Disclosure of Invention
The embodiment of the invention aims to provide a method and a device for controlling the field weakening of a double three-phase permanent magnet synchronous motor. In order to achieve the above object, a first aspect of the present invention provides a method for flux weakening control of a dual three-phase permanent magnet synchronous motor, including:
collecting six-phase stator current of a double three-phase permanent magnet synchronous motor;
transforming the six-phase stator current into three sub-planes through spatial decoupling to transform into sub-plane currents;
performing rotation transformation on the sub-plane current to obtain a first coordinate system feedback current and a second coordinate system feedback current;
inputting the difference value of the given current of the first coordinate system and the feedback current of the first coordinate system into a first regulator to calculate a first given voltage and a second given voltage, and inputting the difference value of the given current of the second coordinate system and the feedback current of the second coordinate system into a second regulator to calculate a third given voltage and a fourth given voltage;
the first coordinate system given current comprises a first coordinate system d-axis given current id *And a first coordinate system q-axis given current iq *Wherein the first coordinate system d-axis gives the current id *Given by a flux weakening controller, the feedback voltage v of the flux weakening controllermThe voltage is obtained through a first given voltage and a second given voltage;
subjecting the first given voltage and the second given voltage to vector control TparkInversely transforming to obtain fifth given voltage, sixth given voltage, third given voltage and fourth given voltage through vector control TdqzPerforming inverse transformation to obtain a seventh given voltage and an eighth given voltage;
carrying out spatial decoupling inverse transformation on the fifth given voltage, the sixth given voltage, the seventh given voltage and the eighth given voltage to obtain given value parameters of each phase voltage of the double three-phase permanent magnet synchronous motor;
and driving a switching device of the inverter by using PWM (pulse-width modulation) according to the given value parameter of each phase voltage of the double three-phase permanent magnet synchronous motor.
Optionally, the six-phase stator currents are transformed to the three sub-planes by spatial decoupling, including: the spatial decoupling transformation matrix is formula (1);
wherein [ T6]Is a spatial decoupling transformation matrix.
Optionally, the three sub-planes are a fundamental sub-plane, a harmonic sub-plane and a second harmonic sub-plane, respectively; the sub-plane current comprises a fundamental sub-plane current iα、iβHarmonic sub-plane current iz1、iz2And a second harmonic sub-plane current io1、io2。
Optionally, the q axis of the first coordinate system gives the current iq *From torque current command iqcmd *Obtained by means of a current limiter.
Optionally, the feedback voltage v of the field weakening controllermObtained according to the following equation (2):
wherein v ismIs the feedback voltage of the field weakening controller, vd *Is a first given voltage, vq *Is a second given voltage.
Optionally, the second coordinate system gives a given current value idz *And iqz *Are all 0.
Optionally, a fundamental sub-plane current iα、iβAnd harmonic sub-plane current iz1、iz2And performing rotation transformation to obtain a coordinate system feedback current, wherein: fundamental wave sub-plane current iα、iβT defined by formula (3)parkConverted into a first coordinate system feedback current id、iq(ii) a Harmonic sub-plane current iz1、iz2T defined by equation (4)dqzConverted into a second coordinate system feedback current idz、iqz;
Wherein, thetaeIs the rotor electrical angle, Fd、FqIs a component in a fundamental sub-plane in a first coordinate system of the double three-phase permanent magnet synchronous motor, Fdz、FqzIs a component in a harmonic sub-plane under a second coordinate system of the double three-phase permanent magnet synchronous motor, Fα、FβIs a component in the fundamental sub-plane of the double three-phase permanent magnet synchronous motor, Fz1And Fz2Are components in the harmonic sub-plane.
Optionally, calculating, by the first regulator, a given first voltage and a given second voltage by subtracting the given current of the first coordinate system from the feedback current of the first coordinate system, and calculating, by the second regulator, a third given voltage and a fourth given voltage by subtracting the given current of the second coordinate system from the feedback current of the second coordinate system includes:
adjusting the difference between the given current of the second coordinate system and the feedback current of the second coordinate system through a second regulator defined by formula (5) to obtain a third given voltage and a fourth given voltage;
wherein G isPR6(s) is a second regulator, KpAnd KIProportional and harmonic coefficients, ω, of the second regulator, respectivelycTo cut-off frequency, ω6Is the resonance frequency, which is six times the electrical frequency of the fundamental wave of the motor.
