CN112448652B - A two-stage staggered parallel electric drive controller and its control method - Google Patents

Abstract

The invention belongs to the technical field of drive control, and provides a two-stage staggered parallel electric drive controller which is used for connecting a motor and comprises an energy storage unit, a first-stage staggered parallel electric drive controller and a second-stage staggered parallel electric drive controller, wherein the energy storage unit is used for outputting input voltage; the direct current conversion unit is connected with the energy storage unit and used for outputting bus voltage according to the input voltage and the first pulse width modulation signal; the inversion unit is connected with the direct current conversion unit and the motor and used for outputting three-phase current according to the direct current voltage of the bus and the second pulse width modulation signal so as to drive the motor; the feedback unit is connected with the direct current conversion unit, the inversion unit and the motor, and is used for detecting the direct current voltage of the bus and outputting a voltage detection signal, detecting the phase current of the inversion unit and outputting a current detection signal, and detecting the rotating speed of the motor and outputting an angular speed signal; the control unit is connected with the direct current conversion unit, the inversion unit and the feedback unit and used for outputting a first pulse width modulation signal and a second pulse width modulation signal according to the voltage detection signal, the current detection signal and the angular speed signal.

Description

A two-stage staggered parallel electric drive controller and its control method

technical field

The invention belongs to the technical field of drive control, and in particular relates to a two-stage staggered parallel electric drive controller and a control method thereof.

Background technique

Due to the realistic pressure of transportation, energy and environment, the development of electric vehicles has become an important way for countries to improve the competitiveness of the auto industry and alleviate the energy crisis. With the development of power electronic devices and control technology, inverter-driven AC motor with variable frequency speed regulation has become the main way of traffic traction. Adding a DC/DC converter to the front stage of the traditional voltage source inverter can increase the voltage on the DC side of the inverter, avoiding the method of using batteries in series for boosting, and has better economy and safety. The DC/DC and DC/AC two-stage controller topologies are characterized by high efficiency, high power density, and bidirectional energy flow, and are being widely used.

The staggered parallel technology based on the parallel drive topology can maintain the continuous operation of the electric drive system through the corresponding fault-tolerant control strategy, and then can obtain a certain time to take measures to deal with the fault accordingly. However, in the traditional two-stage interleaved parallel electric drive controllers, most of them are implemented with independent inductors, and a large circulating current is easily generated between the parallel bridge arms, which greatly limits the high-efficiency operation of the electric drive system.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a two-stage staggered parallel electric drive controller, which aims to solve the problem of easy generation of a large circulating current between the parallel bridge arms existing in the traditional two-stage staggered parallel electric drive controller. The problem that limits the high-efficiency operation of the electric drive system.

A two-stage staggered parallel electric drive controller is used for connecting a motor, and the two-stage staggered parallel electric drive controller comprises:

Energy storage unit for outputting input voltage;

a DC conversion unit, connected to the energy storage unit, and configured to output the bus voltage according to the input voltage and the first pulse width modulation signal;

an inverter unit, connected to the DC conversion unit and the motor, and configured to output a three-phase current according to the busbar DC voltage and the second pulse width modulation signal to drive the motor;

a feedback unit, connected to the DC conversion unit, the inverter unit and the motor, for detecting the DC voltage of the bus bar and outputting a voltage detection signal, for detecting the phase current of the inverter unit and outputting the current detection a signal for detecting the rotational speed of the motor and outputting an angular velocity signal;

a control unit, connected to the DC conversion unit, the inverter unit and the feedback unit, for outputting the first pulse width modulation signal according to the voltage detection signal, the current detection signal and the angular velocity signal and the second pulse width modulated signal.

Further, the control unit includes a carrier modulation module, and the carrier modulation module is configured to adjust the carrier frequency and the magnitude of the first pulse width modulation signal according to the voltage detection signal, the current detection signal and the angular velocity signal. The magnitude of the carrier frequency of the second PWM signal.

Further, the control unit further includes a bus voltage modulation module, and the bus voltage modulation module is configured to output the bus voltage according to the angular velocity signal.

