Motor control method with LC filter, frequency converter and motor control system

Abstract

The invention relates to the technical field of motor control with LC filters, and discloses a motor control method with an LC filter, a frequency converter and a motor control system.The method comprises the steps that input motor parameter information is obtained, the motor parameter information comprises three-phase acquisition current at the input side of the LC filter and motor reconstruction parameters at the last moment; determining a shaft control voltage according to the motor reconstruction parameter and a given control instruction input at the current moment, and determining a shaft control current according to the three-phase acquisition current and the motor reconstruction parameter; and determining a motor control instruction according to the shaft control voltage, the shaft control current and preset motor device parameters, and controlling the motor based on the motor control instruction. According to the invention, the control cost of the motor with the LC filter is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control with an LC filter, and particularly to a motor control method, an inverter, and a motor control system with an LC filter. Background Art

[0002] With the rapid development of motors, motors with LC filters are used more and more frequently in various fields, which also puts forward higher requirements for the control of motors with LC filters by users.

[0003] The traditional motor control method with an LC filter is to collect motor parameters through the use of acquisition devices with different parameters, such as a rotor position sensor, and then implement motor control based on the collected motor parameters. This motor control method with an LC filter has great defects, and there will be a phenomenon of needing to use acquisition devices with different parameters. That is, this motor control method with an LC filter will cause a relatively high cost for the control of motors with LC filters due to the need to use acquisition devices with different parameters. Summary of the Invention

[0004] The main purpose of the present invention is to propose a motor control method, an inverter, and a motor control system with an LC filter, aiming to solve the technical problem of how to reduce the control cost of motors with LC filters.

[0005] To achieve the above object, the present invention provides a motor control method with an LC filter. The motor control method with an LC filter includes the following steps:

[0006] Obtain the input motor parameter information, where the motor parameter information includes the three-phase collected current on the input side of the LC filter and the motor reconstruction parameters at the previous moment;

[0007] Determine the shaft control voltage according to the motor reconstruction parameters and the given control instruction input at the current moment, and determine the shaft control current according to the three-phase collected current and the motor reconstruction parameters;

[0008] Determine the motor control instruction according to the shaft control voltage, the shaft control current, and the preset electrical device parameters, so as to control the motor based on the motor control instruction.

[0009] Optionally, the motor reconstruction parameters include the first estimated motor rotor speed, the first reconstructed motor d-axis current, and the first reconstructed motor q-axis current. The given control instruction includes the given motor rotor speed and the given motor d-axis current. The shaft control voltage includes the d-axis control voltage and the q-axis control voltage. The step of determining the shaft control voltage according to the motor reconstruction parameters and the given control instruction input at the current moment includes:

[0010] Perform speed loop control based on the first estimated motor rotor speed and the given motor rotor speed to generate the q-axis current;

[0011] Perform current loop control based on the first reconstructed motor d-axis current and the given motor d-axis current to generate the d-axis control voltage;

[0012] Perform current loop control based on the first reconstructed motor q-axis current and the q-axis current to generate the q-axis control voltage.

[0013] Optionally, the motor reconstruction parameters include the first estimated motor position, and the step of determining the axis control current according to the three-phase sampled current and the motor reconstruction parameters includes:

[0014] Perform a first current transformation on the three-phase sampled current to obtain a first control current, and perform a second current transformation on the first control current and the first estimated motor position to obtain the axis control current, where the first current transformation includes the Clarke transformation and the second current transformation includes the Park transformation.

[0015] Optionally, the step of determining the motor control command according to the axis control voltage, the axis control current, and the preset electrical machine device parameters includes:

[0016] Determine the reconstructed control current according to the axis control current and the preset electrical machine device parameters, and determine the reconstructed control voltage according to the axis control voltage and the preset electrical machine device parameters;

[0017] Construct a position observer in the axis coordinate based on the electrical machine device parameters, and input the axis control voltage and the reconstructed control current into the position observer to obtain the estimated parameters of the motor at the current moment;

[0018] Determine the motor control command according to the estimated parameters of the motor and the reconstructed control voltage.

[0019] Optionally, the reconstructed control voltage includes the q-axis reconstructed control voltage and the d-axis reconstructed control voltage, and the step of determining the reconstructed control voltage according to the axis control voltage and the preset electrical machine device parameters includes:

[0020] Determine the d-axis control voltage in the axis control voltage, and input the d-axis control voltage and the preset electrical machine device parameters into the d-axis voltage reconstruction formula to obtain the d-axis reconstructed control voltage;

[0021] Determine the q-axis control voltage in the axis control voltage, and input the q-axis control voltage and the preset electrical machine device parameters into the q-axis voltage reconstruction formula to obtain the q-axis reconstructed control voltage.

[0022] Optionally, the motor estimated parameters include the second estimated motor rotor speed, and the step of determining the motor control command according to the motor estimated parameters and the reconstructed control voltage includes:

[0023] Determine the q-axis reconstructed control voltage and the d-axis reconstructed control voltage in the reconstructed control voltage, and perform a third transformation based on the q-axis reconstructed control voltage, the d-axis reconstructed control voltage, and the second estimated motor rotor speed to obtain a transformed control voltage, where the third transformation includes an inverse Park transformation;

[0024] Adjust the transformed control voltage based on a preset waveform modulation to obtain a motor control command.

[0025] Optionally, the shaft control current includes a d-axis control current and a q-axis control current, the reconstructed control current includes a d-axis reconstructed control current and a q-axis reconstructed control current, and the step of determining the reconstructed control current according to the shaft control current and preset electrical machine device parameters includes:

[0026] Determine the d-axis control current in the shaft control current, and input the d-axis control current and the preset electrical machine device parameters into a d-axis current reconstruction formula to obtain the d-axis reconstructed control current;

[0027] Determine the q-axis control current in the shaft control current, and input the q-axis control current and the preset electrical machine device parameters into a q-axis current reconstruction formula to obtain the q-axis reconstructed control current.