Optionally, the performing spatial decoupling inverse transformation on a fifth given voltage, a sixth given voltage, a seventh given voltage, and an eighth given voltage to obtain given value parameters of voltages of each phase of the dual three-phase permanent magnet synchronous motor, further includes:
the given voltage provided by the second harmonic sub-plane is a zero-sequence voltage with a reference value of 0.
The invention provides a device for controlling the field weakening of a double three-phase permanent magnet synchronous motor, which comprises:
configured to perform any of the above-described methods for flux weakening control of a dual three-phase permanent magnet synchronous motor.
The invention can eliminate the sixth harmonic voltage in the feedback voltage of the double three-phase permanent magnet synchronous motor during the flux weakening control, thereby eliminating the flux weakening current sixth harmonic. Compared with the traditional double three-phase weak magnetic control, the double three-phase permanent magnet synchronous motor control method is superior to the traditional weak magnetic control in the aspects of current balance and harmonic current of the double three-phase permanent magnet synchronous motor.
With the above technical solutions, other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description.
Detailed Description
The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating embodiments of the invention, are given by way of illustration and explanation only, not limitation.
Fig. 1 schematically shows a schematic diagram of a method for flux weakening control of a dual three-phase permanent magnet synchronous motor according to an embodiment of the invention. As shown in fig. 1, in an embodiment of the present invention, a method for flux weakening control of a dual three-phase permanent magnet synchronous motor is provided, including the following steps:
step 101, collecting six-phase stator current of a double three-phase permanent magnet synchronous motor;
102, transforming the six-phase stator current into three sub-planes through spatial decoupling so as to transform the six-phase stator current into a sub-plane current;
six-phase stator currents of the double three-phase permanent magnet synchronous motor are collected, and the six-phase stator currents of the double three-phase permanent magnet synchronous motor are converted into three sub-planes through a space decoupling transformation matrix and converted into sub-plane currents.
In one embodiment, the six-phase stator currents are transformed to three sub-planes by spatial decoupling, including: the spatial decoupling transformation matrix is formula (1);
wherein [ T6]Is a spatial decoupling transformation matrix.
The six-phase stator current of the double three-phase permanent magnet synchronous motor is converted into three sub-planes through the formula (1) so as to be converted into sub-plane current.
In one embodiment, the three sub-planes are a fundamental sub-plane, a harmonic sub-plane, and a second harmonic sub-plane, respectively; the sub-plane current comprises a fundamental sub-plane current iα、iβHarmonic sub-plane current iz1、iz2And a second harmonic sub-plane current io1、io2。
The fundamental sub-plane is alpha-beta sub-plane, and the harmonic sub-plane is z1-z2Sub-plane, the second harmonic sub-plane being o1-o2A sub-plane. Six-phase stator current of the double three-phase permanent magnet synchronous motor is collected, and the six-phase stator current of the double three-phase permanent magnet synchronous motor is converted to an alpha-beta sub-plane and z through a space decoupling transformation matrix formula (1)1-z2Sub-planes and o1-o2Three sub-planes to form a sub-plane current, wherein the alpha-beta sub-plane current is iα、iβ,z1-z2A sub-plane current of iz1、iz2,o1-o2A sub-plane current of io1、io2。
Six-phase stator current of the double three-phase permanent magnet synchronous motor is transformed to three planes through a space decoupling transformation matrix formula (1), and the six-phase stator current is respectively alpha-beta sub-plane current: i.e. iα、iβ;z1-z2Sub-plane current: i.e. iz1、iz2(ii) a Because two sets of windings of the double three-phase permanent magnet synchronous motor are isolated from neutral points, the motor has a structure of1-o2The sub-planes have no current.
103, carrying out rotation conversion on the sub-plane current to obtain a first coordinate system feedback current and a second coordinate system feedback current;
six-phase stator current of double three-phase permanent magnet synchronous motor is transformed through spatial decouplingMatrix equation (1), transformed to three planes, is the α - β sub-plane current: i.e. iα、iβ;z1-z2Sub-plane current: i.e. iz1、iz2Converting the sub-plane current iα、iβRotating and transforming to obtain feedback current of the first coordinate system and converting the current of the sub-plane iz1、iz2The rotation transformation obtains a second coordinate system feedback current, the first coordinate system is a dq coordinate system, and the second coordinate system is dqz coordinate system. And performing rotation transformation on the sub-plane current to obtain dq coordinate system feedback current and dqz coordinate system feedback current.