Further, the DC conversion unit includes a first coupled inductor, a first triac, a first switching device, a second switching device, a third switching device, a fourth switching device, and an output capacitor;

The first coupled inductor includes a first inductor and a second inductor, the first inductor is connected between the positive electrode of the energy storage unit and the output end of the first switching device, and the second inductor is connected between the Between the anode of the energy storage unit and the output end of the third switching device, the control end of the first switching device, the control end of the second switching device, the control end of the third switching device, and the The control terminals of the fourth switching device are all connected to the control unit, the input terminal of the first switching device and the input terminal of the third switching device are connected to the positive pole of the output capacitor, and the input terminal of the second switching device is connected to the positive pole of the output capacitor. The terminal is connected to the output terminal of the first switching device, the input terminal of the fourth switching device is connected to the input terminal of the third switching device, the output terminal of the second switching device and the output terminal of the fourth switching device The terminals are all connected to the negative pole of the output capacitor, the negative pole of the output capacitor is connected to the negative pole of the energy storage unit, and the first triac is connected to the output terminal of the first switching device and the output terminal of the third switching device. Between the output terminals, the positive pole of the output capacitor is used as the bus voltage output terminal of the DC conversion unit.

Further, the inverter unit includes a first inverter module, a second inverter module and a third inverter module;

The first inverter module, the second inverter module and the third inverter module all include a second coupled inductor, a second triac, a fifth switching device, a sixth switching device, a seventh switching device and an eighth switching device; The second coupled inductance includes a third inductance and a fourth inductance, the third inductance is connected between the output end of the fifth switching device and the motor, and the fourth inductance is connected to the output of the seventh switching device Between the terminal and the motor, the control terminal of the fifth switching device, the control terminal of the sixth switching device, the control terminal of the seventh switching device and the control terminal of the eighth switching device are all connected to the control terminal. unit, the input terminal of the fifth switching device and the input terminal of the seventh switching device are connected to the positive pole of the output capacitor, the input terminal of the sixth switching device is connected to the output terminal of the fifth switching device, so The input end of the eighth switching device is connected to the input end of the seventh switching device, the output end of the sixth switching device and the output end of the eighth switching device are both connected to the negative electrode of the output capacitor, and the Two triacs are connected between the output terminal of the fifth switching device and the output terminal of the seventh switching device, and the common terminal of the third inductance and the fourth inductance serves as the third terminal of the inverter unit. Phase current output.

Further, it also includes a discharge circuit, the discharge circuit includes a discharge switch and a first resistor, the first end of the discharge switch is connected to the positive pole of the output capacitor, and the second end of the discharge switch is connected through the first resistor The negative pole of the output capacitor.

In another aspect, a control method of the above-mentioned two-stage staggered parallel electric drive controller is also provided, and the control method includes:

Obtain the DC voltage of the busbar and generate the voltage detection signal, the phase current of the inverter unit and generate the current detection signal and the rotational speed of the motor and generate the angular velocity signal;

generating a bus reference voltage according to the angular velocity signal, and generating a carrier frequency signal according to the voltage detection signal, the current detection signal and the angular velocity signal;

A first pulse width modulation signal is generated according to the bus reference voltage and the carrier frequency signal, and a second pulse width modulation signal is generated according to the carrier frequency signal, the current detection signal and the angular velocity signal.

Further, the step of generating the bus reference voltage according to the angular velocity signal includes:

comparing the angular velocity signal with a first preset angular velocity, and comparing the angular velocity signal with a second preset angular velocity; wherein the second preset angular velocity is greater than the first preset angular velocity;

If the angular velocity signal is less than the first preset angular velocity, set the bus reference voltage as the input voltage;

If the angular velocity signal is in a size range between the first preset angular velocity and the second preset angular velocity, generating the bus reference voltage according to the angular velocity signal;

If the angular velocity signal is greater than the second preset angular velocity, the bus reference voltage is set as a preset bus reference voltage.

Further, the step of generating a carrier frequency signal according to the voltage detection signal, the current detection signal and the angular velocity signal includes:

Calculate the switching loss variation and the coupling inductance loss variation according to the voltage detection signal, the current detection signal and the angular velocity signal;

If the sum of the variation of the switching loss and the variation of the coupling inductor loss is less than 0, generating the carrier frequency signal according to the angular velocity signal;

If the sum of the variation of the switching loss and the variation of the coupling inductor loss is greater than or equal to 0, the carrier frequency signal is set to a preset carrier frequency.

