Dual three-phase motor harmonic suppression method based on discrete resonance module

Abstract

The invention discloses a dual three-phase motor harmonic suppression method based on a discrete resonance module, and belongs to the field of motor driving control. The method comprises the following steps: firstly, modeling a neutral-point-isolated dual three-phase motor by adopting vector space decoupling to obtain controlled object models of a torque plane and a harmonic plane; secondly, designing an extended state observer based on a discrete resonance module for the decoupled harmonic plane, wherein the extended state observer is used for observing and amplifying the harmonic; and finally, compensating the harmonic voltage by adopting a dead-beat control method to complete a current closed loop. Finally, the method disclosed by the invention is implemented on the dual three-phase motor to achieve the effect of suppressing harmonic waves. From the perspective of discretization, compared with a traditional continuous control method, the method can be conveniently deployed in a conventional industrial microcontroller and is suitable for various working conditions.

Description

Technical Field

[0001] The invention belongs to the field of motor drive control of a servo drive system, and in particular relates to a dual three-phase motor harmonic suppression method based on a discrete resonance module. Background Art

[0002] The dual three-phase permanent magnet synchronous motor has the characteristics of high power density, small torque pulsation, high reliability and compact structure. At the same time, the dual three-phase permanent magnet synchronous motor is easy to process and can be adjusted in the traditional three-phase motor winding. Therefore, the research on the drive control method of the dual three-phase permanent magnet synchronous motor is of great significance. However, in practical applications, due to the small harmonic impedance including stator resistance and leakage inductance, inverter nonlinearity and air gap magnetic field distortion, the stator winding of the dual three-phase permanent magnet synchronous motor has a large harmonic current, which leads to a decrease in the electromagnetic conversion efficiency of the system and a decrease in the control performance. Therefore, suppressing harmonic current is one of the problems that need to be solved in the dual three-phase permanent magnet synchronous motor drive system.

[0003] Existing methods for suppressing harmonic currents can be divided into three categories: optimizing motor parameters, adding external filters, and innovating current control methods. Optimizing motor parameters can easily increase the time cost of motor manufacturing / design during application, and may reduce the torque / power density of the motor, and is not applicable to motors that have already been designed. For systems that are in ultra-low speed conditions for a long time, the harmonic frequency is low, and there are shortcomings such as difficulty in designing external filters, complex electromagnetic structures, and large filter components. Since the current in the harmonic plane is an alternating current, traditional proportional-integral control cannot track it without static error. The emergence of proportional resonant controllers just makes up for this deficiency, and multi-resonant controllers are widely used in dual three-phase permanent magnet synchronous motor control systems. However, the use of proportional resonant controllers faces challenges such as inaccurate resonant frequency and interference between different frequencies, which may introduce unknown resonances in the closed-loop system. Existing harmonic suppression based on observer methods does not fully consider the harmonic characteristics, and requires a compromise between control bandwidth and sensor measurement noise. Summary of the invention

[0004] In order to solve the problem mentioned in the background technology that large harmonics caused by small impedance lead to reduced system electromagnetic conversion efficiency and control performance, the present invention provides a dual three-phase motor harmonic suppression method based on a discrete resonance module.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] A method for suppressing harmonics of a dual three-phase motor based on a discrete resonance module comprises the following steps:

[0007] Step 1: Through vector space decoupling and Parker coordinate transformation, the model of the dual three-phase permanent magnet synchronous motor in the six-phase stationary coordinate system is transformed into the synchronous rotating coordinate system to obtain the harmonic distribution law of the dual three-phase motor;

[0008] Step 2: For the motor model in the synchronous rotating coordinate system, the deadbeat control method is applied in the torque plane, and a discrete extended state observer is designed in the harmonic plane. The total disturbance containing harmonic information is given through the extended state, and the relationship between the discrete and continuous observer bandwidths is given;

[0009] Step 3: Design a discrete resonant module for the fifth and seventh harmonic currents in the harmonic plane and embed it into the structure of the discrete extended state observer. After compensating for the total disturbance including harmonics, obtain the controlled object integrated by the discrete resonant module;

[0010] Step 4: For the pure integral object after adding total disturbance compensation to the harmonic plane, a deadbeat control method is designed for current closed-loop control of the dual three-phase permanent magnet synchronous motor after harmonic suppression.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] (1) Compared with the existing proportional resonant controller method, the present invention can more accurately suppress harmonic frequencies and improve the interference between different frequencies.

