CN110011581B - Method and system for suppressing common mode noise of asymmetric six-phase AC motor - Google Patents

Abstract

The invention discloses a method and system for suppressing common mode noise of an asymmetric six-phase alternating current motor. phase, so that the two sets of three-phase inverters driving the asymmetric six-phase AC motor output common mode voltages with opposite amplitudes, so as to eliminate the total common mode voltage input by the inverter to the asymmetric six-phase AC motor, thereby suppressing the The common mode noise generated by the symmetrical six-phase motor; at the same time, the control method and system of the present invention do not need to add hardware, and can be realized only by improving the software algorithm.

Description

Method and system for suppressing common mode noise of asymmetric six-phase AC motor

technical field

The invention belongs to the technical field of motor control, and more particularly, relates to a method and system for suppressing common mode noise of an asymmetric six-phase AC motor.

Background technique

Compared with the three-phase AC motor, the asymmetric six-phase motor can increase the motor capacity due to the increase in the number of phases; at the same time, the asymmetric six-phase motor can eliminate the torque ripple caused by the 5th and 7th harmonics in the three-phase motor, reduce the Torque pulsation of small motors; in addition, asymmetric six-phase motors have more control degrees of freedom, which can realize fault-tolerant operation of motors under phase loss and faults, and improve system reliability. Based on the above characteristics, asymmetric six-phase AC motors are widely used in fields with high power and high reliability requirements such as ship electric propulsion, aerospace and electric vehicles.

Since the variable frequency speed regulation function of the motor drive system is realized by the pulse width modulation technology combined with the high speed switch of the inverter, the neutral point of the motor winding has a common mode voltage characterized by a high frequency pulse sequence. The common-mode voltage generates high-frequency common-mode current through the stray capacitance between the motor winding and the casing or bearing and the motor grounding, which increases the electromagnetic interference noise of the system, and at the same time causes continuous damage to the motor bearings and other components, thereby shortening the Extending the service life of the motor is one of the main problems in the motor drive.

SUMMARY OF THE INVENTION

In view of the above defects or improvement requirements of the prior art, the present invention provides a method for suppressing common mode noise of an asymmetric six-phase AC motor, aiming at solving the problem of electromagnetic interference noise in the system caused by the existence of a common mode voltage in the asymmetric six-phase AC motor Increase, the motor parts are continuously damaged, which in turn leads to the problem of shortening the service life of the motor.

In order to achieve the above purpose, the present invention provides a method for suppressing common mode noise of an asymmetric six-phase AC motor, comprising the following steps:

(1) Collect the rotor position angle θ, the DC voltage signal V _dc and the driving currents i _abc and i _uvw for driving the asymmetric six-phase AC motor;

(2) According to the rotor position angle θ and the drive currents i _abc , i _uvw , obtain the reference voltage _Vabc of each phase of the first three-phase inverter and the reference voltage of each phase of the second three-phase inverter in the static coordinate system voltage V _uvw ;

(3) Obtain the first three-phase inverter according to the reference voltage V _abc of each phase of the first three-phase inverter, the reference voltage V _uvw of each phase of the second three-phase inverter, and the DC voltage signal V _dc . the initial pulse width modulation signal G _abc of each phase of the inverter and the initial pulse width modulation signal G _uvw of each phase of the second three-phase inverter;

(4) According to the interval in which the rotor position angle θ is located, the initial pulse width modulation signal G _abc of each phase of the first three-phase inverter and the initial pulse width of each phase of the second three-phase inverter are respectively The modulation signal G _uvw is phase-shifted to obtain target pulse modulation signals PWM1-6 that make the first three-phase inverter and the second three-phase inverter output common-mode voltages with opposite amplitudes; PWM1-3 use In order to control the switch tube of the first three-phase inverter, PWM4-6 is used to control the switch tube of the second three-phase inverter.