[0028] Optionally, after the step of inputting the shaft control voltage and the reconstructed control current into the position observer to obtain the motor estimated parameters at the current moment, it includes:

[0029] Take the reconstructed control current and the motor estimated parameters as the current motor reconstructed parameters at the current moment, and execute the step of obtaining the input motor parameter information at the next moment, and update the current motor reconstructed parameters to the motor reconstructed parameters at the previous moment.

[0030] This application also provides an inverter, and the inverter includes:

[0031] An LC filter and an inverter, the output end of the LC filter is connected to the motor, and the input end of the LC filter is connected to the output end of the inverter;

[0032] A controller, the controller is connected to the input end of the inverter;

[0033] The controller is used to execute the steps of the motor control method with an LC filter as described above.

[0034] The present application also provides a motor control system, which includes:

[0035] A motor;

[0036] An inverter, the output end of the LC filter in the inverter is connected to the motor, and the input end of the controller in the inverter is connected to the power grid;

[0037] The inverter is also used to execute the steps of the motor control method with an LC filter as described above.

[0038] The present invention provides a motor control method with an LC filter. By obtaining the input motor parameter information, where the motor parameter information includes the three-phase sampled current on the input side of the LC filter and the motor reconstruction parameters at the previous moment; determining the shaft control voltage according to the motor reconstruction parameters and the given control instruction input at the current moment, and determining the shaft control current according to the three-phase sampled current and the motor reconstruction parameters; determining the motor control instruction according to the shaft control voltage, the shaft control current and the preset electrical device parameters, so as to control the motor based on the motor control instruction.

[0039] By obtaining the motor reconstruction parameters in the input motor parameter information and the given control instruction input at the current moment to determine the shaft control voltage, and determining the shaft control current based on the three-phase sampled current and the motor reconstruction parameters in the motor parameter information, and finally determining the motor control instruction based on the shaft control voltage, the shaft control current and the preset electrical device parameters, and then performing motor control. Thus, it avoids the phenomenon in the prior art that different parameter acquisition devices need to be used for parameter acquisition before control can be performed. By determining the shaft control voltage and the shaft control current through the motor parameter information and the given control instruction input at the current moment, and then determining the motor control instruction based on the shaft control voltage, the shaft control current and the preset electrical device parameters, that is, only the three-phase sampled current on the input side of the LC filter needs to be acquired to realize motor control, thereby reducing the use of acquisition devices such as rotor position sensors to reduce the motor control cost with an LC filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the structures shown in these drawings without creative efforts.

[0041] Figure 1 It is a schematic structural diagram of a motor control device with an LC filter for the hardware operating environment involved in the embodiment solution of the present invention;

[0042] Figure 2 This is a schematic flow diagram of the motor control method with an LC filter according to the present invention;

[0043] Figure 3 This is a schematic flow control diagram of the motor control method with an LC filter according to the present invention;

[0044] Figure 4 This is a schematic circuit diagram of the LC filter in the motor control method with an LC filter according to the present invention;

[0045] Figure 5 This is a schematic control diagram of the observer and voltage-current reconstructor in the motor control method with an LC filter according to the present invention;

[0046] Figure 6 This is a schematic control diagram of the position observer based on the dq coordinate system in the motor control method with an LC filter according to the present invention;

[0047] Figure 7 This is a schematic module diagram of the motor control system according to the present invention;

[0048] Figure 8 This is a schematic diagram of the frequency converter module according to the present invention.

[0049] The realization of the purpose, functional features and advantages of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed Embodiments

[0050] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0051] It should be noted that if there are directional indications (such as up, down, left, right, front, back,...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0052] In addition, if the descriptions such as "first" and "second" are involved in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between the various embodiments may be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0053] Refer to Figure 1 , Figure 1 FIG. is a schematic structural diagram of a motor control device with an LC filter for the hardware operating environment involved in the solution of the embodiment of the present invention.

[0054] As Figure 1 shown, the motor control device with an LC filter may include: a processor 0003, such as a central processing unit (CPU), a communication bus 0001, an acquisition interface 0002, a processing interface 0004, and a memory 0005. Among them, the communication bus 0001 is used to implement connection communication between these components. The acquisition interface 0002 may include an information collection device, an acquisition unit such as a computer. Optionally, the acquisition interface 0002 may further include a standard wired interface and a wireless interface. The processing interface 0004 may optionally include a standard wired interface and a wireless interface. The memory 0005 may be a high-speed random access memory (RAM) or a stable non-volatile memory (NVM), such as a disk memory. Optionally, the memory 0005 may also be a storage device independent of the aforementioned processor 0003.

[0055] Those skilled in the art can understand that Figure 1 the structure shown in

[0056] does not constitute a limitation on the motor control device with an LC filter, and may include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements. Figure 1 As

[0057] In Figure 1In the motor control device with an LC filter shown, the communication bus 0001 is mainly used to achieve connection and communication between components; the acquisition interface 0002 is mainly used to connect to the background server and conduct data communication with the background server; the processing interface 0004 is mainly used to connect to the deployment end (user end) and conduct data communication with the deployment end; the processor 0003 and the memory 0005 in the motor control device with an LC filter of the present invention can be arranged in the motor control device with an LC filter. The motor control device with an LC filter calls the motor control program with an LC filter stored in the memory 0005 through the processor 0003 and executes the motor control method with an LC filter provided in the embodiment of the present invention.

[0058] Based on the above hardware structure, an embodiment of the motor control method with an LC filter of the present invention is proposed.