Further, the DC conversion unit and the inverter unit include at least one inverter module, and the inverter module includes a first bridge arm and a second bridge arm connected in parallel and connected to the first bridge arm and the second bridge arm. A bidirectional thyristor between bridge arms; the control method further includes:

When the first bridge arm or the second bridge arm in parallel has a short circuit or a short circuit fault, the fault bridge arm can be removed: the fast fuse is blown when a short circuit fault occurs, and the thyristor is triggered and turned on when a short circuit or open circuit fault occurs.

The above-mentioned two-stage interleaved parallel electric drive controller adjusts and controls the first pulse width modulation signal output by the DC conversion unit and the second pulse width modulation signal output by the control inverter unit in real time according to the feedback bus voltage, motor speed and phase current. , so as to improve the operating efficiency of the system and improve the electromagnetic noise and vibration noise of the electric drive system.

Description of drawings

1 is a schematic diagram of a circuit structure of a two-stage interleaved parallel electric drive controller provided by an embodiment of the present invention;

2 is a schematic circuit diagram of a two-stage interleaved parallel electric drive controller provided by an embodiment of the present invention;

FIG. 3 is a flowchart of a control method of a two-stage interleaved parallel electric drive controller provided by an embodiment of the present invention.

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.

FIG. 1 shows a schematic diagram of a circuit structure of a two-stage staggered parallel electric drive controller provided by an embodiment of the present invention. As shown in FIG. 1 , the two-stage interleaved parallel electric drive controller includes an energy storage unit 10 , a DC conversion unit 20 , an inverter unit 30 , a feedback unit 40 and a control unit 50 .

The energy storage unit 10 is used for outputting the input voltage; the DC conversion unit 20 is connected to the energy storage unit 10 for outputting the bus voltage according to the input voltage and the first pulse width modulation signal; the inverter unit 30 is connected with the DC conversion unit 20 is connected to the motor 60 for outputting three-phase current according to the DC voltage of the bus and the second pulse width modulation signal to drive the motor 60; the feedback unit 40 is connected to the DC conversion unit 20 and the inverter unit 30 and the motor 60 are connected for detecting the DC voltage of the bus bar and outputting a voltage detection signal, for detecting the phase current of the inverter unit 30 and outputting a current detection signal, for detecting the rotational speed of the motor 60 and outputting a current detection signal. Output angular velocity signal; the control unit 50 is connected to the DC conversion unit 20, the inverter unit 30 and the feedback unit 40, and is used for outputting the angular velocity signal according to the voltage detection signal, the current detection signal and the angular velocity signal. the first pulse width modulation signal and the second pulse width modulation signal.

The above-mentioned two-stage interleaved parallel electric drive controller adjusts and controls the first pulse width modulation signal output by the DC conversion unit 20 and the second pulse output by the control inverter unit 30 in real time according to the feedback bus voltage, motor 60 speed and phase current. Width modulate the signal, thereby improving the operating efficiency of the system and improving the electromagnetic noise and vibration noise of the electric drive system.

In one embodiment, the control unit 50 further includes a busbar voltage modulation module, the busbar voltage modulation module is configured to output a busbar reference voltage according to the angular velocity signal, and the control unit 50 according to the busbar reference voltage, voltage The detection signal, the current detection signal, and the angular velocity signal output the first pulse width modulation signal. Specifically, as shown in equation (1), when the angular velocity signal is less than the first preset angular velocity ω _s1 , the bus reference voltage is set to the input voltage Vin output by the energy storage unit 10; When setting the size range between the angular velocity ω _s1 and the second preset angular velocity ω _s2 , the bus reference voltage is adjusted according to the actual angular velocity of the motor 60, that is, the real-time adjustment is carried out according to the angular velocity signal obtained by the feedback unit 40. The specific adjustment formula is detailed in In formula (1), when the angular velocity signal is greater than the second preset angular velocity ω _s2 , the bus reference voltage is set to the maximum value V _{dc_max} , and the motor 60 enters the field weakening control. The bus reference voltage is adjusted according to the actual angular velocity of the motor 60, and the control unit 50 adjusts the DC bus voltage according to the bus reference voltage, which can reduce the voltage stress of the switching tube, thereby reducing the switching loss. In addition, the real-time adjustment of the DC bus voltage can improve the circuit loss in the coupled inductor.