Further, the division method of the interval described in the step (4) is:

Comparing the duty ratios of the initial pulse width modulation signals G _abc of each phase of the first three-phase inverter, the maximum and minimum duty ratios are obtained as d _{abc_max} and d _{abc_min respectively} ;

Comparing the duty ratios of the initial pulse width modulation signals G _uvw of each phase of the second three-phase inverter, the maximum and minimum duty ratios are obtained as d _{uvw_max} and d _{uvw_min respectively} ;

Divide the rotor position angle range satisfying d _{abc_max} +d _{uvw_min} >1 and d _{uvw_max} +d _{abc_min} >1, or satisfying d _{abc_max} +d _{uvw_min} <1 and d _{uvw_max} +d _{abc_min} <1 into the same section.

Preferably, the division result of the interval is:

Further, the method for phase shifting described in the step (4) is:

Keeping the initial pulse width modulation signal with the largest or the smallest duty cycle in any three-phase inverter in the interval where the rotor position angle θ is located, the first target pulse width modulation signal is obtained;

According to the principle that the target PWM signals of each phase of the first three-phase inverter and the second three-phase inverter are interleaved and canceled, while ensuring that the PWM signals with the largest or smallest duty cycle are not adjacent to each other, Select the non-maximum or non-minimum initial PWM signal in another three-phase inverter, so that its rising edge is aligned with the falling edge of the target PWM signal obtained after phase shifting, and the second target PWM signal is obtained. wide modulation signal;

According to the above method, phase-shift the initial pulse width modulation signal G _abc of each phase of the first three-phase inverter and the initial pulse width modulation signal G _uvw of each phase of the second three-phase inverter, so that each The common mode voltage of the three-phase inverter maintains the same (000) or (111) zero vector state at the beginning and end of each switching cycle, thereby obtaining the target pulse modulation signals PWM1-6.

The present invention also provides a drive system for suppressing common mode noise of an asymmetric six-phase AC motor by applying the above method, comprising: an inverter unit, a position sampling unit, a current sampling unit, a voltage sampling unit and a controller unit;

The inverter unit includes a first three-phase inverter and a second three-phase inverter, and the first three-phase inverter and the second three-phase inverter are connected to the asymmetric six-phase AC motor, and use for inverting the direct current into alternating current, and driving the asymmetric six-phase alternating current motor to work;

The input end of the position sampling unit is connected to the asymmetric six-phase AC motor, and is used for collecting the rotor position angle θ of the asymmetric six-phase AC motor;

The input end of the current sampling unit is connected to the output end of the inverter unit, and is used for collecting six-phase alternating current signals i _abc and i _uvw for driving the asymmetric six-phase alternating current motor to work;

The input terminal of the voltage sampling unit is connected to the positive and negative terminals of the DC side of the inverter unit, and is used for collecting the DC voltage signal V _dc of the DC side of the inverter unit;

The first input end of the controller unit is connected to the output end of the voltage sampling unit, the second input end is connected to the output end of the current sampling unit, and the third input end is connected to the output end of the position sampling unit , for outputting the target pulse width modulation signal according to the rotor position signal θ, the DC voltage signal V _dc and the six-phase AC current signals i _abc , i _uvw , to control the first three-phase inverter and the second three-phase inverter The inverter outputs a common-mode voltage with opposite amplitude in real time.

Further, the two sets of stator windings of the asymmetric six-phase AC motor are connected in a star shape, and the fundamental wave potentials of the three windings of each set of stator windings are 120° electrical angle difference from each other, and the difference between the two sets of windings is 30°. Electrical angle, the neutral points of the two sets of stator windings can be kept connected or disconnected;

The asymmetric six-phase AC motor may include an induction motor and a permanent magnet synchronous motor, etc., for converting electrical energy into mechanical energy for output.

