Dual-redundancy permanent magnet synchronous motor current balancing method

Abstract

The invention belongs to the technical field of motor control, and particularly relates to a dual-redundancy permanent magnet synchronous motor current equalization method, which comprises the following steps of: calculating a derivative of an integral sliding mode surface function, comparing the derivative with a derivative of a sliding mode surface designed based on an exponential approaching rate, and selecting a larger value as an error compensation signal of a dual-redundancy q-axis current value, the parameters serve as sliding film surface parameters; the sliding mode surface parameters are substituted into a Lyapunov function to verify whether a sliding mode controller is stable or not, and if yes, a q-axis voltage compensation value is calculated through the two-redundancy q-axis current and an integral sliding mode surface function; and injecting the q-axis voltage compensation value into a dual-redundancy vector closed-loop control system, and carrying out current balance control. The current balancing method based on sliding mode error compensation is provided by improving a traditional current average distribution balancing strategy, the advantages of high robustness and fast dynamic response of sliding mode control are combined, the current difference between two redundancies can be rapidly eliminated when a dual-redundancy system operates, and the purpose of current balancing is achieved.

Description

Technical Field

[0001] This application belongs to the field of motor control technology, and specifically relates to a current balancing method for a dual-redundant permanent magnet synchronous motor. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are characterized by high torque density, high power factor, high efficiency, high control precision, and low noise. Dual-redundant PMSMs, as a new type of motor with high reliability and stability, innovatively combine redundancy technology with permanent magnet synchronous motors. This not only gives them the inherent advantages of permanent magnet synchronous motors, such as a wide speed range and high power density, but also greatly improves the safety and reliability of the motor during operation.

[0003] Dual-redundant permanent magnet synchronous motors can be divided into two structures based on the winding embedding position: series structure and parallel structure. The series structure requires two sets of stators and two sets of rotors, similar to connecting two independent motors in series with the same motor shaft. This structure allows for complete isolation of thermal, magnetic field, and electrical interference between the two redundant windings, resulting in convenient control and very high reliability. However, it has low power density, a larger size, and is inconvenient for installation. The parallel structure, which is more widely used, has only one rotor. The two redundant windings are independent and embedded in the same stator core, sharing a single motor shaft. In this structure, a failure in one redundant winding will not generate excess electromagnetic torque on the other. Compared to the series structure, it has smaller torque ripple, lower losses, and no significant harmonic component influence. However, because the two windings generate magnetic fields, heat, and electrical interference, reliability may be somewhat affected.

[0004] In real-world applications, electric motors are subject to numerous external disturbances, which inevitably negatively impact the balance of the dual-redundant current. Current imbalance can lead to problems such as large torque fluctuations, uneven winding heating, increased motor noise, and reduced operating efficiency; long-term operation can even damage the insulation. To address this issue, current balancing strategies are increasingly being applied to the control of dual-redundant permanent magnet synchronous motors.

[0005] Traditional current balancing strategies divide the speed loop output into two parts, each serving as a reference for a separate q-axis current loop with dual redundancy. The difference between the current reference value and the feedback value is calculated, and closed-loop control is used to make the feedback current track the reference current, thus achieving the goal of balancing the dual-redundancy current. This method results in a slow current balancing process and poor dynamic response, making it unsuitable for systems with high speed requirements.

[0006] Therefore, how to more effectively balance the current of dual redundancy is a problem that needs to be solved. Summary of the Invention

[0007] The purpose of this application is to provide a current balancing method for a dual-redundant permanent magnet synchronous motor to solve the problem of low efficiency in balancing dual-redundant currents in the traditional current balancing strategies of the prior art.

[0008] The technical solution of this application is: a current balancing method for a dual-redundant permanent magnet synchronous motor, comprising:

[0009] Control the dual-redundant permanent magnet synchronous motor system to operate in vector control mode, and obtain the three-phase current of the dual-redundant winding of the dual-redundant permanent magnet synchronous motor system in vector control mode;

[0010] The coordinate transformation of the three-phase currents of the two redundant windings is used to obtain the q-axis current values ​​of the two redundant windings;

[0011] The difference between the two redundant q-axis current values ​​is used as the sliding surface input value to calculate the integral sliding surface function.

[0012] Calculate the derivative of the integral sliding surface function and compare it with the derivative of the sliding surface designed based on the exponential reaching rate. Select the larger value as the error compensation signal for the dual-redundancy q-axis current value and use it as the sliding surface parameter. Substitute the sliding surface parameter into the Lyapunov function to verify whether the sliding controller is stable. If it is, proceed to the next step.

