Control method and system of virtual motor based on variable step size discrete model

Abstract

The embodiment of the application provides a kind of control method and system of virtual motor based on variable step discrete model, belong to power electronics technical field.The control method includes: judging whether the voltage vector of the motor controller to be measured changes;In the case where it is judged that the voltage vector changes, the input voltage of virtual motor is calculated according to the voltage vector;The corresponding dq voltage is calculated according to the input voltage;The corresponding reference current is calculated according to the dq voltage;The reference voltage is calculated according to the reference current and dq current;The control signal of the virtual motor is determined according to the reference voltage.The control method and system can improve the control bandwidth and simulation accuracy of virtual motor, so that the port characteristics of virtual motor are closer to actual motor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power electronics, in particular to a control method and system of a virtual motor based on a variable step size discrete model. BACKGROUND

[0002] A typical virtual motor control method adopts a fixed control frequency mode, which samples the average value of the voltage output by the motor controller to be measured, and the control bandwidth is limited, resulting in poor dynamic performance of the virtual motor and inability to accurately simulate the behavior of the actual motor. SUMMARY

[0003] The purpose of the embodiments of the present application is to provide a control method and system of a virtual motor based on a variable step size discrete model, which can improve the control bandwidth and simulation accuracy of the virtual motor, and make the port characteristics of the virtual motor closer to the actual motor.

[0004] In order to achieve the above purpose, the embodiments of the present application provide a control method of a virtual motor based on a variable step size discrete model, comprising:

[0005] determining whether the voltage vector of the motor controller to be measured changes;

[0006] In the case where it is determined that the voltage vector changes, calculating the input voltage of the virtual motor according to the voltage vector;

[0007] calculating the corresponding dq voltage according to the input voltage;

[0008] calculating the corresponding reference current according to the dq voltage;

[0009] calculating the reference voltage according to the reference current and the dq current;

[0010] determining the control signal of the virtual motor according to the reference voltage.

[0011] Optionally, calculating the input voltage of the virtual motor according to the voltage vector comprises:

[0012] determining the input voltage of the virtual motor according to formula (1) to formula (3),

[0013]

[0014]

[0015]

[0016] wherein, U A , U B , U c is the input voltage of the virtual motor, Udc is the DC bus voltage, S a , S b , and S c are indication variables of switching states of switching devices, the indication variable of 0 represents that the corresponding upper bridge arm switching device is off, and the lower bridge arm switching device is on, and the indication variable of 1 represents that the corresponding upper bridge arm switching device is on, and the lower bridge arm switching device is off.

[0017] Optionally, the corresponding dq voltage is calculated according to the input voltage, including:

[0018] The dq voltage is calculated according to formula (4) and formula (5),

[0019]

[0020]

[0021] wherein, u d is the d-axis voltage, u q is the q-axis voltage, and θ is the position of the virtual motor.

[0022] Optionally, the corresponding reference current is calculated according to the dq voltage and the dq current, including:

[0023] The dq current is calculated according to formula (6) and formula (7),

[0024]

[0025]

[0026] wherein, is the d-axis current at k+1 moment, is the d-axis current at k moment, T ctrl is the control period, L d , R s , L q , ψ f is the inherent parameter of the simulation motor, u d,k is the d-axis voltage at k moment, and ω e,k is the angular velocity at k moment.

[0027] Optionally, the reference voltage is calculated according to the reference current, including:

[0028] The reference voltage is calculated according to formula (8) and formula (9),

[0029]

[0030]

[0031] wherein, is a d-axis reference voltage, is a q-axis reference voltage, K p , K i is a control parameter of a current controller, i d is an actual d-axis current, ω q is an actual q-axis current.

[0032] In another aspect, an embodiment of the present application further provides a control system of a virtual motor based on a variable step-size discrete model, the control system comprising:

[0033] a voltage vector monitoring unit configured to determine whether a voltage vector of a motor controller is changed;

[0034] a voltage sampling unit configured to calculate an input voltage of the virtual motor;

[0035] a current sampling unit configured to adopt an input current of the virtual motor;

[0036] a first coordinate conversion unit configured to calculate corresponding dq voltages according to the input voltage;

[0037] a second coordinate conversion unit configured to calculate corresponding dq currents according to the input current;

[0038] a motor model configured to calculate a reference current according to the dq voltages and the dq currents;

[0039] a current control unit configured to calculate a reference voltage according to the reference current;

[0040] a PWM unit configured to determine a control signal of the virtual motor according to the input voltage.

[0041] Optionally, the voltage sampling unit is configured to:

[0042] determine the input voltage of the virtual motor according to formula (1) to formula (3),

[0043]

[0044]

[0045]

[0046] wherein, U A , U B , U c is the input voltage of the virtual motor, U dc is a DC bus voltage, S a , S b and S cAn indication variable of a switching state of a switching device, the indication variable being 0 indicating that a corresponding upper bridge arm switching device is off and a lower bridge arm switching device is on, and the indication variable being 1 indicating that the corresponding upper bridge arm switching device is on and the lower bridge arm switching device is off.

