-axis current reference value I _rd ^* of the load-side converter is obtained by dividing it; for the purpose of realizing the complete decoupling control of the dq current of the load-side converter, the q-axis current reference value I _rq ^* of the load-side converter is directly set to 0; After the dq current difference of the load-side converter is adjusted by PI, the dq reference voltage signal is obtained by adding compensation items 3 and 4, and the three-phase reference voltage signal is obtained through Parker inverse transformation, so as to further obtain the load-side transformation through the pulse width modulation strategy. The switch signal S _lsabc of each bridge arm of the device; each compensation term is:

In the formula, σ is the leakage flux coefficient, k _s is the stator coupling coefficient, and their expressions are:

As shown in Fig. 5, when the control method of the doubly-fed asynchronous all-electric marine electric propulsion system based on the stator flux linkage vector orientation based on the stator flux linkage estimation and the flux linkage angle calculation is adopted, the DC bus voltage control process determines the q-axis of the power-side converter. current reference value, and the rotor speed control process determines the load-side converter q-axis current reference value;

具体计算过程为：It can be seen that the three-phase stator voltage V _sabc and the three-phase stator current I _sabc are Clark transformed to obtain the stator voltage and current V _sαβ and I _sαβ in the two-phase stationary coordinate system, and input them into the stator flux linkage estimation and flux linkage angle. The output obtained after calculating the module is the synchronous electrical angle θ _e and the stator flux linkage

The specific calculation process is as follows:

与

来计算同步电角度θ_e的值，从而确定定子磁链的方向，即为

方向逆时针旋转θ_e的方向。According to the stator flux linkage value in the two-phase stationary coordinate system

and

to calculate the value of the synchronous electrical angle θ _e to determine the direction of the stator flux linkage, which is

The direction is the direction of the counterclockwise rotation of θ _e .

The calculation method of the synchronous electrical angle θ _e is as follows:

为0，则；if

is 0, then;

According to the stator voltage equation

与

等于0，因此dq轴定子磁链值可以通过如下表达式计算得到，At steady state, the transient value

and

is equal to 0, so the dq-axis stator flux linkage value can be calculated by the following expression,

The DC bus voltage difference is adjusted by PI to generate the reference value I _ssq ^* of the q-axis current of the power-side converter; for the purpose of realizing the complete decoupling control of the dq current of the power-side converter, the reference value I of the d-axis current of the power-side converter is _ssd ^* is directly set to 0; the dq current difference of the power-side converter is adjusted by PI to obtain the dq reference voltage signal by adding compensation items 5 and 6, and obtains the three-phase reference voltage signal through Parker inverse transformation, so as to further pass the pulse The wide modulation strategy obtains the switching signal S _ssabc of each bridge arm of the power-side converter;

相除获得负载侧变换器q轴电流参考值I_rq ^*；以实现负载侧变换器dq电流的完全解耦控制为目的，将负载侧变换器d轴电流参考值I_rd ^*直接设置为0；负载侧变换器的dq电流差值经PI调节后通过加入补偿项7,8来获得dq参考电压信号，并通过派克反变换得到三相参考电压信号，从而进一步通过脉宽调制策略获得负载侧变换器的各桥臂开关信号S_lsabc；The rotor angular velocity difference is adjusted by PI to obtain the electromagnetic torque reference value T _em ^* , and the stator flux linkage obtained by comparing with the estimated

The q-axis current reference value I _rq ^* of the load-side converter is obtained by dividing it; for the purpose of realizing the complete decoupling control of the dq current of the load-side converter, the d-axis current reference value I _rd ^* of the load-side converter is directly set to 0; After the dq current difference of the load-side converter is adjusted by PI, the dq reference voltage signal is obtained by adding compensation items 7 and 8, and the three-phase reference voltage signal is obtained through the inverse Parker transformation, so as to further obtain the load-side transformation through the pulse width modulation strategy. each bridge arm switch signal S _lsabc of the device;

The compensation terms in the control mode of the doubly-fed asynchronous all-electric marine electric propulsion system based on the vector orientation of the stator flux linkage are as follows:

Among them, ω _e represents the synchronous angular velocity, which is set to 1pu, and is used as the reference input value of the speed control module of the power generation unit.