[0013] The q-axis voltage compensation value is calculated using the dual-redundancy q-axis current and the integral sliding surface function.

[0014] The q-axis voltage compensation value is injected into the dual-redundant vector closed-loop control system for current balance control.

[0015] Preferably, the vector control operation mode is specifically designed as follows:

[0016] A mathematical model of a dual-redundant permanent magnet synchronous motor is established based on a two-phase rotating coordinate system, and a vector control operation mode is implemented based on the mathematical model.

[0017] The mathematical model is as follows:

[0018] ;

[0019] ;

[0020] in:

[0021] , , , The stator voltage components are in a two-phase rotating coordinate system.

[0022] , , , These are the stator current components in a two-phase rotating coordinate system.

[0023] ω s The electric angular velocity of the rotor;

[0024] R s Stator resistance;

[0025] , , , The stator flux linkage in a two-phase rotating coordinate system is represented as:

[0026] ;

[0027] ;

[0028] in:

[0029] L d1 L d2 L q1 L q2 Let be the stator inductance in the dq coordinate system.

[0030] Preferably, the specific method for coordinate transformation of the three-phase currents of the two redundant windings is as follows:

[0031] Collect dual-redundant three-phase current , , , , , The q-axis current value with redundancy is obtained after Clark and PARK transformations. , q-axis current value with double redundancy , ,as follows:

[0032] ;

[0033] ;

[0034] in: This represents the rotor angle of the motor.

[0035] Preferably, the integral sliding surface function is calculated as follows:

[0036] Define the equations for the q-axis current difference in current loops with one redundancy and two redundancy as follows:

[0037] ;

[0038] Differentiating both sides of the q-axis current difference equation, we obtain the law of change for the q-axis current difference equation as follows:

[0039] ;

[0040] The integral switching function is selected as the sliding mode surface, the dual-redundant q-axis current difference is selected as the input of the sliding mode controller, and the controller output is set to q-axis voltage compensation. The integral sliding surface is represented as:

[0041] .

[0042] Preferably, the derivative with respect to the integral sliding surface is:

[0043] ;

[0044] in:

[0045] Among them, R s L is the motor resistance value. q1 L q2 This represents the q-axis inductance value of the motor with two redundancies.

[0046] The derivative of the sliding surface designed based on the exponential reaching rate is:

[0047] ;

[0048] In the formula, sgn(s) is the sign function, defined as:

[0049] .

[0050] Preferably, the formula for verifying the stability of the sliding mode controller is:

[0051] ;

[0052] ;

[0053] When the parameters simultaneously satisfy and If the condition is met, then the sliding mode controller of the approach rate design method is considered stable.

[0054] Preferably, the formula for calculating the q-axis voltage compensation value is:

[0055] .

[0056] Preferably, the specific method for performing the current balance control is as follows:

[0057] pass uq Dynamic compensation is performed on the q-axis current loop to change the output voltage of the dual-redundant inverter and adjust the q-axis current value; at that time... The input error of the sliding mode controller will approach zero, and the q-axis current of the dual-redundant winding will remain consistent.

[0058] The current balancing method for dual-redundant permanent magnet synchronous motors proposed in this application improves upon the traditional current average distribution balancing strategy by proposing a current balancing method based on sliding mode error compensation. This method combines the advantages of strong robustness and fast dynamic response of sliding mode control, and can quickly eliminate the current difference between the two redundancies during the operation of the dual-redundant system, thereby achieving the purpose of current balance.

[0059] Furthermore, considering the actual system parameter matching problem, based on Lyapunov's theorem, a system stability criterion is given, providing a theoretical range for parameter selection to ensure stable system operation after voltage compensation and that the motor speed will not fluctuate significantly. Attached Figure Description

[0060] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0061] Figure 1 This is a block diagram illustrating the principle of the dual-redundant permanent magnet synchronous motor current equalization control method based on sliding mode error compensation in this application.

[0062] Figure 2 This is the overall control flowchart for this application. Detailed Implementation

[0063] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0064] A current balancing method for a dual-redundant permanent magnet synchronous motor, such as Figures 1-2 As shown, where Figure 1 The diagram shows the principle block diagram of the current equalization control method for a dual-redundant permanent magnet synchronous motor based on sliding mode error compensation. Figure 2 This is the overall control flowchart for this application.