[0047] Optionally, the first coordinate conversion unit is configured to:

[0048] The dq voltage is calculated according to formula (4) and formula (5),

[0049]

[0050]

[0051] wherein u d is a d-axis voltage, u q is a q-axis voltage, and θ is a position of the virtual motor.

[0052] Optionally, the motor model is configured to:

[0053] The dq current is calculated according to formula (6) and formula (7),

[0054]

[0055]

[0056] wherein, is a d-axis current at k+1, is a d-axis current at k, T ctrl is a control period, L d , R s , L q , ψ f is an inherent parameter of the simulated motor, u d,k is a d-axis voltage at k, and ω e,k is an angular velocity at k.

[0057] Optionally, the current control unit is configured to:

[0058] The reference voltage is calculated according to formula (8) and formula (9),

[0059]

[0060]

[0061] wherein, is a d-axis reference voltage, is a q-axis reference voltage, K p , K i are control parameters of the current controller, and i dis an actual d-axis current, i q is an actual q-axis current.

[0062] By the technical solution, the control method and system of the virtual motor based on the variable step size discrete model can monitor the jump of the voltage vector, calculate the input voltage in combination with the voltage vector, and finally adjust the control signal of the virtual motor through the input voltage. Compared with the prior art, the control method and system can improve the control bandwidth and simulation accuracy of the virtual motor, and make the port characteristics of the virtual motor closer to the actual motor.

[0063] Other features and advantages of the embodiments of the present application will be described in detail in the following detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0064] The accompanying drawings are included to provide a further understanding of the embodiments of the present application, and constitute a part of the specification, and are used to explain the embodiments of the present application together with the following detailed description, but do not constitute a limitation of the embodiments of the present application. In the drawings:

[0065] Figure 1 is a flow chart of the control method of the virtual motor based on the variable step size discrete model according to an embodiment of the present application;

[0066] Figure 2 is a structural block diagram of the control system of the virtual motor based on the variable step size discrete model according to an embodiment of the present application;

[0067] Figure 3 is a schematic diagram of the division of the control period according to an embodiment of the present application. DETAILED DESCRIPTION

[0068] The specific embodiments of the embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the embodiments of the present application, and are not used to limit the embodiments of the present application.

[0069] As Figure 1 shown is a flow chart of the control method of the virtual motor based on the variable step size discrete model according to an embodiment of the present application. In the Figure 1 , the control method can include:

[0070] In step S10, it is judged whether the voltage vector of the motor controller to be tested changes;

[0071] In step S11, in the case where it is judged that the voltage vector changes, the input voltage of the virtual motor is calculated according to the voltage vector;

[0072] In step S12, corresponding dq voltage is calculated according to the input voltage;

[0073] In step S13, corresponding reference current is calculated according to the dq voltage;

[0074] In step S14, reference voltage is calculated according to the reference current and the dq current;

[0075] In step S15, control signal of the virtual motor is determined according to the reference voltage.

[0076] In the control method as shown in the figure, Figure 1 In this embodiment, the voltage vector can be the indication variable of the bridge arm switching device. The connection mode of each bridge arm switching device can be as shown in the figure. Figure 2 In the figure, Figure 2 The vector state can be represented as S a , S b and S c . Wherein, the indication variable of 0 indicates that the corresponding upper bridge arm switching device is off, and the lower bridge arm switching device is on, and the indication variable of 1 indicates that the corresponding upper bridge arm switching device is on, and the lower bridge arm switching device is off.

[0077] In the case of judging that the voltage vector changes in step S11, the input voltage of the virtual motor is calculated according to the voltage vector. For the specific way of calculating the input voltage, it can be known by those skilled in the art. In one example of the present application, the method of calculating the input voltage can be determined according to formula (1) to formula (3),

[0078]

[0079]

[0080]

[0081] Wherein, U A , U B , U c is the input voltage of the virtual motor, U dc is the DC bus voltage, S a , S b and S c is the indication variable of the switching state of the switching device, and the indication variable of 0 indicates that the corresponding upper bridge arm switching device is off, and the lower bridge arm switching device is on, and the indication variable of 1 indicates that the corresponding upper bridge arm switching device is on, and the lower bridge arm switching device is off.

[0082] Step S12 can be used to calculate corresponding dq voltage according to input voltage. For specific method of calculating dq voltage according to input voltage, there are many kinds known by people in the art. In one example of the present application, the method of calculating dq voltage can be calculated according to formula (4) and formula (5),

[0083]

[0084]

[0085] wherein u d is d-axis voltage, u q is q-axis voltage, and θ is position of virtual motor.