In general, compared with the prior art, the following beneficial effects can be achieved through the above technical solutions conceived by the present invention:

(1) On the basis of the traditional SPWM modulation method, the present invention performs pulse phase shifting in each sector of vector synthesis, so that two sets of three-phase inverters can output common mode voltages with opposite amplitudes in real time, so as to eliminate the inverter The total common mode voltage input to the asymmetric six-phase AC motor can be eliminated, thereby eliminating the common mode noise generated by the asymmetric six-phase motor.

(2) The control method of the present invention does not need to increase the hardware, and can be realized only by improving the software algorithm. It has strong versatility, can protect the motor bearing and improve the reliability of the system.

Description of drawings

1 is a flowchart of a common mode noise suppression method of the present invention;

FIG. 2 is a flow diagram of signals involved in the common mode noise suppression method of the present invention;

Fig. 3 is the pulse width modulation signal waveform diagram that obtains according to the traditional pulse width modulation algorithm;

4 is an interval division diagram of the common mode noise suppression method according to the present invention;

Figure 5-8 is a waveform diagram of the target PWM signal obtained according to the inventive common mode noise suppression method;

9 is a comparison diagram of a common mode voltage generated according to the common mode noise suppression method of the present invention and a common mode voltage generated according to a traditional modulation algorithm;

10 is a comparison diagram of the common mode current generated according to the common mode noise suppression method of the present invention and the common mode current generated according to the traditional modulation algorithm;

11 is a schematic diagram of the physical composition of the drive system according to the present invention;

1 is an inverter unit, 2 is an asymmetric six-phase motor, 3 is a position sampling unit, 4 is a current sampling unit, 5 is a voltage sampling unit, and 6 is a controller unit.

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.

The present invention provides a method and system for suppressing common mode noise of an asymmetric six-phase alternating current motor, the purpose of which is to suppress common mode noise of an asymmetric six-phase alternating current motor system, protect motor bearings and improve system reliability.

Referring to FIG. 1 , a method for suppressing common mode noise of an asymmetric six-phase AC motor provided by the present invention includes the following steps:

(1) Calculate the reference voltage of each phase of the first three-phase inverter and the reference voltage of each phase of the second three-phase inverter under the static coordinate system through the traditional space vector decoupling control method;

Specifically, referring to FIG. 2 , the collected rotor position angle θ is derived to obtain the real-time angular velocity w of the rotor of the asymmetric six-phase AC motor, and the difference between w and the angular velocity reference signal w _ref is obtained to obtain the angular velocity error signal w _{_err} , Perform PI control on _{w_err} to obtain q-axis reference current i _qref , d-axis, z ₁ -axis and z ₂ -axis reference current _idref , _iz1ref and _iz2ref can be set according to actual needs;

collecting six-phase currents i _a , i _b , i _c , i _u , i _v and i _w currently used by the first three-phase inverter and the second three-phase inverter to drive the asymmetric six-phase AC motor, Coordinate transformation is performed on the six-phase current to obtain the actual currents id , i _q , _iz1 and _iz2 of the _d , q, z ₁ and z ₂ axes under the rotating coordinate system;

The specific transformation method can be realized by the following transformation formula:

Obtain the difference signals _{id_err} , i _{q_err} , _{iz1_err} and _{iz2_err} corresponding to the _actual currents id , i _q , _iz1 and _iz2 and the reference currents _idref , i _qref , _iz1ref and _iz2ref , The difference signals are respectively controlled by PI to obtain the reference voltages V _d , V _q , V _z1 and V _z2 of the d-axis, q-axis, z ₁ and z ₂ axes;

Coordinate transformation is performed on the reference voltages V _d , V _q , V _z1 and V _z2 to obtain six-phase reference voltages V _a , V _b , V _c , V _u , V _v , and V _w in the static coordinate system;

The specific transformation method can be realized by the following formula:

(2) Obtain symmetrical initial sinusoidal pulse width modulation signals Ga, Gb, Gc, Gu, Gv and Gw through the traditional SPWM sinusoidal pulse width modulation algorithm;

