Control Method of Dual-Winding Motor with Torque Balance

Abstract

The present invention relates to a control method for a dual-winding motor with torque balance, comprising the following steps: Step 1, two sets of controllers are adopted, each operating in a speed control mode and calculating the estimated torque respectively, and a torque balance algorithm is included in both controllers; Step 2, the two controllers exchange the estimated torque data calculated by each; Step 3, the estimated torque data, the speed command data and the motor speed signal are subjected to the operation of the torque balance algorithm to dynamically adjust the output torque of each of the two sets of controllers, ultimately making the output torques of the two sets of controllers equal, and then driving the dual windings to operate simultaneously through the output torque; Step 4, when any one of the controllers detects a fault, the torque balance algorithm stops operating, and the other set of controllers controls the single winding to operate. There is no master-slave distinction between the two sets of controllers of the present invention, and the safety is high; at the same time, by adding the torque balance algorithm to both sets of controllers, the two sets of controllers and the motor winding loads are the same, and the system has a relatively long service life.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and more specifically, to a control method for a dual-winding motor with torque balance. Background Art

[0002] With the continuous progress of technology, new energy pure electric buses are also developing rapidly, which greatly improves the requirements for their appearance, volume, and performance. Most current new energy buses use an air pump or an oil pump controller to control an air pump or a steering pump integrated with a motor. Such a separate control method occupies more space volume and using two motors also increases costs. To optimize the space layout and save resource costs, using a dual-winding motor to control air supply and steering simultaneously is of great significance for sustainable development. However, there are still many problems in the control of dual-winding motors at present. For example, the controller causes uneven torque distribution in the dual windings, resulting in low system efficiency. Another example is that the algorithms of some dual-winding motor controllers are complex, with high performance requirements and high costs.

[0003] Chinese patent publication CN2019112204144 discloses a dual-winding permanent magnet synchronous motor system, including a dual-winding permanent magnet synchronous motor and two sets of independent control systems. The resolver decoding circuits of the two sets of control systems share a resolver, and the resolver decoding circuit of each control system obtains the position and speed information of the motor rotor from the resolver to independently control a corresponding set of windings.

[0004] Although two controllers are used to independently control the windings in this patent, when the above solution works in the speed loop, there will be a problem of uneven torque distribution. It is possible that one winding and its controller operate under a large load for a long time, while the other winding operates without load, reducing the life of the whole system. In extreme cases, it is possible that one winding is in positive torque electric operation and the other winding is in negative torque power generation, causing serious problems such as low system efficiency and power waste. Summary of the Invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a control method for a dual-winding motor with torque balance, which has high safety, low cost and can make the two windings have the same load, improving the life of the system.

[0006] To achieve the above invention purpose, the present invention adopts the following technical solutions:

[0007] A control method for a dual-winding motor with torque balance, comprising the following steps:

[0008] Step 1, adopt two sets of controllers, each operating in a speed control mode, each calculating and estimating torque, and a torque balance algorithm is provided in both controllers;

[0009] Step 2: Exchange the estimated torque data calculated by each of the two controllers through the communication interface between the two controllers;

[0010] Step 3: Perform an operation of the torque balance algorithm on the estimated torque data, the speed command data, and the motor speed signal, dynamically adjust the output torque of each of the two sets of controllers, and finally make the output torques of the two sets of controllers equal, and then drive the dual windings to operate simultaneously through the output torque;

[0011] Step 4: When any one of the controllers detects a fault, the torque balance algorithm stops running, and the single winding operation is controlled by the other set of controllers.

[0012] As a preferred solution: The calculation process of the estimated torque in Step 1 is as follows:

[0013] According to the established system mathematical model, the three-phase current signals of the two windings are transformed by Clarke transformation and Park transformation to obtain the d-axis components Id1 and Id2 and the q-axis components Iq1 and Iq2 of the current in the rotating coordinate system;

[0014] According to the formula TqAct = p(Psid*Iq - Psiq*Id), calculate the current estimated torque TqAct, where Psid is the d-axis component of the motor magnetic flux, Psiq is the q-axis component of the magnetic flux, and p is the number of pole pairs of the motor.