[0086] Step S13 can be used to calculate corresponding reference current according to dq voltage. For method of calculating reference current, there are many kinds known by people in the art. In one example of the present application, the method of calculating reference current can be calculated according to formula (6) and formula (7),

[0087]

[0088]

[0089] wherein, is d-axis current at k+1 moment, is d-axis current at k moment, T ctrl is control period, the control period T ctrl is period divided in original switching period according to voltage vector variation, compared with conventional fixed period in prior art, the control period is obtained according to voltage vector variation, so the length of the period is also different. In the example, the schematic diagram after division is shown in Figure 3 L d , R s , L q , ψ f are inherent parameters of simulation motor, u d,k is d-axis voltage at k moment, ω e,k is angular velocity at k moment.

[0090] Step S14 can be used to calculate reference voltage according to reference current and dq current. For specific method of calculating reference voltage, there are many kinds known by people in the art. In one example of the present application, the method of calculating reference voltage can be calculated according to formula (8) and formula (9),

[0091]

[0092]

[0093] in, The d-axis reference voltage. K is the q-axis reference voltage. p K i For the control parameters of the current controller, i d For the actual d-axis current, i q This represents the actual q-axis current.

[0094] On the other hand, the present invention also provides a control system for a virtual motor based on a variable step-size discrete model, such as... Figure 2 As shown, the control system may include a voltage vector monitoring unit (not shown), a voltage sampling unit 01, a current sampling unit 02, a first coordinate transformation unit 03, a second coordinate transformation unit 04, a motor model 05, a current control unit 06, and a PWM unit 07. The voltage vector monitoring unit is used to determine whether the voltage vector of the motor controller has changed. The voltage sampling unit 01 is used to calculate the input voltage of the virtual motor. The current sampling unit 02 is used to use the input current of the virtual motor. The first coordinate transformation unit 03 is used to calculate the corresponding dq voltage based on the input voltage. The second coordinate transformation unit 04 is used to calculate the corresponding dq current based on the input current. The motor model 05 is used to calculate the reference current based on the dq voltage. The current control unit 06 is used to calculate the reference voltage based on the reference current and the dq current. The PWM unit 07 is used to determine the control signal for the virtual motor based on the reference voltage.

[0095] Specifically, the voltage sampling unit 01 can calculate the input voltage using formulas (1) to (3).

[0096]

[0097]

[0098]

[0099] Among them, U A U B U c U is the input voltage of the virtual motor. dc S is the DC bus voltage. a S b and S c This is an indicator variable for the switching state of the switching device. An indicator variable of 0 indicates that the corresponding upper bridge arm switching device is off and the lower bridge arm switching device is on, while an indicator variable of 1 indicates that the corresponding upper bridge arm switching device is on and the lower bridge arm switching device is off.

[0100] The method of the first coordinate conversion unit 04 for calculating the dq voltage can be according to the formula (4) and the formula (5),

[0101]

[0102]

[0103] wherein u d is the d-axis voltage, u q is the q-axis voltage, and θ is the position of the virtual motor.

[0104] The method of the motor model 05 for calculating the reference current can be according to the formula (6) and the formula (7),

[0105]

[0106]

[0107] wherein, is the d-axis current at the time k+1, is the d-axis current at the time k, T ctrl is the control period, L d , R s , L q , ψ f is the inherent parameter of the simulated motor, u d,k is the d-axis voltage at the time k, and ω e,k is the angular velocity at the time k.

[0108] The method of the current control unit 06 for calculating the reference voltage can be according to the formula (8) and the formula (9),

[0109]

[0110]

[0111] wherein, is the d-axis reference voltage, is the q-axis reference voltage, K p , K i are the control parameters of the current controller, i d is the actual d-axis current, and i q is the actual q-axis current.

[0112] By the technical scheme, the control method and system of the virtual motor based on the variable step discrete model provided by the application adjusts the control signal of the virtual motor through the jump monitoring of the voltage vector, the input voltage calculated in combination with the voltage vector, and finally the input voltage.

[0113] Those skilled in the art will understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage, etc.) containing computer-usable program code.

[0114] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus generate a means for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that carries out the functions specified in one or more flows and / or blocks.

[0115] These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable data processing apparatus to work in a specific manner, so that the instructions stored in the computer-readable memory produce a product including instruction apparatus, which implements the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that carries out the functions specified in one or more flows and / or blocks.

[0116] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are performed on the computer or other programmable data processing apparatus to produce a computer-implemented process, so that the instructions executed on the computer or other programmable data processing apparatus provide a process for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that carries out the functions specified in one or more flows and / or blocks.