Specifically, the six-phase reference voltage is divided by the DC voltage signal V _dc to obtain the normalized reference voltage of each phase of the first three-phase inverter and the second three-phase inverter, and the normalized reference voltage is The voltages are compared with the triangular carrier in amplitude respectively to generate the initial symmetrical sinusoidal pulse width modulation signals Ga, Gb, Gc, Gu, Gv and Gw as shown in Figure 3, where Ga, Gb and Gc are used to drive the first three-phase inverter. The pulse of the inverter switch tube action, Gu, Gv and Gw are the pulses that drive the action of the second three-phase inverter switch tube, U _cm1 and U _cm2 are the common mode voltages output by the two sets of inverters, it can be seen that the two The real-time amplitude of the common-mode voltage output by the set of inverters is not opposite, which will generate a common-mode current in the asymmetric six-phase AC motor.

(3) dividing the rotor position angle into intervals according to the duty cycle of the initial sinusoidal pulse width modulation signal;

Specifically, in order to determine the principle and basis of the interval division, it is necessary to clarify the effect achieved after the phase shift of each phase pulse and the corresponding phase shift requirements:

First, both the first three-phase inverter and the second three-phase inverter need to keep two zero-vector switching states of (000) and (111), so that the common-mode voltage of each three-phase inverter is When the neutral points of the two sets of windings of the asymmetric six-phase motor are separated, more level states are output to realize the optimization of the level state of the phase voltage and reduce the current ripple of the phase current;

In addition, the common mode voltage of each three-phase inverter maintains the same (000) or (111) zero vector state at the beginning and end of each switching cycle, ensuring that the pulse starting state of all bridge arms is unchanged, thereby eliminating the need for The process of judging the initial state of the pulse after phase-shifting simplifies the complexity of the method implementation;

Under the condition that the above two requirements are met and the common-mode voltages of the first three-phase inverter and the second three-phase inverter are canceled, the zero vector of the common-mode voltages of the two sets of three-phase inverters can be determined. There is a direct relationship between the duty cycle and the maximum and minimum duty cycles of the PWM signals of the two three-phase inverters, so the interval can be divided according to the relationship between the zero vector duty cycle and the duty cycle of different-phase PWM signals;

The expression of the duty cycle of each phase PWM signal obtained by the sinusoidal pulse width modulation method is:

Among them, da , _{db , dc , d u , d v ,} and d _w are the duty ratios of the PWM signals of each phase, m is the modulation coefficient, and θ is the rotor position angle;

According to the above expression, compare the duty ratios of the Ga, Gb and Gc to obtain the maximum and minimum duty ratios of the PWM signal in the first three-phase inverter as d _{abc_max} and d _{abc_min respectively} ; compare Gu, Gv and The size of the duty cycle of Gw, the maximum and minimum duty cycles of the PWM signal in the second three-phase inverter are obtained as d _{uvw_max} and d _{uvw_min respectively} ;

Compare the relationship between the sum of the maximum and minimum duty cycles and 1 between the two inverters;

When d _{abc_max} +d _{uvw_min} >1 and d _{uvw_max} +d _{abc_min} >1, the (000) zero vector duty cycle of the ABC phase PWM signal after phase shifting must be 1-d _{abc_max} , (111) zero vector duty The ratio must be 1-d _{uvw_max} , and the two zero vector duty cycles of the UVW phase PWM signal after phase shifting are exactly opposite to the ABC phase;

When d _{abc_max} +d _{uvw_min} <1 and d _{uvw_max} +d _{abc_min} <1, the (000) zero vector duty cycle of the ABC-phase PWM signal after phase shifting must be d _{uvw_min} , and the (111) zero vector duty cycle must be is d _{abc_min} , and the two zero vector duty cycles of the UVW phase PWM signal after phase shifting are exactly opposite to the ABC phase;

It can be seen that the relationship between the sum of the maximum and minimum duty cycles between the first three-phase inverter and the second three-phase inverter and 1 can determine the duty cycle of the output zero vector of the two inverters, so it can be as a criterion for dividing the interval;

The result of interval division is shown in Figure 4:

其中，θ表示所述转子位置角度。

where θ represents the rotor position angle.