[0065] Includes the following steps:

[0066] Step S100: Control the dual-redundant permanent magnet synchronous motor system to operate in vector control mode, and obtain the three-phase current of the dual-redundant windings of the dual-redundant permanent magnet synchronous motor system in vector control mode.

[0067] Preferably, the vector control operation mode is specifically designed as follows:

[0068] A mathematical model of a dual-redundant permanent magnet synchronous motor is established based on a two-phase rotating coordinate system, and a vector control operation mode is implemented based on the mathematical model.

[0069] The mathematical model is as follows:

[0070] ;

[0071] ;

[0072] in:

[0073] , , , The stator voltage components are in a two-phase rotating coordinate system.

[0074] , , , These are the stator current components in a two-phase rotating coordinate system.

[0075] ω s The electric angular velocity of the rotor;

[0076] R s Stator resistance;

[0077] , , , The stator flux linkage in a two-phase rotating coordinate system is represented as:

[0078] ;

[0079] ;

[0080] in:

[0081] L d1 L d2 L q1 L q2 Let be the stator inductance in the dq coordinate system.

[0082] Step S200: Perform coordinate transformation on the three-phase current of the two redundant windings and input it into the mathematical model to obtain the q-axis current values ​​of the two redundant windings;

[0083] Preferably, the specific method for coordinate transformation of the three-phase currents of the two redundant windings is as follows:

[0084] Collect dual-redundant three-phase current , , , , , The q-axis current value with redundancy is obtained after Clark and PARK transformations. , q-axis current value with double redundancy , ,as follows:

[0085] ;

[0086] ;

[0087] in: This represents the rotor angle of the motor.

[0088] Step S300: The difference between the two redundant q-axis current values ​​is used as the sliding surface input value to calculate the integral sliding surface function.

[0089] Preferably, the integral sliding surface function is calculated as follows:

[0090] Define the equations for the q-axis current difference in current loops with one redundancy and two redundancy as follows:

[0091] ;

[0092] Differentiating both sides of the q-axis current difference equation, we obtain the law of change for the q-axis current difference equation as follows:

[0093] ;

[0094] The integral switching function is selected as the sliding mode surface, the dual-redundant q-axis current difference is selected as the input of the sliding mode controller, and the controller output is set to q-axis voltage compensation. The integral sliding surface is represented as:

[0095] .

[0096] Step S400: Calculate the derivative of the integral sliding surface function and compare it with the derivative of the sliding surface designed based on the exponential reaching rate. Select the larger value as the error compensation signal for the dual-redundancy q-axis current value and use it as the sliding surface parameter. Substitute the sliding surface parameter into the Lyapunov function to verify whether the sliding controller is stable. If it is, proceed to the next step.

[0097] Preferably, the derivative with respect to the integral sliding surface is:

[0098] ;

[0099] in:

[0100] Among them, R s L is the motor resistance value. q1 L q2 This represents the q-axis inductance value of the motor with two redundancies.

[0101] The derivative of the sliding surface designed based on the exponential reaching rate is:

[0102] ;

[0103] In the formula, sgn(s) is the sign function, defined as:

[0104] .

[0105] The formula for verifying the stability of the sliding mode controller is:

[0106] ;

[0107] ;

[0108] When the parameters simultaneously satisfy and If the condition is met, then the sliding mode controller of the approach rate design method is considered stable.

[0109] If the requirements are not met, the synovial surface parameters should be reselected and recalculated.

[0110] Step S500: Calculate the q-axis voltage compensation value using the dual-redundancy q-axis current and the integral sliding surface function;

[0111] Preferably, the formula for calculating the q-axis voltage compensation value is:

[0112] .

[0113] In step S600, the q-axis voltage compensation value is injected into the dual-redundant vector closed-loop control system for current balance control.

[0114] Preferably, the specific method for performing current balance control is as follows:

[0115] pass u q Dynamic compensation is performed on the q-axis current loop to change the output voltage of the dual-redundant inverter and adjust the q-axis current value; at that time... The input error of the sliding mode controller will approach zero, and the q-axis current of the dual-redundant winding will remain consistent.

[0116] In summary, this application proposes a current balancing method based on sliding mode error compensation by improving the traditional current average distribution balancing strategy. This method combines the advantages of strong robustness and fast dynamic response of sliding mode control, and can quickly eliminate the current difference between the two redundancies during the operation of a dual-redundant system, thereby achieving the purpose of current balance.