In one embodiment, the fundamental sub-plane current iα、iβAnd harmonic sub-plane current iz1、iz2And performing rotation transformation to obtain a coordinate system feedback current, wherein: fundamental wave sub-plane current iα、iβT defined by formula (3)parkConverted into a first coordinate system feedback current id、iq(ii) a Harmonic sub-plane current iz1、iz2T defined by equation (4)dqzConverted into a second coordinate system feedback current idz、iqz;
Wherein theta iseIs the rotor electrical angle, Fd、FqIs a component in a fundamental sub-plane in a first coordinate system of the double three-phase permanent magnet synchronous motor, Fdz、FqzIs a component in a harmonic sub-plane under a second coordinate system of the double three-phase permanent magnet synchronous motor, Fα、FβIs a component in the fundamental sub-plane of the double three-phase permanent magnet synchronous motor, Fz1And Fz2Are components in the harmonic sub-plane.
Alpha-beta sub-plane current iα、iβThrough the formula (3) TparkConversion to dq coordinate system feedback current id、iq,z1-z2Sub-plane current iz1、iz2Through the formula (4) TdqzTransformed into dqz coordinate system feedback current idz、iqz. Theta in the formula (3)eIs the rotor electrical angle, Fd、FqIs a component in an alpha-beta sub-plane under a dq coordinate system of the double three-phase permanent magnet synchronous motor, Fα、FβIs a component in an alpha-beta sub-plane of the double three-phase permanent magnet synchronous motor, theta in formula (4)eIs the rotor electrical angle, Fdz、FqzIs z under a double three-phase permanent magnet synchronous motor dqz coordinate system1-z2Component of the sub-plane, Fz1And Fz2Is z1-z2Component in the sub-plane.
And 104, inputting the difference value of the given current of the first coordinate system and the feedback current of the first coordinate system into a first regulator to calculate a first given voltage and a second given voltage, and inputting the difference value of the given current of the second coordinate system and the feedback current of the second coordinate system into a second regulator to calculate a third given voltage and a fourth given voltage.
The first regulator may be a proportional integral regulator and the second regulator may be a proportional resonant regulator. And calculating the difference between the dq coordinate system given current and the dq coordinate system feedback current through a proportional integral regulator to obtain a first given voltage and a second given voltage. Wherein the first given voltage is
The second given voltage is
dqz the difference between the given current of the coordinate system and the feedback current of the dqz coordinate system is calculated by a proportional resonant regulator to obtain a third given voltage and a fourth given voltage, wherein the third given voltage is
A fourth given voltage of
In one embodiment, calculating the difference between the first coordinate system set current and the first coordinate system feedback current by the first regulator to obtain the given first voltage and the given second voltage, and calculating the difference between the second coordinate system set current and the second coordinate system feedback current by the second regulator to obtain the third set voltage and the fourth set voltage comprises: regulating the given current of the second coordinate system and the feedback current of the second coordinate system through a second regulator defined by a formula (5) to obtain a third given voltage and a fourth given voltage;
wherein G isPR6(s) is a second regulator, KpAnd KIProportional and harmonic coefficients, ω, of the second regulator, respectivelycTo cut-off frequency, ω6Is the resonance frequency, which is six times the electrical frequency of the fundamental wave of the motor.
The difference between the given current of the dq coordinate system and the feedback current of the dq coordinate system is calculated by a proportional-integral regulator to obtain a first given voltage
And a second given voltage
dqz coordinate system given current and dqz coordinate system feedback current are differed to obtain third given voltage through calculation of a proportional resonant regulator
And a fourth given voltage
Wherein the proportional resonant controller is G
PR6(s), the expression is:
wherein KpAnd KIProportional coefficient and resonance coefficient, omega, of the proportional resonance controller, respectivelycTo cut-off frequency, ω6The proportional resonant controller has maximum gain at the resonant point and no phase lag at the resonant frequency which is equal to the six-time multiplication of the fundamental wave electric frequency of the motor, and the resonant point can be adjusted in real time according to the motor frequency.
105, the first coordinate system given current comprises a first coordinate system d-axis given current id *And a first coordinate system q-axis given current iq *Wherein the first coordinate system d-axis gives the current id *Given by a flux weakening controller, the feedback voltage v of the flux weakening controllermObtained by a first given voltage and a second given voltage.
In one embodiment, the first coordinate system q-axis gives the current iq *From torque current command iqcmd *Obtained by means of a current limiter.
In one embodiment, the feedback voltage v of the field weakening controllermObtained according to the following equation (2):
wherein v ismIs the feedback voltage of the field weakening controller, vd *Is a first given voltage, vq *Is a second given voltage.