[0013] (2) In addition to suppressing the dominant harmonic frequency, the addition of the extended state observer can quantify the system's unmodeled dynamics and external disturbances in the form of total disturbances for feedforward.

[0014] (3) From a discrete perspective, compared with the traditional continuous control method, the proposed harmonic suppression strategy can be easily deployed in conventional industrial microcontrollers and is applicable to various working conditions.

[0015] (4) The present invention has low cost and small computational complexity, and fully utilizes the system's own conditions without adding additional cost, space, load, and power consumption to the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a control block diagram of a dual three-phase motor harmonic suppression method based on a discrete resonance module.

[0017] Figure 2 The present invention is a flow chart of a method for suppressing harmonics of a dual three-phase motor based on a discrete resonance module.

[0018] Figure 3a , Figure 3b , Figure 3c , Figure 3d This is a comparison diagram of the harmonic suppression experiment before and after the present invention, where: Figure 3aHarmonic suppression front phase current and harmonic plane current are shown; Figure 3b The harmonic analysis of phase current before harmonic suppression is shown; Figure 3c The phase current and harmonic plane current after harmonic suppression are shown; Figure 3d Shows the phase current harmonic analysis after harmonic suppression. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention, that is, the embodiments described only represent selected embodiments of the present invention, not all embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0020] like Figure 1 As shown, this embodiment relates to a dual three-phase permanent magnet synchronous motor drive system, including a reference signal generation unit, a deadbeat control method unit, an extended state observer unit integrating a discrete resonance module, a pulse width modulation unit, a position and speed detection unit, and a coordinate transformation unit. Among them, the reference signal generation unit generates a current reference value , the deadbeat control method unit generates a control signal , the pulse width modulation unit modulates the signal Generate six-phase current feedback values; the coordinate transformation unit performs vector space decoupling and Park transformation on the six-phase current to obtain the rotating coordinate system , and enter The current signal is sent to the extended state observer unit of the integrated discrete resonant module; the position and speed detection unit detects the rotor position and motor speed of the motor, and the rotor position Output to the coordinate transformation unit to convert the motor speed Output to the deadbeat control method unit; the extended state observer unit with integrated discrete resonance module outputs the observed value of the current through the internal algorithm , and the observed value of the total disturbance . pass and the total disturbance observation Get the difference.

[0021] based on Figure 1 The dual three-phase permanent magnet synchronous motor drive system shown in the figure, the present invention proposes a dual three-phase motor harmonic suppression method based on a discrete resonance module, such as Figure 2 As shown, the specific steps include:

[0022] Step 1: Through vector space decoupling and Parker coordinate transformation, the model of the dual three-phase permanent magnet synchronous motor in the six-phase stationary coordinate system is transformed into the synchronous rotating coordinate system to obtain the harmonic distribution law of the dual three-phase motor.

[0023] The model of the dual three-phase permanent magnet synchronous motor in the six-phase stationary coordinate system is expressed as:

[0024] ;

[0025] in, , , Represent the six-phase stator voltage, current and flux respectively, , , They represent stator resistance, permanent magnet flux amplitude and rotor electrical angle respectively. represents the winding flux, is the stator inductance matrix related to the stator self-leakage inductance, stator self-inductance and reluctance inductance, and the corresponding matrix is ​​expanded as:

[0026] ;

[0027] The six-phase stationary coordinate system model is transformed into the rotating coordinate system through vector space decoupling and Parker coordinate transformation. The fundamental component and harmonic order are The phase winding variables are all mapped to The moment plane, harmonic order is The phase winding variables are all mapped to Harmonic plane. Vector space decoupling matrix and Parker coordinate transformation matrix It is expressed as:

[0028] , .

[0029] The following is an example of a dual three-phase permanent magnet synchronous motor drive system. A simple analysis of its model is performed. Through vector space decoupling and Parker transformation, the mathematical model in the rotating coordinate system is obtained as follows:

[0030] ;

[0031] in, , and , Represents the moment plane Shaft voltage and current, , and , Represents the harmonic plane Shaft voltage and current, , Respectively Axis and Shaft inductance, It is the stator self-leakage inductance. Indicates the motor electrical angular velocity.

[0032] The motor parameters in the known rotating coordinate system are mH, Ω, stator self-leakage inductance mH, the pole pair number is 3.