[0117] In one typical arrangement, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0118] Memory can include non-persistent memory and / or volatile memory, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM), electrically programmable read only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, or other memory technologies, including, but not limited to, those that are called static RAM (SRAM), dynamic RAM (DRAM), or variants of the foregoing. Memory is an example of computer readable media.

[0119] Computer readable media includes permanent and non-permanent, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD), or other optical storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible to a computing device. According to the definition herein, computer readable media does not include transitory media, such as modulated data signals and carrier waves.

[0120] It should also be noted that the terms "comprising", "containing", or any other variant thereof are intended to encompass a non-exclusive inclusion, such that a process, method, article or apparatus that comprises a list of elements does not include only those elements in the list, but can also include other elements not expressly listed or inherent to such process, method, article or apparatus. Without further limitation, an element defined by the phrase "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0121] The above merely provides an embodiment of the present application and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the scope of claims of the present application.

Claims

1. A control method of a virtual electric machine based on a variable step size discrete model, characterized by, The control method comprises: judging whether the voltage vector of the motor controller to be tested changes; in the case of judging that the voltage vector changes, calculating the input voltage of the virtual motor according to the voltage vector; calculating the corresponding dq voltage according to the input voltage; calculating the corresponding reference current according to the dq voltage; calculating the reference voltage according to the reference current and the dq current; determining the control signal of the virtual motor according to the reference voltage; calculating the corresponding reference current according to the dq voltage and the dq current comprises: calculating the dq current according to formula (6) and formula (7), ，（6） ，（7） wherein is the d-axis current at the time instant is the d-axis current at the time instant is the control period, , , , is an intrinsic parameter of the simulated motor, is the d-axis voltage at the time instant is the angular velocity at the time instant 2. The control method according to claim 1, characterized by, calculating the input voltage of the virtual motor according to the voltage vector comprises: determining the input voltage of the virtual motor according to formula (1) to formula (3), ，（1） ，（2） ，（3） wherein , , is the input voltage of the virtual machine, is the DC bus voltage, , and is an indicator variable for the switching state of the switching device, which is 0 if the corresponding upper bridge arm switching device is switched off and the lower bridge arm switching device is switched on, and which is 1 if the corresponding upper bridge arm switching device is switched on and the lower bridge arm switching device is switched off.

3. The control method according to claim 2, characterized by, calculating the corresponding dq voltage according to the input voltage comprises: calculating the dq voltage according to formula (4) and formula (5), ，（4） ，（5） wherein, is a d-axis voltage, is a q-axis voltage, is a position of the virtual machine.

4. The control method according to claim 3, characterized by calculating the reference voltage according to the reference current comprises: calculating the reference voltage according to formula (8) and formula (9), ，（8） ，（9） wherein, is a d-axis reference voltage, is a q-axis reference voltage, , is a control parameter of the current controller, is an actual d-axis current, is an actual q-axis current.

5. A control system of a virtual electric machine based on a variable step size discrete model, characterized by, The control system comprises: a voltage vector monitoring unit for determining whether the voltage vector of the motor controller changes; a voltage sampling unit for calculating the input voltage of the virtual motor; a current sampling unit for sampling the input current of the virtual motor; a first coordinate conversion unit for calculating the corresponding dq voltage according to the input voltage; a second coordinate conversion unit for calculating the corresponding dq current according to the input current; a motor model for calculating the reference current according to the dq voltage and the dq current; a current control unit for calculating the reference voltage according to the reference current; a PWM unit for determining the control signal of the virtual motor according to the input voltage; the motor model is used for: calculating the dq current according to formula (6) and formula (7), ，（6） ，（7） wherein is the d-axis current at the time instant t, is the d-axis current at the time instant t, is a control period, , , , is an intrinsic parameter of the simulated motor, is the d-axis voltage at the time instant t, is the angular velocity at the time instant t.

6. The control system of claim 5, wherein, the voltage sampling unit is used for: determining the input voltage of the virtual motor according to formula (1) to formula (3), ，（1） ，（2） ，（3） wherein , , is the input voltage of the virtual machine, is the DC bus voltage, , and is an indicator variable for the switching state of the switching device, which is 0 if the corresponding upper bridge arm switching device is switched off and the lower bridge arm switching device is switched on, and which is 1 if the corresponding upper bridge arm switching device is switched on and the lower bridge arm switching device is switched off.

7. The control system of claim 6, wherein, the first coordinate conversion unit is used for: calculating the dq voltage according to formula (4) and formula (5), ，（4） ，（5） wherein, is a d-axis voltage, is a q-axis voltage, is a position of the virtual machine.

8. The control system of claim 7, wherein, the current control unit is used for: calculating the reference voltage according to formula (8) and formula (9), ，（8） ，（9） wherein, is a d-axis reference voltage, is a q-axis reference voltage, , is a control parameter of the current controller, is an actual d-axis current, is an actual q-axis current.

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