[0059] In an embodiment of the present invention, as Figure 2 shown, Figure 2 is a schematic flowchart of the motor control method with an LC filter of the present invention. The motor control method with an LC filter includes:

[0060] Step S10, acquire the input motor parameter information, where the motor parameter information includes the three-phase collected current on the input side of the LC filter and the motor reconstruction parameters at the previous moment;

[0061] Exemplarily, with the development of motors, motors are used more and more in various fields. Due to the limitations of the performance of inverters, the traditional method of directly connecting a motor (which can be a conventional motor or a high-speed permanent magnet synchronous motor, and in this embodiment, a high-speed permanent magnet synchronous motor is taken as an example for illustration) to an inverter is likely to generate large harmonics when applied to high-speed motors, causing the current in the motor winding to distort, and further leading to the deterioration of noise, core loss, and torque ripple. Therefore, generally, an LC filter needs to be connected in series between the high-speed permanent magnet synchronous motor and the inverter to reduce current harmonics, thereby reducing motor heating and extending the service life of the motor. However, the introduction of the LC filter will cause the structure of the motor control system to change, resulting in a reduction in the control performance of the high-speed permanent magnet synchronous motor, which is specifically manifested in two aspects: 1. The loop control of the high-speed permanent magnet synchronous motor is designed based on a pure motor model (i.e., the motor model before the traditional LC filter is introduced), without considering the phase shift and parameter deviation brought by the LC filter. Therefore, the traditional current-current double-loop control cannot directly and effectively control the motor current; 2. In order to remove the position or speed sensor to further improve the reliability of the system and reduce costs, it is often necessary to use physical parameters such as back electromotive force or magnetic flux to observe the speed and position of the high-speed permanent magnet synchronous motor to achieve sensorless control of the high-speed permanent magnet synchronous motor. However, this technology highly depends on the model of the observed object. Currently, the mature methods are all established for the pure high-speed permanent magnet synchronous motor model. After adding the LC filter, the system model changes, and the accuracy and stability of the observation will further deteriorate. Based on the above problems, the most direct method is to measure more parameters to improve the control performance, such as sensors for detecting the motor terminal voltage and current or other acquisition devices. However, this type of method requires adding additional sampling devices, increasing the system cost. At the same time, it is not applicable to existing systems that do not have the corresponding functions, and the generality is low. That is, motors with fixed hardware or unable to add hardware are not suitable for using such methods. Therefore, based on the above problems, the motor control method with an LC filter of this application is proposed, thereby reducing the control cost of the motor with an LC filter.

[0062] In this embodiment, when controlling a high-speed permanent magnet synchronous motor with an LC filter, it is first necessary to obtain the input motor parameter information. Among them, the motor parameter information includes the three-phase collected current on the input side of the LC filter and the motor reconstruction parameters at the previous moment. The three-phase collected current refers to the current values of the three phases on the input side of the LC filter collected by an instrument, which can be directly collected using a current sensor or other instruments, and this is not limited here. The motor reconstruction parameters at the previous moment refer to the current, voltage, and speed values at the previous moment, and the above values are determined by calculation based on the collected parameters, rather than obtained by collecting through various instruments. It should be noted that the motor reconstruction parameters at the previous moment can be determined by calculating the parameters collected at the previous moment, or can be a custom situation, that is, the motor reconstruction parameters at the initial previous moment when the high-speed permanent magnet synchronous motor starts can be customized by the user, and then the subsequent control process can be carried out.

[0063] Step S20: Determine the shaft control voltage according to the motor reconstruction parameters and the given control instruction input at the current moment, and determine the shaft control current according to the three-phase collected current and the motor reconstruction parameters;

[0064] In this embodiment, after determining the three-phase collected current on the input side of the LC filter and the motor reconstruction parameters at the previous moment, parameter calculations will be performed on both of them respectively to determine the shaft control voltage and the shaft control current. That is, according to the motor reconstruction parameters and the given control instruction input at the current moment, and at the same time according to the three-phase collected current and the motor reconstruction parameters to determine the shaft control current. Among them, the given control instruction input at the current moment refers to the control instruction of the current and speed input at the current moment. The shaft control voltage refers to the control voltage of the dq axis, and the shaft control current refers to the control current of the dq axis. The shaft control current can be the control current of the dq axis of the inverter, and then subsequent control can be carried out based on the shaft control voltage and the shaft control current. At the same time, the entire scheme only involves the collection of three-phase currents. Therefore, compared with the method of collecting motor parameters of a high-speed permanent magnet synchronous motor using a rotor position sensor and other collection instruments and then performing motor control, the control method of this embodiment does not require the use of redundant collection devices to collect motor parameters, thereby reducing the motor control cost of the motor with an LC filter.

[0065] Step S30: Determine the motor control instruction according to the shaft control voltage, the shaft control current, and the preset electrical machine device parameters, so as to control the motor based on the motor control instruction.

[0066] In this embodiment, after determining the shaft control voltage and shaft control current, a motor control command is determined based on the shaft control voltage, the shaft control current, and preset electrical machine device parameters. That is, through formula calculation and signal transformation using the above three parameters, a motor control command for controlling the motor is obtained. Among them, the preset electrical machine device parameters at least include the relevant parameters of the LC filter and the relevant parameters of the high-speed permanent magnet synchronous motor. The motor control command refers to the command for controlling the high-speed permanent magnet synchronous motor, which mainly includes the control signal after waveform modulation of the voltage value. Then, based on the above control method, the motor control command is determined to control the motor based on the motor control command.

[0067] It is worth noting that the motor control with an LC filter in this embodiment can accurately estimate the motor rotor speed and position, and solve the voltage offset between the inverter and the motor caused by the filter without the need for a position sensor and an additional voltage and current sensor, realizing high-performance sensorless control, thereby reducing the cost of motor control with an LC filter. Moreover, voltage and current reconstruction is achieved according to the LC filter parameters and motor parameters, and then used for motor control and position observation, without relying on specific observers and hardware, having high generality and being easy to transplant into existing motor control systems.