In one embodiment, the control unit 50 includes a carrier modulation module, and the carrier modulation module is configured to adjust the first pulse width modulation signal according to the voltage detection signal, the current detection signal and the angular velocity signal the size of the carrier frequency and the size of the carrier frequency of the second pulse width modulated signal. Specifically, the carrier modulation module calculates the switching loss variation ΔPsw and the coupling inductor loss variation ΔPc after the carrier frequency is adjusted according to the voltage detection signal, the current detection signal and the angular velocity signal. When the switching loss variation ΔPsw and When the sum of the coupling inductor loss variation ΔPc is less than 0, the carrier frequency angular velocity signal is adjusted, as shown in equation (2); when the sum of the switching loss variation ΔPsw and the coupling inductor loss variation ΔPc is greater than or equal to 0, the carrier frequency maintained at the set preset frequency. The carrier frequency control scheme can further optimize the overall loss of the system without affecting the designed saturation flux density of the coupled inductor.

Wherein, f _{s_min} is the preset minimum carrier frequency, f _{s_max} is the preset maximum carrier frequency, and ω _s1 and ω _s2 are the first preset angular velocity and the second preset angular velocity. When the angular velocity signal ω _s is less than or equal to the first preset angular velocity ω _s1 , that is, ω _s ≤ω _s1 , the carrier frequency is equal to the set minimum switching frequency, that is, f _s =f _{s_min} ; when the actual motor 60 angular velocity satisfies ω _s1 <ω When _s <ω _s2 , the carrier frequency is adjusted proportionally according to the angular velocity of the motor 60, and the specific adjustment formula is shown in the above formula (2); when the actual angular velocity of the motor 60 satisfies ω _s ≥ ω _s2 , the carrier frequency is equal to the set The maximum switching frequency is f _s =f _{s_max} .

The DC conversion unit 20 includes a first coupled inductor L1, a first triac TR1, a first switching device S1, a second switching device S2, a third switching device S3, a fourth switching device S4, and an output capacitor C; A coupled inductor L1 includes a first inductor and a second inductor, the first inductor is connected between the positive electrode of the energy storage unit 10 and the output end of the first switching device S1, and the second inductor is connected between the Between the positive electrode of the energy storage unit 10 and the output end of the third switching device S3, the control end of the first switching device S1, the control end of the second switching device S2, the third switching device S3 The control terminal of the first switching device S1 and the control terminal of the fourth switching device S4 are connected to the control unit 50, and the input terminal of the first switching device S1 and the input terminal of the third switching device S3 are connected to the output capacitor C. Positive pole, the input end of the second switching device S2 is connected to the output end of the first switching device S1, the input end of the fourth switching device S4 is connected to the output end of the third switching device S3, and the second switching device S4 is connected to the output end of the third switching device S3. The output end of the switching device S2 and the output end of the fourth switching device S4 are both connected to the negative electrode of the output capacitor C, the negative electrode of the output capacitor C is connected to the negative electrode of the energy storage unit 10, and the first triac TR1 is connected between the output terminal of the first switching device S1 and the output terminal of the third switching device S3 , and the positive pole of the output capacitor C serves as the bus voltage output terminal of the DC conversion unit 20 .

Further, the first switching device S1, the second switching device S2, the third switching device S3 and the fourth switching device S4 are all connected in series with a fuse, and the first switching device S1 and the second switching device S2 are connected to form a first bridge arm, The third switching device S3 and the fourth switching device S4 are connected to form a second bridge arm, and the first bridge arm and the second bridge arm form a parallel structure. When a short-circuit fault occurs in the bridge arm, the fuse connected to the faulty bridge arm corresponds to It will be quickly blown, thereby isolating the faulty bridge arm, and at the same time, the control unit 50 triggers the corresponding first triac TR1 to be turned on to realize the switching of the coupled inductor winding, thereby realizing the fault-tolerant operation of the system.