[0015] As a preferred solution: The Clarke transformation formula is

[0016]

[0017] The Park transformation formula is

[0018]

[0019] As a preferred solution: The operation process of the torque balance algorithm in Step 3 is as follows:

[0020] After Controller 1 receives the estimated torque TqAct2 of Controller 2, it performs a subtraction calculation with its own estimated torque TqAct1 to obtain the difference Tq_Delta between the two;

[0021] Limit the amplitude of Tq_Delta. If Tq_Delta is less than the limit value Tq_Delta_Limit, send Tq_Delta to the speed PI controller; if Tq_Delta is greater than the limit value Tq_Delta_Limit, then send Tq_Delta_Limit to the speed PI controller;

[0022] The controller 1 collects the motor speed signal, calculates the difference from the speed command to obtain the speed difference Spd_Delta. The proportion term is obtained by multiplying Spd_Delta by the proportional coefficient P. The integral term of this time is obtained by multiplying Spd_Delta by the integral coefficient I and accumulating Tq_Delta and the previous integral term. The sum of the integral term and the proportion term gives the output torque TqReq of the controller 1. The reference formula is: TqReq = Spd_Delta * P + ∑(Spd_Delta * I + Tq_Delta);

[0023] After receiving the estimated torque TqAct1 of the controller 1, the controller 2 performs the same calculation process as the controller 1 to obtain the output torque TqReq of the controller 2.

[0024] As a preferred solution: The process of dynamically adjusting the output torques of the two sets of controllers in step 3 includes collecting the three-phase current signals of the two windings of the motor multiple times and calculating the estimated torque, simultaneously collecting the motor speed signal multiple times, and performing the torque balance algorithm operation on the above data multiple times, finally making the output torque TqReq of the controller 1 the same as the output torque TqReq of the controller 2.

[0025] As a preferred solution: The process of driving the dual-winding operation with the output torque is as follows: The output torque TqReq is calculated through MTPA to obtain the current commands Id* and Iq*. After the difference between the current commands and the collected currents Id and Iq is sent to the current loop controller, the voltage command is obtained. The voltage command is modulated by SVPWM to generate the mosfet drive signal and finally drives the motor to rotate.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] The dual-winding motor of the present invention adopts two sets of controllers, and there is no master-slave relationship between the two sets of controllers. They operate independently, with high safety. At the same time, by adding the torque balance algorithm to both sets of controllers, the loads of the two sets of controllers and the motor windings are the same, and the system has a relatively long lifespan. It can also avoid the low-efficiency operation condition where one winding is in the electric state and the other winding is in the generating state. In addition, the added torque balance algorithm is simple, has low requirements for the operation performance of the main chip, and has a low cost. Although there is still a communication connection between the two sets of controllers, the communication rate requirement between the controllers is low, and the communication anti-interference ability is strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The specification drawings forming a part of this application are used to provide a further understanding of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not constitute a limitation to this application.

[0029] Figure 1Schematic diagram of the principle of the control method of the present invention;

[0030] Figure 2 Schematic diagram of the principle of the torque balance algorithm of the present invention. Detailed implementation manners

[0031] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0032] It should be noted that the terms used herein are only for describing the specific implementation manners and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of the features, steps, operations, devices, components, and / or combinations thereof.

[0033] In addition, in the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation of the present invention.

[0034] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "plural" is two or more, unless otherwise clearly defined.

[0035] In the present invention, unless otherwise clearly specified and defined, the terms "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0036] In the present invention, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "beneath" and "underneath" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicating that the horizontal height of the first feature is less than that of the second feature.