[0068] This embodiment provides a motor control method with an LC filter. By obtaining the input motor parameter information, where the motor parameter information includes the three-phase collected current on the input side of the LC filter and the motor reconstruction parameter at the previous moment; determining the shaft control voltage according to the motor reconstruction parameter and the given control command input at the current moment, and determining the shaft control current according to the three-phase collected current and the motor reconstruction parameter; determining the motor control command according to the shaft control voltage, the shaft control current, and the preset electrical machine device parameters to control the motor based on the motor control command. By obtaining the motor reconstruction parameter in the input motor parameter information and the given control command input at the current moment to determine the shaft control voltage, and determining the shaft control current based on the three-phase collected current and the motor reconstruction parameter in the motor parameter information, and finally determining the motor control command based on the shaft control voltage, the shaft control current, and the preset electrical machine device parameters, and then performing motor control. This avoids the phenomenon in the prior art that different parameter acquisition devices need to be used for parameter acquisition before control can be performed. By determining the shaft control voltage and shaft control current through the motor parameter information and the given control command input at the current moment, and then determining the motor control command based on the shaft control voltage, the shaft control current, and the preset electrical machine device parameters, that is, only by collecting the three-phase collected current on the input side of the LC filter, motor control can be achieved, thereby reducing the use of acquisition devices such as rotor position sensors to reduce the cost of motor control with an LC filter.

[0069] In one embodiment, based on the first embodiment of the motor control method with an LC filter, the second embodiment of the present application is proposed. The motor reconstruction parameters include the first estimated motor rotor speed, the first reconstructed motor d-axis current, and the first reconstructed motor q-axis current. The given control instruction includes the given motor rotor speed and the given motor d-axis current. The shaft control voltage includes the d-axis control voltage and the q-axis control voltage. The step of determining the shaft control voltage according to the motor reconstruction parameters and the given control instruction input at the current moment includes:

[0070] Step S21, perform speed loop control based on the first estimated motor rotor speed and the given motor rotor speed to generate the q-axis current;

[0071] Step S22, perform current loop control based on the first reconstructed motor d-axis current and the given motor d-axis current to generate the d-axis control voltage;

[0072] Step S23, perform current loop control based on the first reconstructed motor q-axis current and the q-axis current to generate the q-axis control voltage.

[0073] In this embodiment, the motor reconstruction parameters include the first estimated motor rotor speed, the first reconstructed motor d-axis current, and the first reconstructed motor q-axis current. The given control instruction includes the given motor rotor speed and the given motor d-axis current. The shaft control voltage includes the d-axis control voltage and the q-axis control voltage. Reference can be made to Figure 3 , Figure 3 which is a schematic diagram of the process control of the motor control method with an LC filter according to the present invention. Among them, the sensorless controller of the PMSM (high-speed permanent magnet synchronous motor) with an LC filter based on voltage and current reconstruction in the figure refers to the sum of the inverter voltage reconstructor, the motor current reconstructor, and the position observer based on the dq coordinate system in the following text. As shown in the figure (the parameter values obtained at the previous moment, that is, after the previous control), the first estimated motor rotor speed w e , the first reconstructed motor d-axis current i d and the first reconstructed motor q-axis current i q , the given motor rotor speed w e * and the given motor d-axis current i d * . The two are respectively input by the given speed command and the given method of the d-axis current command. That is, inputting the above two values each time can achieve subsequent control. Furthermore, when determining the first estimated motor rotor speed w e , the first reconstructed motor d-axis current i d , the first reconstructed motor q-axis current i q , the given motor rotor speed w e *and the given d-axis current i of the motor d * After that, the d-axis control voltage u is obtained through calculation d * and the q-axis control voltage u q * , and the calculation process is as follows: Based on the first estimated motor rotor speed w e and the given motor rotor speed w e * Speed loop control is performed to generate the q-axis current i q * , and at the same time, through the first reconstructed d-axis current i of the motor d and the given d-axis current i of the motor d * Current loop control is performed to generate the d-axis control voltage u d * , and then based on the previously obtained q-axis current i q * and the first reconstructed q-axis current i of the motor q Current loop control is performed to generate the said q-axis control voltage u q * . It can be seen from the above that the d-axis control voltage u e * and the q-axis control voltage u d * can be determined based on the given motor rotor speed w e and the given d-axis current i of the motor d as well as the first estimated motor rotor speed w q , the first reconstructed d-axis current i of the motor d * and the first reconstructed q-axis current i of the motor q * . The speed loop control and current loop control described above are both common control methods, and both use a subtractor to subtract the two values and then output to a PI device for proportional integration (the proportional integration parameters of the two are allowed to be different), and then the required parameters are obtained. The above two control methods are conventional speed loop control and current loop control. Furthermore, subsequent control processing can be performed based on the determined axis control voltage. Furthermore, the control of the high-speed permanent magnet synchronous motor can be achieved without using redundant acquisition instruments, and furthermore, the cost of controlling the high-speed permanent magnet synchronous motor with an LC filter is reduced.

[0074] Furthermore, the motor reconstruction parameters include the first estimated motor position. The step of determining the axis control current according to the three-phase sampled current and the motor reconstruction parameters includes:

[0075] Step S23: Based on the three-phase collected current, perform a first current transformation to obtain a first control current, and based on the first control current and the first estimated motor position, perform a second current transformation to obtain an axis control current. Wherein, the first current transformation includes a Clarke transformation, and the second current transformation includes a Park transformation.

[0076] In this embodiment, as Figure 3 , by acquiring the three-phase current i a , i b and i c (i.e., i abc in the figure), and through Clarke transformation, obtain the inverter current i βi and i αi in the two-phase stationary coordinate system (this is the existing Clarke transformation process, and other transformation methods can also be used for substitution). At this time, further processing is carried out. By combining the first estimated motor position θ e * (calculated at the previous moment), perform Park transformation (this is the existing Park transformation process, and other transformation methods can also be used for substitution) to obtain the inverter d-axis current i di and the inverter q-axis current i qi , that is, the axis control current. Then, subsequently, based on the axis control voltage, the axis control current, and the relevant parameters of the motor and the filter, calculate the subsequent control parameters, and then control the motor based on the calculated control parameters, which can achieve motor control without using sensors, thereby reducing the cost of motor control with an LC filter.