The inverter unit 30 includes a first inverter module, a second inverter module, and a third inverter module, and the first inverter module, the second inverter module, and the third inverter module are all connected to the DC conversion unit 20 . , receives the bus voltage output by the DC conversion unit 20 , inverts the DC voltage and outputs three-phase current to the motor 60 . The first inverter module, the second inverter module, and the third inverter module have the same rectifier circuit structure, and the inverter circuit includes a second coupled inductor L2, a second triac TR2, a fifth switching device S5, and a sixth switch device S6, seventh switching device S7 and eighth switching device S8; the second coupled inductor L2 includes a third inductor and a fourth inductor, the third inductor is connected to the output end of the fifth switching device S5 and the motor 60, the fourth inductor is connected between the output end of the seventh switching device S7 and the motor 60, the control end of the fifth switching device S5, the control end of the sixth switching device S6, the The control terminal of the seventh switching device S7 and the control terminal of the eighth switching device S8 are both connected to the control unit 50, and the input terminal of the fifth switching device S5 is connected to the input terminal of the seventh switching device S7. The positive pole of the output capacitor C, the input end of the sixth switching device S6 is connected to the output end of the fifth switching device S5, and the input end of the eighth switching device S8 is connected to the output of the seventh switching device S7 terminal, the output terminal of the sixth switching device S6 and the output terminal of the eighth switching device S8 are both connected to the negative pole of the output capacitor C, and the second triac TR2 is connected to the fifth switching device S5 Between the output terminal and the output terminal of the seventh switching device S7 , the common terminal of the third inductor and the fourth inductor is used as the three-phase current output terminal of the inverter unit 30 .

Similarly, the fifth switching device S5, the sixth switching device S6, the seventh switching device S7 and the eighth switching device S8 are all connected in series with a fuse, and the fifth switching device S5 and the sixth switching device S6 are connected to form a third bridge arm, The seventh switching device S7 and the eighth switching device S8 are connected to form a fourth bridge arm, and the third bridge arm and the fourth bridge arm are formed in a parallel structure. Taking the first rectifier module of the inverter unit 30 as an example: when the fifth switching device S5 or the sixth switching device S6 has a short-circuit fault, the fuses F5 and F6 are quickly blown, the third bridge arm is cut off, and the second The triac TR2 is triggered by the control unit 50, the winding of the second coupled inductance L2 is switched to the fourth bridge arm, the circulating current of the second coupled inductance L2 will disappear, the leakage inductance acts as a line inductance, and remains with the remaining second rectifier module and the first bridge. The two phases of the three rectifier modules are kept symmetrical; when the fifth switching device S5 or the sixth switching device S6 has an open circuit fault, the second triac TR2 is triggered by the control unit 50, and the winding of the second coupling inductor L2 is switched to the fourth bridge arm, It still maintains two-phase symmetry with the remaining second rectifier module and third rectifier module. The fault-tolerant operation can ensure that the load motor 60 can have a power output of 50%, and can maintain the normal operation of the circuit system.

The two-stage interleaved parallel electric drive controller also includes a discharge circuit, the discharge circuit includes a discharge switch and a first resistor R, the first end of the discharge switch S0 is connected to the positive pole of the output capacitor C, and the discharge switch S0 is connected to the positive pole of the output capacitor C. The second terminal is connected to the negative electrode of the output capacitor C through the first resistor R. The discharge switch S0 is an active switch. When the circuit is running normally, the discharge switch S0 is in an open state. When the discharge switch S0 is closed, the output capacitor C, the discharge switch S0 and the first resistor R form a discharge loop to realize the active discharge of the output capacitor C. Discharge to ensure the stable operation of the circuit system.

Further, the control unit 50 further includes a carrier phase shifting module, and the phase shifting module is configured to adjust the phase of the first PWM signal and the phase of the second PWM signal. Specifically, in order to obtain the smallest boost inductor current ripple, the carrier phase shift angle between the first bridge arm and the second bridge arm in the DC conversion unit 20 is set to 180°; in order to suppress the high frequency vibration of the motor 60 , the carrier phase shift angle between the third bridge arm and the fourth bridge arm in the inverter unit is set to 90°, which can suppress the electromagnetic interference of the electric drive system and the common mode current of the motor 60, and further improve the electric drive system. comprehensive performance.

Compared with the traditional three-phase inverter direct drive motor form, a two-stage interleaved parallel electric drive controller suitable for electric vehicles proposed by the present invention has the ability of real-time adjustment of the DC bus voltage and bidirectional flow of energy, Power density can be significantly improved, fault-tolerant operation can be achieved, and the reliability of the electric drive system can be enhanced. In addition, through the real-time regulation of bus voltage, carrier phase and carrier frequency, the operating efficiency of the system can be further improved, and the electromagnetic noise and vibration noise of the electric drive system can be improved.