As shown in Fig. 6, when the control mode of the doubly-fed asynchronous all-electric marine electric propulsion system based on the analog stator voltage vector orientation is adopted, the DC bus voltage control process determines the d-axis current reference value of the power-side converter, and the rotor speed control process determines Load-side converter d-axis current reference value;

和定子磁链

通常双馈异步电动机定子电阻可以忽略不计，因此同步电角度θ_e约等于磁链角

加上90°；It can be seen that the three-phase stator voltage and three-phase stator current are Clark transformed to obtain the stator voltage and current V _sαβ and _{Is αβ} in the two-phase static coordinate system, and they are input into the stator flux linkage estimation and flux linkage angle calculation module to obtain The output is the flux linkage angle

and stator flux linkage

Usually, the stator resistance of the doubly-fed asynchronous motor can be ignored, so the synchronous electrical angle θ _e is approximately equal to the flux linkage angle

plus 90°;

The synchronous angular velocity ω _e is directly set to 1pu, and it is used as the reference input value of the speed control module of the power generation unit;

The DC bus voltage difference is adjusted by PI to generate the reference value of the d-axis current of the power-side converter; for the purpose of realizing the complete decoupling control of the dq current of the power-side converter, the reference value of the q-axis current of the power-side converter is directly set to 0 ; After the dq current difference of the power-side converter is adjusted by PI, the dq reference voltage signal is obtained by adding compensation items 1 and 2, and the three-phase reference voltage signal is obtained through Parker inverse transformation, so as to further obtain the power-side voltage signal through the pulse width modulation strategy. each bridge arm switch signal S _ssabc of the converter;

The rotor angular velocity difference is adjusted by PI to obtain the electromagnetic torque reference value, and the reference value of the load-side converter d-axis current is obtained by dividing it with the estimated stator flux linkage; to achieve the complete decoupling control of the load-side converter dq current as The purpose is to directly set the q-axis current reference value of the load-side converter to 0; after the dq current difference of the load-side converter is adjusted by PI, the dq reference voltage signal is obtained by adding compensation items 3 and 4, and obtained by inverse Parker transformation three-phase reference voltage signal, thereby further obtaining the switching signal S _lsabc of each bridge arm of the load-side converter through the pulse width modulation strategy;

The compensation items in the control mode of the doubly-fed asynchronous all-electric marine electric propulsion system based on the analog stator voltage vector orientation are:

Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, etc., All should be included within the protection scope of the present invention.

Claims (2)

1. A control method of a double-fed asynchronous full-electric ship electric propulsion system based on stator flux linkage vector orientation is characterized in that the system comprises the following steps: the system comprises a power generation unit, a back-to-back power electronic converter and a double-fed asynchronous motor;

the power generation unit is used for providing electric energy for the full-electric ship; the power generation unit comprises a prime motor, a synchronous generator, an excitation control module and a speed regulation module;

the prime mover drives the synchronous generator to rotate by converting chemical energy into mechanical energy; the excitation control module is used for generating an excitation voltage signal; the synchronous generator generates three-phase alternating-current voltage on the stator side of the generator according to an excitation voltage signal generated by the excitation control module, so as to provide electric energy for the whole ship, and meanwhile, the three-phase alternating-current voltage is also used as a feedback signal to be input into the excitation control module; the speed regulating module is used for sending a power instruction to the prime motor to control the operation of the prime motor, so that the rotating speed of the synchronous generator is controlled, and the balance between the output power of the synchronous generator and the input power of a load side is ensured; the load refers to a double-fed asynchronous motor;