(4) According to the interval in which the rotor position angle is located, phase-shift the initial PWM signal to obtain a target PWM signal, so that the first three-phase inverter and the second three-phase inverter output Common-mode voltages of opposite magnitudes to cancel common-mode noise generated by asymmetric six-phase AC motors.

Specifically, the principle of phase shifting is as follows:

1) The three-phase pulse signal that drives the switching operation of the first three-phase inverter (hereinafter referred to as: ABC three-phase pulse) and the three-phase pulse signal that drives the switching operation of the third three-phase inverter (hereinafter referred to as UVW three-phase pulse) ) must be staggered and canceled. If there are switch cancellations in the same set of windings, the switch combination state of the three-phase inverter output zero vector cannot be realized;

2) When the PWM signal with the largest duty cycle in any three-phase inverter is used as the starting pulse, the PWM signals with the largest duty cycle in the two three-phase inverters cannot be adjacent to each other. For example, the A phase is ABC three. The pulse signal with the largest duty cycle among the phase pulses, the U phase is the pulse signal with the largest duty cycle among the three-phase pulses, then the A phase and the U phase cannot be adjacent; when the duty cycle of any three-phase inverter is the smallest When the PWM signal is the start pulse, the PWM signal with the smallest duty cycle in the two three-phase inverters cannot be adjacent. For example, the C phase is the pulse signal with the smallest duty cycle among the ABC three-phase pulses, and the W phase is the three-phase pulse. The pulse signal with the smallest duty cycle in the pulse, the C phase and the W phase cannot be adjacent; if the above two requirements are not met, the initial state of some PWM signals will change with the rotor angle, and the two three-phase inverse conditions cannot be satisfied. The inverter always maintains the state of outputting two zero vectors;

Fig. 5 is a schematic diagram of the target PWM signal obtained after the initial PWM signal is phase-shifted according to the above-mentioned principle in the first interval, and the phase-shifting steps are as follows:

The target pulse width modulation signal PWM1 is obtained by keeping the A-phase PWM signal Ga as the phase-shifted reference signal unchanged;

Select the V-phase PWM signal Gv as the second phase-shift signal, and move Gv to align the rising edge of Gv with the falling edge of PWM1 to obtain the target PWM signal PWM5;

Move Gc to align the rising edge of Gc with the falling edge of PWM5 to obtain the target PWM signal PWM3;

Move Gu to align the rising edge of Gu with the falling edge of PWM3 to obtain the target PWM signal PWM4;

Move Gb to align the rising edge of Gb with the falling edge of PWM4 to obtain the target PWM signal PWM2;

Move Gw to align the rising edge of Gw with the falling edge of PWM2 to obtain the target PWM signal PWM6;

After the above-mentioned phase-shifting method is adopted, it can be ensured that the common-mode voltages of the two inverters in the first sector remain opposite, thereby suppressing the common-mode noise of the asymmetric six-phase motor;

In addition, there are other phase shifting methods in this interval. As shown in Figure 6, the phase shifting sequence is: A-W-C-U-B-V-A; the phase shifting sequence shown in Figure 7 is: A-V-B-U-C-W-A; the phase shifting sequence shown in Figure 8 is: A-W-B-U-C-V-A; Figure 5- The target pulse signals shown in 8 can all achieve the same common mode rejection effect. Following the phase-shifting principle in other sectors, a variety of phase-shifting methods can also be derived to achieve common-mode rejection.

Fig. 9 is a comparison of the common mode voltage between the traditional modulation algorithm and the common mode noise suppression algorithm proposed by the present invention under the same working conditions. It can be seen that the traditional modulation algorithm generates a large common mode voltage in the motor, while the traditional modulation algorithm The common mode noise suppression algorithm can eliminate the total mode voltage of the motor.