[0033] The discrete space equation of the dual three-phase permanent magnet synchronous motor is obtained through the rotating coordinate system model:

[0034] , where k represents the kth moment;

[0035] Step 2: For the motor model in the synchronous rotating coordinate system, the deadbeat control method is applied in the torque plane, and a discrete extended state observer is designed in the harmonic plane. The total disturbance containing harmonic information is given through the extended state, and the relationship between the discrete and continuous observer bandwidths is given.

[0036] For the reference current signal , implemented as Figure 1 The control scheme shown in the figure. The torque plane uses the deadbeat control method, through the discrete voltage equation The designed control law is:

[0037] ;

[0038] in, , , , express time Shaft current and voltage, , express time Shaft current, represents the controller discrete time; , express Axis reference voltage, , Indicates the reference current signal being tracked;

[0039] Harmonic plane The discrete extended state observer is designed, and the bandwidth of the continuous observer is rad / s, sampling time s, then the discrete observer bandwidth is .

[0040] For the harmonic plane Axis dynamic equations The discrete extended state observer is designed as follows:

[0041] ;

[0042] in, , . Indicates current and the observed value of the total disturbance, represents the observer input. represents the discrete extended state observer bandwidth, and , . and the continuous extended state observer bandwidth The relationship is .in express The axes include the total disturbance of the unmodeled dynamics.

[0043] Similarly, according to Principle Design of Axis Discrete Extended State Observer Axis, get the observation status .

[0044] Step 3: Design a discrete resonant module for the fifth and seventh harmonic currents in the harmonic plane and embed it into the structure of the discrete extended state observer. After compensating for the total disturbance including harmonics, obtain the controlled object integrated by the discrete resonant module.

[0045] For the harmonic plane The discrete resonance module for the fifth and seventh harmonic currents of the shaft is designed as follows:

[0046] ;

[0047] in,

[0048] , , , , ;

[0049] in, , is the resonant module gain, is the cut-off frequency, Indicates the resonant frequency. rad / s, rad / s, rad / s. The output of the fifth resonance module And the seventh resonance module output Substitution After the axis observer system, the expression of discrete resonant observer is obtained as follows:

[0050] ;

[0051] in, , ;

[0052] in, Represents the observed value of the total disturbance after adding the resonance module.

[0053] Similarly, according to Principle Design of Axis Discrete Resonance Observer Axis, get the observation status .

[0054] Based on the following equation, the total disturbance observation value and To make compensation:

[0055] ;

[0056] Available The harmonic plane equation is:

[0057] ;

[0058] So far obtained After the harmonic plane is integrated by the discrete resonance module, the controlled object is shown in the above formula.

[0059] Step 4: For the pure integral object after adding total disturbance compensation to the harmonic plane, a deadbeat control method is designed for current closed-loop control of the dual three-phase permanent magnet synchronous motor after harmonic suppression.

[0060] For the pure integration object after the integration of the resonant module, a deadbeat control method is designed:

[0061] ;

[0062] From step 2 about , The equation for , The equation is calculated and the modulation signal is output to complete the current closed-loop control of the dual three-phase permanent magnet synchronous motor after harmonic suppression.

[0063] Figure 3a , Figure 3b , Figure 3c , Figure 3d This is a comparison diagram of the harmonic suppression experiment before and after the present invention, where: Figure 3a Harmonic suppression front phase current and harmonic plane current are shown; Figure 3b The harmonic analysis of phase current before harmonic suppression is shown; Figure 3c The phase current and harmonic plane current after harmonic suppression are shown; Figure 3d Shows the phase current harmonic analysis after harmonic suppression.

[0064] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed in the specific embodiment, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be within the scope of the concept described in the present invention, through the above teachings to change the technology or knowledge in the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A dual three-phase motor harmonic suppression method based on discrete resonance module, characterized in that: The steps include: Step 1: Through vector space decoupling and Parker coordinate transformation, the model of the dual three-phase permanent magnet synchronous motor in the six-phase stationary coordinate system is transformed into the synchronous rotating coordinate system to obtain the harmonic distribution law of the dual three-phase motor; Step 2: For the motor model in the synchronous rotating coordinate system, the deadbeat control method is applied in the torque plane, and a discrete extended state observer is designed in the harmonic plane. The total disturbance containing harmonic information is given through the extended state, and the relationship between the discrete and continuous observer bandwidths is given; Step 3: Design a discrete resonant module for the fifth and seventh harmonic currents in the harmonic plane, and embed it into the structure of the discrete extended state observer. After compensating for the total disturbance including the harmonics, obtain the controlled object integrated by the discrete resonant module. Step 4: For the pure integral object after adding total disturbance compensation to the harmonic plane, a deadbeat control method is designed for current closed-loop control of the dual three-phase permanent magnet synchronous motor after harmonic suppression.