the power generation unit is connected with the double-fed asynchronous motor through two parallel energy paths: one of the double-fed asynchronous motor stator is directly connected with the double-fed asynchronous motor stator through an alternating current transmission line to form a main energy path; the other one is connected with a rotor of the double-fed asynchronous motor through a back-to-back power electronic converter after energy AC-DC-AC conversion to form a slip energy path;

the main energy path is used for directly inputting more than 50% of the output energy of the power generation unit into the double-fed asynchronous motor; the slip energy access is used for inputting the residual energy output by the power generation unit into the double-fed asynchronous motor, and controlling the normal operation of the double-fed asynchronous motor through the back-to-back power electronic converter;

the double-fed asynchronous motor is used for providing power for the operation of the full electric ship;

the control method comprises the following steps:

s1, calculating stator flux linkage under alpha and beta coordinate systems

According to

Calculating the synchronous electrical angle theta_e；

S2, utilizing synchronous electric angle theta_eTo stator voltage V_sabcStator current I_sabcPower supply side converter current I_ssabcCarrying out abc-dq coordinate transformation to obtain dq stator voltage V_sdqDq stator current I_sdqDq current I of power supply side converter_ssdq；

S3, synchronizing the angular velocity omega_eThe 1pu input speed regulating module is set to control the rotating speed of the synchronous generator;

s4, controlling the voltage of the direct-current bus and controlling the current of the power supply side converter:

performing PI regulation on the voltage difference value of the direct current bus to generate a q-axis current reference value I of the power side converter_ssq ^*(ii) a Reference value I of d-axis current of power supply side converter_ssd ^*Set to 0; after the dq axis current difference value of the power supply side converter is subjected to PI regulation, compensation items 5 and 6 are added respectively to obtain dq reference voltage signals, and three-phase reference voltage signals are obtained through park inverse transformation; obtaining each bridge arm switch signal S of power source side converter through pulse width modulation strategy_ssabc；

In the formula, v_sd、v_sqD, q stator voltages, i, of doubly-fed asynchronous motors, respectively_ssd、i_ssqRespectively representing d and q currents, L, of the power-side converter_ssRepresenting the line inductance of the power side converter;

s5, controlling the rotating speed of the double-fed asynchronous motor and controlling the current of a load side converter:

performing PI regulation on the rotor angular speed difference to obtain an electromagnetic torque reference value T_em ^*Is linked with the stator flux

Obtaining a q-axis current reference value I of the load side converter by phase division_rq ^*(ii) a Reference value I of d-axis current of load-side converter_rd ^*Set to 0; adjusting the dq axis current difference value of the load side converter through PI, respectively adding compensation items 7 and 8 to obtain a dq reference voltage signal, and obtaining a three-phase reference voltage signal through inverse park transformation, thereby further obtaining each bridge arm switching signal S of the load side converter through a pulse width modulation strategy_lsabc；

Wherein, ω is_slipExpressing the angular speed of slip, sigma is the magnetic leakage coefficient, L_rRepresenting rotor inductance, k_sIs the stator coupling coefficient, i_rd、i_rqThe rotor currents of the shaft d and the shaft q of the doubly-fed asynchronous motor are respectively.

2. A method for controlling a double-fed asynchronous full-electric ship electric propulsion system based on analog stator voltage vector orientation is characterized in that the system comprises the following steps: the system comprises a power generation unit, a back-to-back power electronic converter and a double-fed asynchronous motor;

the power generation unit is used for providing electric energy for the full-electric ship; the power generation unit comprises a prime motor, a synchronous generator, an excitation control module and a speed regulation module;