Figure 10 is a comparison of the common mode current between the general modulation algorithm and the common mode noise suppression algorithm proposed by the present invention under the same working conditions. The common mode noise suppression algorithm can realize the elimination of the total mode current of the motor.

As shown in FIG. 11 , the present invention also provides a drive system for common mode noise of an asymmetric six-phase AC motor, including: an inverter unit 1 , a position sampling unit 3 , a current sampling unit 4 , a voltage sampling unit 5 and a control unit 6;

The inverter unit 1 includes a first three-phase inverter and a second three-phase inverter, the first three-phase inverter and the second three-phase inverter are connected to the asymmetric six-phase AC motor 2, Inverting the direct current to alternating current, driving the asymmetric six-phase alternating current motor 2 to work;

The input end of the position sampling unit 3 is connected to the asymmetric six-phase AC motor 2, and is used to collect the rotor position angle θ of the asymmetric six-phase AC motor 2;

The input end of the current sampling unit 4 is connected to the output end of the inverter unit 1 for collecting the six-phase alternating current signals i _abc and i _uvw for driving the asymmetric six-phase alternating current motor 2 to work;

The input terminal of the voltage sampling unit 5 is connected to the positive and negative terminals of the DC side of the inverter unit 1, and is used for collecting the DC voltage signal V _dc of the DC side of the inverter unit 1;

The first input end of the controller unit 6 is connected to the output end of the voltage sampling unit 5, the second input end is connected to the output end of the current sampling unit 4, and the third input end is connected to the output end of the position sampling unit 3, for according to the The rotor position signal θ, the DC voltage signal V _dc and the six-phase AC current signals i _abc , i _uvw output the target pulse width modulation signal, and control the real-time output amplitude of the first three-phase inverter and the second three-phase inverter. value of the opposite common-mode voltage.

The two sets of stator windings of the asymmetric six-phase AC motor 2 are connected in a star shape, and the fundamental wave potentials of the three windings of each set of stator windings are 120° electrical angle difference from each other, and the difference between the two sets of windings is 30° electrical angle. The neutral point of the stator winding can be kept connected or disconnected;

The asymmetric six-phase AC motor 2 may include an induction motor and a permanent magnet synchronous motor, etc., for converting electrical energy into mechanical energy for output.

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 (3)

1. A method for suppressing common mode noise of an asymmetric six-phase alternating current motor is characterized by comprising the following steps:

(1) collecting rotor position angle theta, DC voltage signal V_dcAnd a drive current i for driving the asymmetrical six-phase AC motor_abc、i_uvw；

(2) According to the rotor position angle theta and the driving current i_abc、i_uvwObtaining the reference voltage V of each phase of the first three-phase inverter under the static coordinate system_abcAnd each phase reference voltage V of the second three-phase inverter_uvw；

(3) According to the reference voltage V of each phase of the first three-phase inverter_abcReference voltage V of each phase of the second three-phase inverter_uvwAnd said direct voltage signal V_dcObtaining initial pulse width modulation signals G of each phase of the first three-phase inverter_abcAnd each phase initial pulse width modulation signal G of the second three-phase inverter_uvw；

(4) According to the interval of the rotor position angle theta, respectively carrying out initial pulse width modulation signals G on each phase of the first three-phase inverter_abcAnd each phase initial pulse width modulation signal G of the second three-phase inverter_uvwPerforming phase shifting to obtain a target pulse width modulation signal PWM1-6 which enables the first three-phase inverter and the second three-phase inverter to output common-mode voltages with opposite amplitudes; wherein PWM1-3 is used for controlling the first three-phase inverter switch tube, and PWM4-6 is used for controlling the second three-phase inverter switch tube; the interval dividing method in the step (4) comprises the following steps:

comparing the initial pulse width modulation signals G of each phase of the first three-phase inverter_abcThe maximum and minimum duty ratios obtained are d_{abc_max}And d_{abc_min}；