In one embodiment, the second coordinate system gives the given current value idz *And iqz *Are all 0.
The dq coordinate system given current comprises a d-axis given current i
d *And q-axis set current i
q *Q-axis given current i
q *Commanded by torque current i
qcmd *Obtained by means of a current limiter. d-axis given current i
d *Obtained by means of a flux weakening control, the voltage in the flux weakening controlThe feedback being a first given voltage using the alpha-beta sub-plane
And a second given voltage
Feedback voltage v
mBy applying a first given voltage to the alpha-beta sub-plane
And a second given voltage
Obtained by the formula (2). dqz coordinate system given current i
dz *And i
qz *All the current values are 0, in the traditional double three-phase permanent magnet synchronous motor flux weakening control method, each set of three-phase winding adopts an independent flux weakening controller, and voltage feedback of an alpha-beta coordinate system of each three-phase winding is adopted, flux weakening currents can be different and comprise fifth harmonic voltage and seventh harmonic voltage, and meanwhile, the same torque current instruction i
qcmd *Different q-axis current settings may eventually be generated by two different current limiters. Therefore, the traditional method for controlling the field weakening of the double three-phase permanent magnet synchronous motor has the defects of current imbalance and current harmonic.
In one embodiment, the first coordinate system gives the current d-axis given value id *The current i is given to the q axis of the first coordinate system by weak magnetic controlq *From torque current command iqcmd *Obtained by a current limiter; given current given value i of second coordinate systemdz *And iqz *Are all 0.
In the traditional double three-phase permanent magnet synchronous motor flux weakening control method, flux weakening currents given by dq coordinate systems of two sets of three-phase motor windings are respectively obtained through two independent flux weakening controllers, but in the embodiment of the invention, the flux weakening currents given by the dq coordinate systems of the two sets of three-phase motor windings are obtained through flux weakening control under an alpha-beta sub-plane dq coordinate system.
106, performing vector control on the first given voltage, the second given voltage, the third given voltage and the fourth given voltage to reverse TparkTransformation and inverse TdqzAnd converting to obtain a fifth given voltage, a sixth given voltage, a seventh given voltage and an eighth given voltage.
A first given voltage
And a second given voltage
By vector control of inverse T
parkConverted to obtain a fifth given voltage
And a sixth given voltage
A third given voltage
And a fourth given voltage
By reversing T
dqzConverted to obtain a seventh given voltage
And an eighth given voltage
Step 107, carrying out spatial decoupling inverse transformation on the fifth given voltage, the sixth given voltage, the seventh given voltage and the eighth given voltage to obtain given value parameters of each phase voltage of the double three-phase permanent magnet synchronous motor;
a fifth given voltage
A sixth given voltage
A seventh given voltage
And an eighth given voltage
And carrying out spatial decoupling inverse transformation to obtain given value parameters of each phase voltage of the double three-phase permanent magnet synchronous motor. And the space decoupling inverse transformation is the inverse matrix transformation of the space decoupling transformation formula (1) matrix.
In one embodiment, the spatial decoupling inverse transformation is performed on a fifth given voltage, a sixth given voltage, a seventh given voltage and an eighth given voltage to obtain given value parameters of voltages of each phase of the dual three-phase permanent magnet synchronous motor, and the method further includes:
the given voltage provided by the second harmonic sub-plane is a zero-sequence voltage with a reference value of 0.
A fifth given voltage
A sixth given voltage
A seventh given voltage
And an eighth given voltage
Carrying out space decoupling inverse transformation to obtain given value parameters of each phase voltage of the double three-phase permanent magnet synchronous motor, carrying out space decoupling inverse transformation to obtain inverse matrix transformation of a space decoupling transformation formula (1) matrix, wherein the given voltage further comprises o
1-o
2Given voltage of the sub-plane due to o
1-o
2The given voltage of the sub-plane is zero sequence voltage, so o
1-o
2 Voltage reference value 0, v of the sub-plane
o1 *=v
o2 *=0。
And step 108, driving the switching device of the inverter by the given value parameter of each phase voltage of the double three-phase permanent magnet synchronous motor through a PWM (pulse width modulation) technology.
The given value parameter of each phase voltage of the double three-phase permanent magnet synchronous motor is respectively
In one embodiment, as shown in fig. 2, a flow chart of the flux weakening control of the dual three-phase permanent magnet synchronous motor based on space vector decoupling is shown.