[0077] In one embodiment, based on the first embodiment and / or the second embodiment of the motor control method with an LC filter, the third embodiment of the present application is proposed. The step of determining the motor control instruction according to the axis control voltage, the axis control current, and the preset electrical machine device parameters includes:

[0078] Step S31: Determine a reconstructed control current according to the axis control current and the preset electrical machine device parameters, and determine a reconstructed control voltage according to the axis control voltage and the preset electrical machine device parameters;

[0079] In this embodiment, after determining the axis control current and the axis control voltage, the reconstructed control current and the reconstructed control voltage will be determined. Refer to Figure 5 , Figure 5This is a control schematic diagram of an observer and a voltage-current reconstructor in the motor control method with an LC filter according to the present invention. The reconstructed control voltage refers to the voltage value calculated by the reconstructor based on the axis control voltage, and the reconstructed control current refers to the current value calculated by the reconstructor based on the axis control current. That is, the inverter voltage reconstructor determines the reconstructed control voltage based on the axis control voltage and the preset electrical machine device parameters, and the motor current reconstructor determines the reconstructed control current based on the axis control current and the preset electrical machine device parameters. Furthermore, the control instruction of the motor can be obtained after processing based on the reconstructed control current and the reconstructed control voltage.

[0080] Step S32: Construct a position observer in the axis coordinate based on the electrical machine device parameters, and input the axis control voltage and the reconstructed control current into the position observer to obtain the estimated parameters of the motor at the current moment;

[0081] Step S33: Determine the motor control instruction according to the estimated parameters of the motor and the reconstructed control voltage.

[0082] In this embodiment, reference can be made to Figure 4 , Figure 4 This is a circuit schematic diagram of an LC filter in the motor control method with an LC filter according to the present invention. In the figure, it is a three-phase LC filter. The inductance value Lf and capacitance value Cf of the LC filter parameters can be determined when designing the three-phase LC filter, and at the same time, the relevant parameters of the motor, such as the dq-axis inductances Ld and Lq of the motor, the motor flux linkage ψf, and the internal resistance R of the motor, are determined. Furthermore, a position observer in the axis coordinate is constructed based on the above electrical machine device parameters (specifically, Figure 5 the position observer based on the dq coordinate system in Figure 6 ). Reference can be made to Figure 6 This is a control schematic diagram of a position observer based on the dq coordinate system in the motor control method with an LC filter according to the present invention. The figure is a schematic diagram of constructing a position observer in the axis coordinate based on the electrical machine device parameters, and it can also be other control diagrams. Taking this figure as an example, the input signals of the position observer in the axis coordinate are the axis control voltage and the reconstructed control current. It should be noted that the axis control voltage and the reconstructed control current are respectively the voltage and current values of two axes. At this time, a current and voltage value of one axis can be directly randomly input or the current and voltage values of both axes can be input simultaneously to determine the estimated parameters of the motor at the current moment, and the estimated parameters of the motor at the current moment include the rotational speed w e and the position θ e . in In the figure, Lqs + R represents the product of the integral of the q-axis inductance value of the motor and the internal resistance R of the motor, and then the product calculation is performed with the q-axis reconstructed control current calculated at the current moment, and subtracted from the q-axis control voltage u q * Subtraction is also performed in the same way for other blocks, and finally the rotational speed w at the current moment is obtainede , and then multiply it by the reciprocal of the integral to obtain the position θ at the current moment e , where K in the figure i and K P are the custom-set proportional and integral parameters. The above is only a control schematic diagram of the position observer based on the dq coordinate system, and it can also be controlled in other ways, which is not limited here. Furthermore, by inputting the axis control voltage and the reconstructed control current into the position observer, the estimated motor parameters at the current moment can be obtained. Then, based on the estimated motor parameters and the reconstructed control voltage, the motor control command is determined. At the same time, the estimated motor parameters can also provide parameters for the calculation at the next moment, such as the rotational speed w e and the position θ e can provide parameter basis for the calculation at the next moment, thereby ensuring the accurate operation of the entire motor control.

[0083] Further, the reconstructed control voltage includes the q-axis reconstructed control voltage and the d-axis reconstructed control voltage. The step of determining the reconstructed control voltage according to the axis control voltage and the preset electrical machine device parameters includes:

[0084] Step S311, determine the d-axis control voltage in the axis control voltage, and input the d-axis control voltage and the preset electrical machine device parameters into the d-axis voltage reconstruction formula to obtain the d-axis reconstructed control voltage;

[0085] Step S312, determine the q-axis control voltage in the axis control voltage, and input the q-axis control voltage and the preset electrical machine device parameters into the q-axis voltage reconstruction formula to obtain the q-axis reconstructed control voltage.

[0086] In this embodiment, as Figure 5 shown, determining the reconstructed control voltage based on the axis control voltage includes the following two steps: (1) Determine the d-axis control voltage u d * in the axis control voltage, and then input the d-axis control voltage u d * and the preset electrical machine device parameters into the d-axis voltage reconstruction formula to obtain the d-axis reconstructed control voltage u di * , where the d-axis voltage reconstruction formula is the following formula (1).

[0087]

[0088] (2) Determine the q-axis control voltage u q * in the axis control voltage, and then input the q-axis control voltage u q *Input the q-axis voltage reconstruction formula with the preset electrical machine device parameters to obtain the q-axis reconstructed control voltage u qi * , where the q-axis voltage reconstruction formula is the following formula (2).