As shown in FIG. 3 , on the basis of the above-mentioned two-stage staggered parallel electric drive controller, this embodiment also proposes a control method of a two-stage staggered parallel electric drive controller, which includes:

In step S100, obtain the DC voltage of the bus and generate the voltage detection signal, the phase current of the inverter unit and generate the current detection signal and the rotational speed of the motor and generate the angular velocity signal;

In step S200, a bus reference voltage is generated according to the angular velocity signal, and a carrier frequency signal is generated according to the voltage detection signal, the current detection signal and the angular velocity signal;

In step S300, a first pulse width modulation signal is generated according to the bus reference voltage and the carrier frequency signal, and a second pulse width modulation signal is generated according to the carrier frequency signal, the current detection signal and the angular velocity signal.

Wherein, step S200 includes:

comparing the angular velocity signal with a first preset angular velocity, and comparing the angular velocity signal with a second preset angular velocity; wherein the second preset angular velocity is greater than the first preset angular velocity;

If the angular velocity signal is less than the first preset angular velocity, set the bus reference voltage as the input voltage;

If the angular velocity signal is in a size range between the first preset angular velocity and the second preset angular velocity, generating the bus reference voltage according to the angular velocity signal;

If the angular velocity signal is greater than the second preset angular velocity, the bus reference voltage is set as a preset bus reference voltage.

Wherein, step S200 further includes:

Calculate the switching loss variation and the coupling inductance loss variation according to the voltage detection signal, the current detection signal and the angular velocity signal;

If the sum of the variation of the switching loss and the variation of the coupling inductor loss is less than 0, generating the carrier frequency signal according to the angular velocity signal;

If the sum of the variation of the switching loss and the variation of the coupling inductor loss is greater than or equal to 0, the carrier frequency signal is set to a preset carrier frequency.

The DC conversion unit and the inverter unit in the above-mentioned two-stage interleaved parallel electric drive controller include at least one inverter module, and the inverter module includes a first bridge arm and a second bridge arm connected in parallel and connected to the A triac between the first bridge arm and the second bridge arm; the control method further includes:

When the first bridge arm or the second bridge arm in parallel has a short circuit or a short circuit fault, the fault bridge arm can be removed: the fast fuse is blown when a short circuit fault occurs, and the thyristor is triggered and turned on when a short circuit or open circuit fault occurs.

The above descriptions 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 shall be included in the protection of the present invention. within the range.

Claims (8)

1. A two-stage staggered parallel electric drive controller for connecting an electric motor, the two-stage staggered parallel electric drive controller comprising:

the energy storage unit is used for outputting input voltage;

the direct current conversion unit comprises a first coupling inductor, a first bidirectional thyristor, a first switch device, a second switch device, a third switch device, a fourth switch device and an output capacitor, wherein the first coupling inductor comprises a first inductor and a second inductor, the first inductor is connected between the anode of the energy storage unit and the output end of the first switch device, the second inductor is connected between the anode of the energy storage unit and the output end of the third switch device, the control end of the first switch device, the control end of the second switch device, the control end of the third switch device and the control end of the fourth switch device are all connected with the control unit, the input end of the first switch device and the input end of the third switch device are connected with the anode of the output capacitor, and the input end of the second switch device is connected with the output end of the first switch device, the input end of the fourth switching device is connected with the input end of the third switching device, the output ends of the second and fourth switching devices are both connected with the cathode of the output capacitor, the cathode of the output capacitor is connected with the cathode of the energy storage unit, the first bidirectional thyristor is connected between the output end of the first switching device and the output end of the third switching device, and the anode of the output capacitor is used as the bus voltage output end of the direct current conversion unit;