[0037] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0038] As Figure 1 and Figure 2 shown, a control method for a dual-winding motor with torque balance includes the following steps:

[0039] Step 1: Two sets of controllers are adopted, each operating in the speed control mode, each calculating the estimated torque, and a torque balance algorithm is provided in both controllers. The calculation process of the estimated torque is as follows:

[0040] According to the established system mathematical model, the three-phase current signals of the two sets of windings are transformed through Clark transformation and Park transformation to obtain the d-axis components Id1 and Id2 and the q-axis components Iq1 and Iq2 of the current in the rotating coordinate system;

[0041] The Clarke transformation formula is

[0042]

[0043] The Park transformation formula is

[0044]

[0045] Then, according to the formula TqAct = p(Psid * Iq - Psiq * Id), the current estimated torque TqAct is calculated, where Psid is the d-axis component of the motor magnetic flux, Psiq is the q-axis component of the magnetic flux, and p is the number of pole pairs of the motor.

[0046] Step 2: Exchange the calculated estimated torque data through the communication interface (such as an SPI interface, etc.) between the two controllers;

[0047] Step 3: Perform the operation of the torque balance algorithm on the estimated torque data, the speed command data, and the motor speed signal, dynamically adjust the output torques of the two sets of controllers respectively, and finally make the output torques of the two sets of controllers equal, and then drive the dual windings to operate simultaneously through the output torque;

[0048] The operation process of the torque balance algorithm is as follows:

[0049] After receiving the estimated torque TqAct2 of controller 2, controller 1 calculates the difference with its own estimated torque TqAct1 to obtain the difference value Tq_Delta between the two;

[0050] Perform amplitude limit on Tq_Delta. If Tq_Delta is less than the limit value Tq_Delta_Limit, send Tq_Delta to the speed PI controller; if Tq_Delta is greater than the limit value Tq_Delta_Limit, then send Tq_Delta_Limit to the speed PI controller;

[0051] Controller 1 collects the motor speed signal, calculates the difference with the speed command to obtain the speed difference Spd_Delta. Multiply Spd_Delta by the proportional coefficient P to obtain the proportional term. Multiply Spd_Delta by the integral coefficient I and accumulate Tq_Delta and the previous integral term to obtain the current integral term. Sum the integral term and the proportional term to obtain the output torque TqReq of controller 1. The reference formula is: TqReq = Spd_Delta * P + ∑(Spd_Delta * I + Tq_Delta);

[0052] After receiving the estimated torque TqAct1 of controller 1, controller 2 performs the same calculation process as controller 1 to obtain the output torque TqReq of controller 2.

[0053] Since the amplitude of Tq_Delta is limited in this embodiment, the output torques obtained after the first torque balance algorithm are not necessarily the same. It is necessary to repeatedly collect the three-phase current signals of the two windings of the motor and calculate the estimated torque, and at the same time collect the motor speed signal multiple times, and perform the torque balance algorithm operation on the above data multiple times. Finally, the output torque TqReq of controller 1 can be made the same as the output torque TqReq of controller 2.

[0054] The process of driving the dual winding operation by the output torque in step 3 is as follows: The output torque TqReq is calculated through MTPA to obtain the current commands Id* and Iq*. After the difference between the current commands and the collected currents Id and Iq is sent to the current loop controller to obtain the voltage command, the voltage command is modulated by SVPWM to generate the mosfet drive signal, and finally drives the motor to rotate.

[0055] Step 4, when any one of the controllers detects a fault, the torque balance algorithm stops running, and the other set of controllers controls the single winding operation without state and mode switching.

[0056] The two sets of controller algorithms of the present invention operate independently in the speed control mode. There is no master-slave relationship between the two sets of controllers, and they operate independently respectively, with high security. Torque balance algorithms are added to both Controller 1 and Controller 2 to achieve power balance, so that the two sets of controllers and the motor windings have the same load, and the system has a relatively long lifespan. It avoids the inefficient operation situation where one winding is in the electric state while the other is in the generating state. At the same time, the torque balance algorithm of the present invention is relatively simple, has low requirements for the computing performance of the main chip, and has a relatively low cost. In addition, although there is still communication between the two sets of controllers, the communication rate requirement between the controllers is low, the communication anti-interference ability is strong, and the overall stability of the system is relatively high.