[0089]

[0090] Among them, the above parameters are the first estimated motor rotor speed w e 、the inductance value Lf and capacitance value Cf of the LC filter parameters, the motor dq-axis inductances Ld and Lq, and the motor magnetic flux ψf. Furthermore, the d-axis reconstructed control voltage u di * and the q-axis reconstructed control voltage u qi * can be determined based on the above formulas (1) and (2), so as to determine the motor control command based on the two reconstructed voltages and the reconstructed current to control the motor.

[0091] Furthermore, the shaft control current includes the d-axis control current and the q-axis control current, the reconstructed control current includes the d-axis reconstructed control current and the q-axis reconstructed control current, and the step of determining the reconstructed control current according to the shaft control current and the preset electrical machine device parameters includes:

[0092] Step S313, determine the d-axis control current in the shaft control current, and input the d-axis control current and the preset electrical machine device parameters into the d-axis current reconstruction formula to obtain the d-axis reconstructed control current;

[0093] Step S314, determine the q-axis control current in the shaft control current, and input the q-axis control current and the preset electrical machine device parameters into the q-axis current reconstruction formula to obtain the q-axis reconstructed control current.

[0094] In this embodiment, as Figure 5 shown, determining the reconstructed control current based on the shaft control current also includes the following two steps: (1) Determine the d-axis control voltage i di in the shaft control current, and then input the d-axis control current i di and the preset electrical machine device parameters into the d-axis current reconstruction formula to obtain the d-axis reconstructed control current i d , where the d-axis current reconstruction formula is the following formula (3).

[0095]

[0096] (3) Determine the q-axis control voltage i qi in the shaft control current, and then input the q-axis control current i qiInput the q - axis current reconstruction formula with the preset electrical machine device parameters to obtain the q - axis reconstructed control current \(i\). q , where the q - axis current reconstruction formula is the following formula (4).

[0097]

[0098] Among them, the above parameters are the first estimated motor rotor speed \(\omega\). e , the capacitance value \(C_f\) of the LC filter parameters, the motor d - q axis inductances \(L_d\) and \(L_q\), and the motor magnetic flux \(\psi_f\). Furthermore, the d - axis reconstructed control current \(i\). d and the q - axis reconstructed control current \(i\). q can be determined based on the above formulas (1) and (2). Then, based on the d - axis reconstructed control voltage \(u\). di * and the q - axis reconstructed control voltage \(u\). qi * as well as the d - axis reconstructed control current \(i\). d and the q - axis reconstructed control current \(i\). q the motor control command is determined to control the motor.

[0099] In one embodiment, based on the first embodiment, the second embodiment, and / or the third embodiment of the motor control method with an LC filter, the fourth embodiment of the present application is proposed. The motor estimated parameters include the second estimated motor rotor speed. The step of determining the motor control command according to the motor estimated parameters and the reconstructed control voltage includes:[[]]

[0100] Step S331: Determine the q - axis reconstructed control voltage and the d - axis reconstructed control voltage in the reconstructed control voltage, and perform a third transformation based on the q - axis reconstructed control voltage, the d - axis reconstructed control voltage, and the second estimated motor rotor speed to obtain a transformed control voltage. Among them, the third transformation includes an inverse Park transformation.[[]]

[0101] Step S332: Adjust the transformed control voltage based on a preset waveform modulation to obtain the motor control command.[[]]

[0102] In this embodiment, after determining the reconstructed control voltage, the q - axis reconstructed control voltage and the d - axis reconstructed control voltage in the reconstructed control voltage are determined, and based on the q - axis reconstructed control voltage \(u\). qi * , the d - axis reconstructed control voltage \(u\). di * and the second estimated motor rotor speed \(\theta\). e perform a third transformation to obtain a transformed control voltage. Among them, referring to.[[]] Figure 3 , the third transformation includes an inverse Park transformation, and the transformed control voltage is the q - axis reconstructed control voltage \(u\) after the inverse Park transformation.qi * and the d-axis reconstructed control voltage u di * , and then based on a preset waveform modulation, the transformed control voltage is adjusted to obtain a motor control command. Among them, the preset waveform modulation is the SVPWM modulation method, and after modulation, a control signal is generated to implement motor control. Furthermore, motor control is achieved only by collecting three-phase current values, which can reduce the motor control cost with an LC filter.

[0103] Further, after the step of inputting the axis control voltage and the reconstructed control current into the position observer to obtain the motor estimated parameters at the current moment, it includes:

[0104] Step S321, taking the reconstructed control current and the motor estimated parameters as the current motor reconstructed parameters at the current moment, and at the next moment, executing the step of obtaining the input motor parameter information, and updating the current motor reconstructed parameters to the motor reconstructed parameters of the previous moment.

[0105] In this embodiment, after determining the reconstructed control current and the motor estimated parameters, the reconstructed control current and the motor estimated parameters will be updated to the motor reconstructed parameters of the previous moment at the next moment corresponding to the current moment, and the step of obtaining the input motor parameter information will be executed. Furthermore, the cyclic control of the motor is realized, ensuring the accuracy of motor control at each time sequence. Moreover, at each moment, only the reconstructed control current and the motor estimated parameters of the previous moment and the collected three-phase current are required to complete the motor control, which can realize motor control without using a large number of sensors, and thus reduce the motor control cost with an LC filter.

[0106] Corresponding to the above embodiment, the present invention also proposes a frequency converter 100.

[0107] The frequency converter 100 of the embodiment of the present invention includes an LC filter 130 and an inverter 120. The output end of the LC filter 130 is connected to the motor 200, and the input end of the LC filter 130 is connected to the output end of the inverter 120;

[0108] A controller 110, the controller 110 is connected to the input end of the inverter 120;

[0109] The controller 110 is used to execute the steps of the motor control method with an LC filter as described above.