the first inverter module, the second inverter module and the third inverter module respectively comprise a second coupling inductor, a second bidirectional thyristor, a fifth switching device, a sixth switching device, a seventh switching device and an eighth switching device; the second coupling inductor comprises a third inductor and a fourth inductor, the third inductor is connected between the output end of the fifth switching device and the motor, the fourth inductor is connected between the output end of the seventh switching device and the motor, the control end of the fifth switching device, the control end of the sixth switching device, the control end of the seventh switching device and the control end of the eighth switching device are all connected with the control unit, the input end of the fifth switching device and the input end of the seventh switching device are connected with the anode of the output capacitor, the input end of the sixth switching device is connected with the output end of the fifth switching device, the input end of the eighth switching device is connected with the input end of the seventh switching device, and the output end of the sixth switching device and the output end of the eighth switching device are both connected with the cathode of the output capacitor, the second bidirectional thyristor is connected between the output end of the fifth switching device and the output end of the seventh switching device, and the common connection end of the third inductor and the fourth inductor is used as a three-phase current output end of the inverter unit;

the feedback unit is connected with the direct current conversion unit, the inversion unit and the motor, and is used for detecting the direct current voltage of the bus and outputting a voltage detection signal, detecting the phase current of the inversion unit and outputting a current detection signal, and detecting the rotating speed of the motor and outputting an angular speed signal;

and the control unit is connected with the direct current conversion unit, the inversion unit and the feedback unit and used for outputting the first pulse width modulation signal and the second pulse width modulation signal according to the voltage detection signal, the current detection signal and the angular speed signal.

2. The two-stage interleaved parallel electrical drive controller as claimed in claim 1 wherein said control unit comprises a carrier modulation module for adjusting a carrier frequency magnitude of said first pulse width modulated signal and a carrier frequency magnitude of said second pulse width modulated signal based on said voltage detection signal, said current detection signal and said angular velocity signal.

3. The two-stage interleaved parallel electrical drive controller of claim 1 wherein said control unit further comprises a bus voltage modulation module for outputting said bus voltage in accordance with said angular velocity signal.

4. The two-stage interleaved parallel electric drive controller as claimed in claim 1 further comprising a discharge circuit, said discharge circuit comprising a discharge switch and a first resistor, wherein a first terminal of said discharge switch is connected to a positive terminal of said output capacitor, and a second terminal of said discharge switch is connected to a negative terminal of said output capacitor through said first resistor.

5. A control method for a two-stage interleaved parallel electric drive controller as claimed in any one of claims 1 to 4, the control method comprising:

acquiring direct-current voltage of a bus and generating a voltage detection signal, phase current of an inverter unit and a current detection signal and the rotating speed of a motor and generating an angular speed signal;

generating a bus reference voltage according to the angular velocity signal, and generating a carrier frequency signal according to the voltage detection signal, the current detection signal and the angular velocity signal;

and generating a first pulse width modulation signal according to the bus reference voltage and the carrier frequency signal, and generating a second pulse width modulation signal according to the carrier frequency signal, the current detection signal and the angular speed signal.

6. The control method of claim 5, wherein the step of generating a bus reference voltage from the angular velocity signal comprises:

comparing the angular velocity signal with a first preset angular velocity, and comparing the angular velocity signal with a second preset angular velocity; wherein the second preset angular velocity is greater than the first preset angular velocity;

if the angular velocity signal is smaller than the first preset angular velocity, setting the bus reference voltage as the input voltage;

if the angular velocity signal is in the range between the first preset angular velocity and the second preset angular velocity, generating the bus reference voltage according to the angular velocity signal;

and if the angular velocity signal is greater than the second preset angular velocity, setting the bus reference voltage as a preset bus reference voltage.

7. The control method according to claim 5, wherein the step of generating a carrier frequency signal from the voltage detection signal, the current detection signal, and the angular velocity signal includes:

calculating a switching loss variation and a coupling inductance loss variation according to the voltage detection signal, the current detection signal and the angular velocity signal;

if the sum of the switching loss variation and the coupling inductance loss variation is less than 0, generating the carrier frequency signal according to the angular velocity signal;

and if the sum of the switching loss variation and the coupling inductance loss variation is greater than or equal to 0, setting the carrier frequency signal as a preset carrier frequency.

8. The control method according to claim 5, wherein the DC conversion unit and the inversion unit at least comprise one inversion module, and the inversion module comprises a first bridge arm, a second bridge arm and a bidirectional thyristor connected between the first bridge arm and the second bridge arm in parallel; the control method further comprises the following steps:

when the first bridge arm or the second bridge arm connected in parallel is in short circuit or short circuit fault, the fault bridge arm can be cut off: the fast fuse is fused when short circuit fault occurs, and the thyristor is triggered to be conducted when short circuit fault or open circuit fault occurs.

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