the prime mover drives the synchronous generator to rotate by converting chemical energy into mechanical energy; the excitation control module is used for generating an excitation voltage signal; the synchronous generator generates three-phase alternating-current voltage on the stator side of the generator according to an excitation voltage signal generated by the excitation control module, so as to provide electric energy for the whole ship, and meanwhile, the three-phase alternating-current voltage is also used as a feedback signal to be input into the excitation control module; the speed regulating module is used for sending a power instruction to the prime motor to control the operation of the prime motor, so that the rotating speed of the synchronous generator is controlled, and the balance between the output power of the synchronous generator and the input power of a load side is ensured; the load refers to a double-fed asynchronous motor;

the power generation unit is connected with the double-fed asynchronous motor through two parallel energy paths: one of the double-fed asynchronous motor stator is directly connected with the double-fed asynchronous motor stator through an alternating current transmission line to form a main energy path; the other one is connected with a rotor of the double-fed asynchronous motor through a back-to-back power electronic converter after energy AC-DC-AC conversion to form a slip energy path;

the main energy path is used for directly inputting more than 50% of the output energy of the power generation unit into the double-fed asynchronous motor; the slip energy access is used for inputting the residual energy output by the power generation unit into the double-fed asynchronous motor, and controlling the normal operation of the double-fed asynchronous motor through the back-to-back power electronic converter;

the double-fed asynchronous motor is used for providing power for the operation of the full electric ship;

the control method comprises the following steps:

s1, according to stator voltage and current V under a two-phase static coordinate system_sαβAnd I_sαβCalculating stator flux linkage

According to

Calculating magnetic linkage angle

Angle of magnetic flux linkage

Adding 90 degrees to obtain a synchronous electrical angle theta_e(ii) a Wherein theta is_eThe direction of the stator voltage vector is the same as that of the simulated stator voltage vector;

s2, utilizing synchronous electrical angle theta_eTo stator voltage V_sabcStator current I_sabcPower supply side converter current I_ssabcCarrying out abc-dq coordinate transformation to obtain dq stator voltage V_sdqDq stator current I_sdqActual value I of dq axis current of power supply side converter_ssdq；

S3, synchronizing the angular velocity omega_eThe 1pu input speed regulating module is set to control the rotating speed of the synchronous generator;

s4, controlling the voltage of the direct-current bus and controlling the current of the power supply side converter:

the voltage difference value of the direct current bus is regulated by PI to generate a d-axis current reference value I of the power side converter_ssd ^*(ii) a Reference value I of q-axis current of power supply side converter_ssq ^*Set to 0; adjusting the dq axis current difference value of the power supply side converter through PI, respectively adding compensation items 1 and 2 to obtain a dq reference voltage signal, and obtaining a three-phase reference voltage signal through inverse park transformation; obtaining each bridge arm switch signal S of power source side converter through pulse width modulation strategy_ssabc；

In the formula, v_sd、v_sqD and q stator voltages of the double-fed asynchronous motor are respectively; r_ssRepresenting line resistance, i, of the power-side converter_ssd、i_ssqRespectively representing d and q currents, L, of the power-side converter_ssRepresenting the line inductance of the power side converter;

s5, controlling the rotating speed of the double-fed asynchronous motor and controlling the current of a load side converter:

obtaining an electromagnetic torque reference value T by carrying out PI regulation on the angular speed difference value of the rotor_em ^*Is linked with the stator flux

Obtaining a d-axis current reference value I of the load-side converter by means of phase division_rd ^*(ii) a Reference value I of q-axis current of load-side converter_rq ^*Set to 0; adjusting the dq axis current difference value of a load side converter through PI, respectively adding compensation items 3 and 4 to obtain a dq reference voltage signal, and obtaining a three-phase reference voltage signal through inverse park transformation; obtaining bridge arm switches of load side converter through pulse width modulation strategySignal S_lsabc；

In the formula, R_rFor rotor resistance of doubly-fed asynchronous motors, i_rd、i_rqRotor currents of d and q axes of doubly-fed asynchronous motor, omega_slipRepresenting slip angular velocity, L_rExpressing rotor inductance, σ is the leakage coefficient, k_sIs the stator coupling coefficient.

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