Based on the vector space decoupling theory, the double three-phase permanent magnet synchronous motor is mapped to a six-dimensional plane. Respectively alpha-beta sub-plane, z1-z2Sub-planes and o1-o2A sub-plane. Six-phase stator current i of double three-phase permanent magnet synchronous motor is collecteda、ib、ic、ix、iy、izThrough formula (1) space decoupling transformation matrix [ T ]6]The six-phase stator current ia、ib、ic、ix、iy、izTransformed to three sub-planes for conversion to sub-plane currents, respectively alpha-beta sub-plane currents iα、iβ,z1-z2Sub-plane current iz1、iz2、o1-o2Sub-plane current io1、io2Wherein two sets of windings of the double three-phase permanent magnet synchronous motor are isolated from each other by neutral points, so1-o2The sub-planes have no current. Wherein, formula (1) is:
fundamental waves and 12k +/-1 (k is 1, 2, 3 …) subharmonics in the stator current of the motor are distributed on an alpha-beta sub-plane, and 6k +/-1 (k is 1, 3, 5 …) subharmonics are distributed on a z-beta sub-plane1-z2Sub-plane, 6 k. + -.3(k-1, 3, 5 …) subharmonic distribution at o1-o2A sub-plane. Since the fifth and seventh harmonics are mapped to z1-z2The sub-plane is not the alpha-beta sub-plane, and the alpha-beta sub-plane voltage can be used for voltage feedback in the field weakening control of the double three-phase permanent magnet motor according to the characteristic.
Alpha-beta sub-plane current iα、iβBy the formula (3) TparkTransforming to dq coordinate system to obtain feedback current i of dq coordinate systemd、iq,z1-z2Sub-plane current iz1、iz2By the formula (4) TdqzTransforming to dqz coordinate system to obtain dqz coordinate system feedback current idz、iqz. Wherein, the formula (3) and the formula (4) are:
in particular where thetaeIs the rotor electrical angle, Fd、FqIs a component in an alpha-beta sub-plane under a dq coordinate system of the double three-phase permanent magnet synchronous motor, Fdz、FqzIs z under a double three-phase permanent magnet synchronous motor dqz coordinate system1-z2Component in the sub-plane, Fα、FβIs a component in an alpha-beta sub-plane of the double three-phase permanent magnet synchronous motor, Fz1And Fz2Is z1-z2Component in the sub-plane. F may be the stator resistance RsStator voltage v, stator current i, stator flux linkage ΨsOr a permanent magnetic linkage Ψf。
dq coordinate system given current i
d *Is obtained by weak magnetic control, and the q axis of the first coordinate system gives a current i
q *From torque current command i
qcmd *Obtained by means of a current limiter, dqz coordinate system gives a current i
dz *And i
qz *Are all 0. The dq coordinate system is given a current i
d *And i
q *Feedback current i with dq coordinate system
d、i
qCalculating the difference by a proportional-integral regulator to obtain a given voltage
And a given voltage
The difference between the dqz coordinate system given current and the dqz coordinate system feedback current is calculated by a formula (5) proportional resonant regulator to obtain a given voltage
And a given voltage
Wherein the proportional resonant regulator of formula (5) is G
PR6(s), the expression of which is:
wherein KpAnd KIProportional coefficient and resonance coefficient, omega, of the proportional resonance controller, respectivelycTo cut-off frequency, ω6The proportional resonant controller has maximum gain at the resonant point and no phase lag at the resonant frequency which is equal to the six-time multiplication of the fundamental wave electric frequency of the motor, and the resonant point can be adjusted in real time according to the motor frequency.
FIG. 2 shows on the left part a field weakening controller, with dq coordinate system giving current i
d *Is obtained by weak magnetic control, and a dq coordinate system gives a current i
q *From torque current command i
qcmd *Obtained by means of a current limiter. Output voltage v of alpha-beta sub-plane under dq coordinate system
d *、v
q *The amplitude feedback voltage has an amplitude of
d-axis current set value i
d *Limited by voltage amplitude v
m *And the output voltage v
mIs obtained by adjusting a proportional-integral controller when the output voltage v is
mLess than v
m *When i is
d *0; when the output voltage v is
mGreater than v
m *When i is
d *Is less than 0. Given value of q-axis current i
q *From torque current command i
qcmd *Obtained by a current limiter whose value is defined by a current maximum value I
maxSquare of minus d-axis current set value i
d *The square root number of (a). In particular to
A given voltage to be obtained
And a given voltage
By the formula (3) T
parkInverse transformation of (a) to obtain a given voltage
And a given voltage
A given voltage to be obtained
And a given voltage
By the formula (4) T
dqzInverse transformation of (a) to obtain a given voltage
And a given voltage
Because two sets of windings of the double three-phase permanent magnet synchronous motor are isolated from neutral points, the motor has the advantages of high efficiency, low cost and high efficiency
1-o
2Voltage reference value of the sub-plane is v
o1 *=v
o2 *=0。
A given voltage to be obtained
v
o1 *、v
o2 *A space decoupling transformation matrix [ T ] through a formula (1)
6]Obtaining the reference value of each phase voltage of the double three-phase permanent magnet synchronous motor by inverse transformation
The switching devices of the inverter are driven through a PWM modulation technique.