Comparing the initial pulse width modulation signals G of each phase of the second three-phase inverter_uvwThe maximum and minimum duty ratios obtained are d_{uvw_max}And d_{uvw_min}；

Will satisfy d_{abc_max}+d_{uvw_min}>1 and d_{uvw_max}+d_{abc_min}>1, or satisfy d_{abc_max}+d_{uvw_min}<1 and d_{uvw_max}+d_{abc_min}<1 dividing the rotor position angle range into one and the sameAn interval; the result of the division of the intervals is:

the phase shifting method comprises the following steps:

keeping the initial pulse width modulation signal with the maximum or minimum duty ratio in any three-phase inverter in the interval of the rotor position angle theta unchanged to obtain a first target pulse width modulation signal;

according to the principle that target pulse width modulation signals of each phase of the first three-phase inverter and the second three-phase inverter are staggered and offset, and pulse width modulation signals with the maximum or minimum duty ratios are not adjacent, selecting a non-maximum or non-minimum initial pulse width modulation signal in the other three-phase inverter, and aligning the rising edge of the initial pulse width modulation signal with the falling edge of the previous target pulse width modulation signal obtained after phase shifting to obtain a next target pulse width modulation signal;

according to the mode, the initial pulse width modulation signals G are respectively sent to all phases of the first three-phase inverter_abcAnd each phase initial pulse width modulation signal G of the second three-phase inverter_uvwAnd performing phase shifting to enable the head-to-tail state of each three-phase inverter common-mode voltage in each switching period to keep the same (000) or (111) zero vector state, thereby obtaining the target pulse width modulation signal PWM 1-6.

2. A drive system for suppressing common mode noise of an asymmetric six-phase ac motor using the method of claim 1, comprising: the device comprises an inverter unit (1), a position sampling unit (3), a current sampling unit (4), a voltage sampling unit (5) and a controller unit (6);

the inverter unit (1) comprises a first three-phase inverter and a second three-phase inverter, wherein the first three-phase inverter and the second three-phase inverter are connected with the asymmetric six-phase alternating current motor and are used for inverting direct current into alternating current and driving the asymmetric six-phase alternating current motor (2) to work;

the input end of the position sampling unit (3) is connected with the asymmetric six-phase alternating current motor (2) and is used for acquiring a rotor position angle theta of the asymmetric six-phase alternating current motor (2);

the input end of the current sampling unit (4) is connected with the output end of the inverter unit (1) and is used for collecting a six-phase alternating current signal i for driving the asymmetric six-phase alternating current motor (2) to work_abcAnd i_uvw；

The input end of the voltage sampling unit (5) is connected with the positive end and the negative end of the direct current side of the inverter unit (1) and is used for acquiring a direct current voltage signal V of the direct current side of the inverter unit (1)_dc；

The first input end of the controller unit (6) is connected with the output end of the voltage sampling unit (5), the second input end is connected with the output end of the current sampling unit (4), and the third input end is connected with the output end of the position sampling unit (3) and used for generating a rotor position signal theta and a direct-current voltage signal V according to the rotor position signal theta and the direct-current voltage signal V_dcAnd six-phase AC current signal i_abc、i_uvwAnd outputting a target pulse width modulation signal to control the first three-phase inverter and the second three-phase inverter to output common-mode voltage with opposite amplitudes in real time.

3. The driving system for suppressing the common-mode noise of the asymmetric six-phase alternating-current motor as claimed in claim 2, wherein two sets of stator windings of the asymmetric six-phase alternating-current motor are connected in a star shape, the three winding fundamental wave potentials of each set of stator windings are different from each other by 120 degrees in electrical angle, the two sets of windings are different from each other by 30 degrees in electrical angle, and neutral points of the two sets of stator windings can be connected or disconnected.

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