[0110] According to the controller 110 of an embodiment of the present invention, when the processor executes a program, it implements the above-mentioned motor control method with an LC filter. Based on the above-mentioned motor control method with an LC filter, by obtaining the input motor parameter information, wherein the motor parameter information includes the three-phase sampled current on the input side of the LC filter and the motor reconstruction parameters at the previous moment; determining the shaft control voltage according to the motor reconstruction parameters and the given control instruction input at the current moment, and determining the shaft control current according to the three-phase sampled current and the motor reconstruction parameters; determining the motor control instruction according to the shaft control voltage, the shaft control current and the preset electrical device parameters, so as to control the motor based on the motor control instruction. Furthermore, through the above control, it is only necessary to collect the three-phase sampled current on the input side of the LC filter to realize motor control, thereby reducing the use of acquisition devices such as rotor position sensors, so as to reduce the motor control cost with an LC filter.

[0111] Corresponding to the above embodiment, the present invention also proposes a motor control system.

[0112] As Figure 7 shown, it is a schematic diagram of a module of the motor control system of the present invention. The motor control system of an embodiment of the present invention may include: a motor 200;

[0113] An inverter 100, the output end of the LC filter 130 in the inverter 100 is connected to the motor 200, and the input end of the controller 110 in the inverter 100 is connected to the power grid;

[0114] The inverter 100 is used to execute the steps of the above-mentioned motor control method with an LC filter, and is used to obtain the input motor parameter information, wherein the motor parameter information includes the three-phase sampled current on the input side of the LC filter and the motor reconstruction parameters at the previous moment; determining the shaft control voltage according to the motor reconstruction parameters and the given control instruction input at the current moment, and determining the shaft control current according to the three-phase sampled current and the motor reconstruction parameters; determining the motor control instruction according to the shaft control voltage, the shaft control current and the preset electrical device parameters, so as to control the motor based on the motor control instruction. Furthermore, through the above control, it is only necessary to collect the three-phase sampled current on the input side of the LC filter to realize motor control, thereby reducing the use of acquisition devices such as rotor position sensors, so as to reduce the motor control cost with an LC filter.

[0115] The present invention also provides an inverter. Refer to Figure 8 , Figure 8 shown in the schematic diagram of the inverter module of the present invention. The inverter includes:

[0116] Parameter acquisition module A01 is used to acquire the input motor parameter information. Among them, the motor parameter information includes the three-phase collected current on the input side of the LC filter and the motor reconstruction parameters at the previous moment.

[0117] Parameter determination module A02 is used to determine the shaft control voltage according to the motor reconstruction parameters and the given control instruction input at the current moment, and determine the shaft control current according to the three-phase collected current and the motor reconstruction parameters.

[0118] Instruction determination module A03 is used to determine the motor control instruction according to the shaft control voltage, the shaft control current and the preset electrical device parameters, so as to control the motor based on the motor control instruction.

[0119] The parameter determination module A02 is further used for:

[0120] Perform speed loop control based on the first estimated motor rotor speed and the given motor rotor speed to generate the q-axis current.

[0121] Perform current loop control based on the first reconstructed motor d-axis current and the given motor d-axis current to generate the d-axis control voltage.

[0122] Perform current loop control based on the first reconstructed motor q-axis current and the q-axis current to generate the q-axis control voltage.

[0123] The parameter determination module A02 is further used for:

[0124] Perform the first current transformation on the three-phase collected current to obtain the first control current, and perform the second current transformation on the first control current and the first estimated motor position to obtain the shaft control current. Among them, the first current transformation includes Clarke transformation, and the second current transformation includes Park transformation.

[0125] The instruction determination module A03 is further used for:

[0126] Determine the reconstructed control current according to the shaft control current and the preset electrical device parameters, and determine the reconstructed control voltage according to the shaft control voltage and the preset electrical device parameters.

[0127] Construct a position observer in the shaft coordinate based on the electrical device parameters, and input the shaft control voltage and the reconstructed control current into the position observer to obtain the motor estimated parameters at the current moment.

[0128] Determine the motor control instruction according to the motor estimated parameters and the reconstructed control voltage.

[0129] The instruction determination module A03 is further used for:

[0130] Determine the d-axis control voltage in the shaft control voltage, and input the d-axis control voltage and the preset electrical machine device parameters into the d-axis voltage reconstruction formula to obtain the d-axis reconstructed control voltage;

[0131] Determine the q-axis control voltage in the shaft control voltage, and input the q-axis control voltage and the preset electrical machine device parameters into the q-axis voltage reconstruction formula to obtain the q-axis reconstructed control voltage.

[0132] The instruction determination module A03 is further configured to:

[0133] Determine the q-axis reconstructed control voltage and the d-axis reconstructed control voltage in the reconstructed control voltage, and perform a third transformation based on the q-axis reconstructed control voltage, the d-axis reconstructed control voltage, and the second estimated motor rotor speed to obtain a transformed control voltage, where the third transformation includes an inverse Park transformation;

[0134] Adjust the transformed control voltage based on a preset waveform modulation to obtain a motor control instruction.

[0135] The instruction determination module A03 is further configured to:

[0136] Determine the d-axis control current in the shaft control current, and input the d-axis control current and the preset electrical machine device parameters into the d-axis current reconstruction formula to obtain the d-axis reconstructed control current;

[0137] Determine the q-axis control current in the shaft control current, and input the q-axis control current and the preset electrical machine device parameters into the q-axis current reconstruction formula to obtain the q-axis reconstructed control current.

[0138] The instruction determination module A03 is further configured to:

[0139] Take the reconstructed control current and the motor estimated parameters as the current motor reconstructed parameters at the current moment, and execute the step of obtaining the input motor parameter information at the next moment, and update the current motor reconstructed parameters to the motor reconstructed parameters at the previous moment.

[0140] The present invention also provides a storage medium, and this storage medium is a computer storage medium.

[0141] The motor control program with an LC filter is stored on the storage medium of the present invention, and when the motor control program with an LC filter is executed by a processor, the steps of the motor control method with an LC filter as described above are implemented.

[0142] Among them, when the motor control program with an LC filter running on the processor is executed, the implemented method can refer to each embodiment of the motor control method with an LC filter of the present invention, which will not be elaborated here.