2. The method for suppressing harmonics of a dual three-phase motor based on a discrete resonance module according to claim 1, characterized in that: In the step 1, the stator of the dual three-phase permanent magnet synchronous motor is composed of two sets of three-phase symmetrical windings connected in Y shape, and the neutral points between the two sets of windings are isolated and differ by 30 electrical degrees in space.

3. The method for suppressing harmonics of a dual three-phase motor based on a discrete resonance module according to claim 2 is characterized in that: The model of the dual three-phase permanent magnet synchronous motor in the six-phase stationary coordinate system is expressed as: ； in, , , Represent the six-phase stator voltage, current and flux respectively, , , They represent stator resistance, permanent magnet flux amplitude and rotor electrical angle respectively. is the stator inductance matrix related to the stator self-leakage inductance, stator self-inductance and reluctance inductance, and the corresponding matrix is ​​expanded as: ； The six-phase stationary coordinate system model is transformed into the rotating coordinate system through vector space decoupling and Parker coordinate transformation. The fundamental component and harmonic order are The phase winding variables are all mapped to The moment plane, harmonic order is The phase winding variables are all mapped to Harmonic plane; the mathematical model in the rotating coordinate system is as follows: ； in, , and , Represents the moment plane Shaft voltage and current, , and , Represents the harmonic plane Shaft voltage and current; , Respectively Axis and Shaft inductance, is the stator self-leakage inductance; Indicates the motor electrical angular velocity.

4. The method for suppressing harmonics of a dual three-phase motor based on a discrete resonance module according to claim 3 is characterized in that: Vector space decoupling matrix and Parker coordinate transformation matrix It is expressed as: ， 。 5. The method for suppressing harmonics of a dual three-phase motor based on a discrete resonance module according to claim 1, characterized in that: The second step comprises: For the moment plane, the voltage equation is discretized Design of deadbeat control law: ； in, , , , express time Shaft current and voltage, , express time Shaft current, represents the controller discrete time; , express Axis reference voltage, , Indicates the reference current signal being tracked; For the harmonic plane Axis dynamic equations: ； in, express The axis includes the total disturbance of the unmodeled dynamics; The discrete extended state observer is designed as follows: ； in, Indicates current and the observed value of the total disturbance, represents the observer input; represents the discrete extended state observer bandwidth, and , ; and the continuous extended state observer bandwidth The relationship is ; Similarly, according to Principle Design of Axis Discrete Extended State Observer Axis, get the observation status .

6. The method for harmonic suppression of dual three-phase motors based on discrete resonance modules according to claim 1, characterized in that: The step three comprises: The discrete resonant module is shown below: ； in, , , , , , is the resonant module gain, is the cut-off frequency, Indicates the resonant frequency.

7. The method for suppressing harmonics of a dual three-phase motor based on a discrete resonance module according to claim 6, characterized in that: The fifth resonance module output And the seventh resonance module output Substitution After the axis observer system, the expression of discrete resonant observer is obtained as follows: ； in, , , Represents the observed value of the total disturbance after adding the resonance module; in accordance with Principle Design of Axis Discrete Resonance Observer Axis, get the observation status .

8. The method for harmonic suppression of dual three-phase motors based on discrete resonance modules according to claim 7 is characterized in that: Based on the following equation, the total disturbance observation value and To make compensation: ； get The harmonic plane equation is: ； So far obtained After the harmonic plane is integrated by the discrete resonance module, the controlled object is shown in the above formula.

9. The method for suppressing harmonics of a dual three-phase motor based on a discrete resonance module according to claim 1, characterized in that: The fourth step includes: designing a deadbeat control method for the pure integration object after the integration of the resonant module: , , Indicates the xy axis reference voltage, , represents the xy axis reference current, , Represents the xy-axis current observation value.

10. The method for harmonic suppression of dual three-phase motors based on discrete resonance modules according to claim 1, characterized in that: From step 2 about , The equation for , The equation of is used to complete the current closed loop of the dual three-phase permanent magnet synchronous motor after harmonic suppression.

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