[0117] Furthermore, considering the actual system parameter matching problem, based on Lyapunov's theorem, a system stability criterion is given, providing a theoretical range for parameter selection to ensure stable system operation after voltage compensation and that the motor speed will not fluctuate significantly.

[0118] Finally, it should be noted that the accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0119] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dual-redundancy permanent magnet synchronous motor current balancing method, characterized in that, The application relates to a double-redundancy permanent magnet synchronous motor current balancing method. The double-redundancy permanent magnet synchronous motor system is controlled to run in a vector control mode, and three-phase currents of two redundant windings of the double-redundancy permanent magnet synchronous motor system in the vector control mode are obtained. The three-phase currents of the two redundant windings are subjected to coordinate transformation to obtain two-redundancy q-axis current values. The difference between the two-redundancy q-axis current values is taken as a sliding mode surface input value, and an integral sliding mode surface function is calculated. The derivative of the integral sliding mode surface function is calculated, compared with the derivative of a sliding mode surface designed based on an exponential approach rate, and the larger value is selected as an error compensation signal of the two-redundancy q-axis current values and as a sliding mode surface parameter. The sliding mode surface parameter is brought into a Lyapunov function to verify whether the sliding mode controller is stable, and if yes, the next step is performed. A q-axis voltage compensation value is calculated through the two-redundancy q-axis currents and the integral sliding mode surface function.

2. The dual redundant permanent magnet synchronous machine current balancing method of claim 1, wherein, The q-axis voltage compensation value is injected into a double-redundancy vector closed-loop control system to perform current balancing control. The vector control mode is specifically designed as follows: A mathematical model of the double-redundancy permanent magnet synchronous motor is established based on a two-phase rotating coordinate system, and the vector control mode is run based on the mathematical model. ； ； The mathematical model is specifically as follows: 、 、 、 are stator voltage components in two-phase rotating coordinate system; 、 、 、 is the stator current component in the two-phase rotating coordinate system; ω s electrical angular velocity of the rotor; R s R is the resistance of the stator , , , is the stator flux linkage in the two-phase rotating coordinate system, expressed as: ； ； Wherein: L d1 , L d2 , L q1 , L q2 is the stator inductance in d-q frame. Wherein:

3. The double-redundancy permanent magnet synchronous motor current balancing method according to claim 2, characterized in that, Collecting dual-redundancy three-phase current , , , , , , through Clark transformation and PARK transformation to obtain a redundancy q-axis current value , , dual-redundancy q-axis current value , , as follows: ； ； wherein: is the motor rotor angle.

4. The dual redundant permanent magnet synchronous machine current balancing method of claim 3, wherein, The specific method for performing coordinate transformation on the three-phase currents of the two redundant windings is as follows: The calculation method of the integral sliding mode surface function is as follows: ； The q-axis current difference equation in the current loop of one redundancy and two redundancies is defined as follows: ； The integral switching function is selected as a sliding mode surface, a dual-redundancy q-axis current difference value is selected as an input of a sliding mode controller, and a controller output is set as q-axis voltage compensation The integral sliding mode surface is expressed as 。 The derivative of the q-axis current difference equation is obtained, and the variation law of the q-axis current difference equation is as follows:

5. The double-redundancy permanent magnet synchronous motor current balancing method according to claim 4, characterized in that, ； The derivative of the integral sliding mode surface is as follows: wherein R s is the motor resistance value; L q1 , L q2 is the motor two-redundancy q-axis inductance value; Wherein: ； The derivative of the sliding mode surface designed based on the exponential approach rate is as follows: 。 6. The dual redundant permanent magnet synchronous machine current balancing method of claim 5, wherein, In the formula, sgn(s) is a sign function, which is defined as follows: ； ； When the parameters satisfy and simultaneously, then the sliding mode controller of the reaching rate design method is stable.

7. The dual redundant permanent magnet synchronous machine current balancing method of claim 6, wherein, The formula for verifying whether the sliding mode controller is stable is as follows: 。 8. The dual-residue permanent magnet synchronous motor current equalization method of claim 7, wherein, The calculation formula of the q-axis voltage compensation value is as follows: The specific method for performing the current balancing control is as follows: By u q The dynamic compensation is carried out on the q-axis current loop, the output voltage of the dual-redundancy inverter is changed, and the dual-redundancy q-axis current value is adjusted; when The input error of the sliding mode controller will tend to be zero, and the q-axis currents of the dual-redundancy windings will remain consistent.

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