[0143] It should be noted that in this article, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such a process, method, article or system. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method, article or system including this element.

[0144] The serial numbers of the above embodiments of the present invention are only for description and do not represent the superiority or inferiority of the embodiments.

[0145] The above are only optional embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made by using the content of the specification and drawings of the present invention under the inventive concept of the present invention, or direct / indirect application in other related technical fields is included in the patent protection scope of the present invention.

Claims

1. A motor control method with an LC filter, characterized in that: The motor control method with LC filter comprises the following steps: Acquire input motor parameter information, wherein the motor parameter information includes the three-phase collected current on the input side of the LC filter and the motor reconstruction parameters at the previous moment; Determine the shaft control voltage according to the motor reconstruction parameter and the given control instruction input at the current moment, and determine the shaft control current according to the three-phase collected current and the motor reconstruction parameter; A motor control instruction is determined according to the shaft control voltage, the shaft control current and preset motor component parameters, so as to control the motor based on the motor control instruction.

2. The motor control method with an LC filter according to claim 1, wherein: The motor reconstruction parameters include a first estimated motor rotor speed, a first reconstructed motor d-axis current, and a first reconstructed motor q-axis current; the given control instruction includes a given motor rotor speed and a given motor d-axis current; the axis control voltage includes a d-axis control voltage and a q-axis control voltage; and the step of determining the axis control voltage according to the motor reconstruction parameters and the given control instruction input at a current moment includes: Performing speed loop control based on the first estimated motor rotor speed and the given motor rotor speed to generate a q-axis current; Performing current loop control based on the first reconstructed motor d-axis current and the given motor d-axis current to generate the d-axis control voltage; The q-axis control voltage is generated by performing current loop control based on the first reconstructed motor q-axis current and the q-axis current.

3. The motor control method with an LC filter according to claim 1, wherein: The motor reconstruction parameter includes a first estimated motor position, and the step of determining the shaft control current according to the three-phase collected current and the motor reconstruction parameter includes: A first current transformation is performed based on the three-phase collected current to obtain a first control current, and a second current transformation is performed based on the first control current and the first estimated motor position to obtain an axis control current, wherein the first current transformation includes a Clarke transformation and the second current transformation includes a Park transformation.

4. The motor control method with an LC filter according to claim 1, wherein: The step of determining the motor control instruction according to the shaft control voltage, the shaft control current and preset motor device parameters includes: Determining a reconstruction control current according to the axis control current and preset motor device parameters, and determining a reconstruction control voltage according to the axis control voltage and preset motor device parameters; Constructing a position observer of the axis coordinates based on the motor device parameters, and inputting the axis control voltage and the reconstructed control current into the position observer to obtain the estimated motor parameters at the current moment; A motor control instruction is determined according to the motor estimated parameters and the reconstructed control voltage.

5. The motor control method with an LC filter according to claim 4, wherein: The reconstructed control voltage includes a q-axis reconstructed control voltage and a d-axis reconstructed control voltage. The step of determining the reconstructed control voltage according to the axis control voltages and preset motor device parameters includes: Determining a d-axis control voltage among the axis control voltages, and inputting the d-axis control voltage and the preset motor device parameters into a d-axis voltage reconstruction formula to obtain the d-axis reconstructed control voltage; A q-axis control voltage among the axis control voltages is determined, and the q-axis control voltage and the preset motor device parameters are input into a q-axis voltage reconstruction formula to obtain the q-axis reconstructed control voltage.

6. The motor control method with an LC filter according to claim 4, wherein: The motor estimated parameter includes a second estimated motor rotor speed, and the step of determining the motor control instruction according to the motor estimated parameter and the reconstructed control voltage includes: determining a q-axis reconstructed control voltage and a d-axis reconstructed control voltage in the reconstructed control voltage, and performing a third transformation based on the q-axis reconstructed control voltage, the d-axis reconstructed control voltage, and the second estimated motor rotor speed to obtain a transformed control voltage, wherein the third transformation includes an inverse Park transformation; The conversion control voltage is adjusted based on a preset waveform modulation to obtain a motor control instruction.

7. The motor control method with an LC filter according to claim 4, wherein: The axis control current includes a d-axis control current and a q-axis control current, the reconstructed control current includes a d-axis reconstructed control current and a q-axis reconstructed control current, and the step of determining the reconstructed control current according to the axis control current and preset motor device parameters includes: Determining the d-axis control current among the axis control currents, and inputting the d-axis control current and the preset motor device parameters into a d-axis current reconstruction formula to obtain the d-axis reconstructed control current; The q-axis control current among the axis control currents is determined, and the q-axis control current and the preset motor device parameters are input into a q-axis current reconstruction formula to obtain the q-axis reconstructed control current.

8. The motor control method with an LC filter according to claim 4, wherein: After the step of inputting the shaft control voltage and the reconstructed control current into the position observer to obtain the motor estimated parameters at the current moment, the method includes: The reconstructed control current and the motor estimated parameters are used as the current motor reconstruction parameters at the current moment, and the step of obtaining the input motor parameter information is performed at the next moment, and the current motor reconstruction parameters are updated to the motor reconstruction parameters at the previous moment.

9. A frequency converter, characterized in that: The frequency converter comprises: An LC filter and an inverter, wherein the output end of the LC filter is connected to the motor, and the input end of the LC filter is connected to the output end of the inverter; A controller connected to an input terminal of the inverter; The controller is used to execute the steps of the motor control method with LC filter according to any one of claims 1 to 8.

10. A motor control system, characterized in that: include: Motor; A frequency converter, wherein an output end of an LC filter in the frequency converter is connected to the motor, and an input end of a controller in the frequency converter is connected to a power grid; The frequency converter is further configured to execute the steps of the motor control method with an LC filter as claimed in any one of claims 1 to 8.

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