Fig. 4a is a schematic diagram showing the sixth harmonic voltage content in the voltage feedback of the two sets of dq coordinate system in the conventional field weakening control and the conventional field weakening control.
Fig. 4b schematically shows a diagram of the current content of the 6 th harmonic in the d-axis current feedback in the conventional field weakening control and the d-axis current feedback in the conventional field weakening control.
Fig. 4c schematically shows a diagram of the current content of the 6 th harmonic in the q-axis current feedback in the conventional field weakening control and the q-axis current feedback in the conventional field weakening control.
FIG. 5a is a schematic diagram showing the voltage feedback and the six-order harmonic voltage content of the weak magnetic control method in the voltage feedback in two sets of dq coordinate systems during weak magnetic control.
Fig. 5b schematically shows a d-axis current feedback of the field weakening control method and a 6 th harmonic current content in the d-axis current feedback of the field weakening control method.
Fig. 5c schematically shows a q-axis current feedback of the field weakening control method and a schematic diagram of the 6 th harmonic current content of the field weakening control method in the q-axis current feedback.
Compared with the prior art, the embodiment of the invention has the following advantages:
the first advantage is that: in order to compare the advantages and disadvantages of the conventional flux weakening control method and the proposed flux weakening control method, the experimental results are shown in fig. 4 and 5, respectively. The magnitude of the output feedback voltage is shown in fig. 4(a) and 5 (a). The results show that the sixth harmonic voltage in fig. 5(a) is lower than that in fig. 4 (a). Therefore, in consideration of harmonic voltage and inverter nonlinearity, the margin of the reserve voltage can be smaller in the linear PWM operation, thereby improving the maximum output voltage reference value and power capacity.
The second advantage is that: FIGS. 4(b) and 5(b) show d-axis currents and corresponding FFT analysis, comparing fig. 4(b) to i in FIG. 5(b)d1And id2The 6 th harmonic in (a) is negligible. i.e. id1And id2Is the same, and i of FIG. 4(b)d1And id2The average values are not equal, and the phenomenon of current imbalance occurs. FIG. 5(c) shows iq1And iq2The two windings are basically the same, so the flux weakening control decoupled according to the space vector provided by the invention has good current balance degree for the two sets of three-phase windings.
Therefore, the field weakening control method provided by the invention is superior to the traditional field weakening control of the double three-phase permanent magnet synchronous motor in the aspects of restraining the current unbalance degree and restraining the dq axis six-order harmonic current.
In one embodiment, as shown in fig. 3, there is provided an apparatus for flux weakening control of a dual three-phase permanent magnet synchronous motor, configured to perform the method for flux weakening control of a dual three-phase permanent magnet synchronous motor in any one of the above embodiments.
Specifically, the device for controlling the field weakening of the double three-phase permanent magnet synchronous motor is a double three-phase permanent magnet synchronous motor. The rotor of the double three-phase permanent magnet synchronous motor is a permanent magnet, and the stator winding is connected by two sets of Y-shaped windings which are respectively A, B, C phases and X, Y, Z phases;
two sets of three-phase windings of the stator winding have a spatial difference of 30 degrees in electrical angle, each set of windings is powered by a set of three-phase two-level inverter, and the inverter switching device is an IGBT.
Since the fundamental component is projected onto the α - β sub-plane, the output voltage of the inverter is mostly derived from the fundamental component in the α - β sub-plane, and can be used for voltage feedback in the weak magnetic control. Because the alpha-beta sub-plane has no 5 th harmonic and 7 th harmonic, the weak magnetic reference current is more favorably generated. Meanwhile, q-axis currents generated by the same weak magnetic currents of the two sets of windings are also the same, so that the currents of the two sets of three-phase windings of the double three-phase permanent magnet synchronous motor are naturally balanced.