[0057] In the description of this specification, the description with reference to terms such as "an embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0058] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principles and purposes of the present invention. Any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. Control method of a dual-winding motor with torque balance, characterized in that, It includes the following steps: Step 1: Adopt two sets of controllers, each operating in speed control mode, each calculating the estimated torque, and a torque balance algorithm is provided in both controllers; Step 2: Exchange the calculated estimated torque data through the communication interface between the two controllers; Step 3: Perform the operation of the torque balance algorithm on the estimated torque data, speed command data, and motor speed signal, dynamically adjust the output torque of each of the two sets of controllers, and finally make the output torques of the two sets of controllers equal, and then drive the dual windings to operate simultaneously through the output torque; Step 4: When any one of the controllers detects a fault, the torque balance algorithm stops running, and the single winding operation is controlled by the other set of controllers; The operation process of the torque balance algorithm in Step 3 is as follows: After Controller 1 receives the estimated torque TqAct2 of Controller 2, it calculates the difference with its own estimated torque TqAct1 to obtain the difference value Tq_Delta between the two; Perform amplitude limiting on Tq_Delta. If Tq_Delta is less than the limit value Tq_Delta_Limit, send Tq_Delta to the speed PI controller; if Tq_Delta is greater than the limit value Tq_Delta_Limit, then send Tq_Delta_Limit to the speed PI controller; Controller 1 collects the motor speed signal, calculates the difference with the speed command to obtain the speed difference Spd_Delta. Multiply Spd_Delta by the proportional coefficient P to obtain the proportional term. Multiply Spd_Delta by the integral coefficient I and accumulate Tq_Delta and the previous integral term to obtain the current integral term. Sum the integral term and the proportional term to obtain the output torque TqReq of Controller 1. The reference formula is: TqReq = Spd_Delta * P + ∑(Spd_Delta * I + Tq_Delta); After Controller 2 receives the estimated torque TqAct1 of Controller 1, it performs the same calculation process as Controller 1 to obtain the output torque TqReq of Controller 2.

2. The control method of the dual-winding motor with torque balance according to claim 1, wherein: The calculation process of the estimated torque in Step 1 is as follows: According to the established system mathematical model, the three-phase current signals of the two windings are transformed through Clark transformation and Park transformation to obtain the d-axis component Id1 and Id2 and q-axis component Iq1 and Iq2 of the current in the rotating coordinate system; According to the formula TqAct = p(Psid * Iq - Psiq * Id), calculate the current estimated torque TqAct, where Psid is the d-axis component of the motor flux linkage, Psiq is the q-axis component of the flux linkage, and p is the number of pole pairs of the motor.

3. The control method of the dual-winding motor with torque balance according to claim 2, characterized in that: The Clarke transformation formula is The Park transformation formula is 4. The control method of the dual-winding motor with torque balance according to claim 1, characterized in that: The process of dynamically adjusting the output torque of each of the two sets of controllers in Step 3 includes collecting the three-phase current signals of the two windings of the motor multiple times and calculating the estimated torque, simultaneously collecting the motor speed signal multiple times, and performing the torque balance algorithm operation on the above data multiple times, and finally making the output torque TqReq of Controller 1 the same as the output torque TqReq of Controller 2.

5. The control method of the dual-winding motor with torque balance according to claim 1, characterized in that: The process of driving the dual-winding operation by the output torque in Step 3 is as follows: The output torque TqReq is calculated through MTPA to obtain the current commands Id* and Iq*. After the difference between the current commands and the collected currents Id and Iq is calculated, it is sent to the current-loop controller to obtain the voltage command. The voltage command is modulated by SVPWM to generate the mosfet drive signal, and finally drives the motor to rotate.

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