CN114301348B - A pulse high frequency injection control method and control system without position sensor - Google Patents

Abstract

The invention provides a control method and a control system for pulse vibration high-frequency injection position-free sensor, which can obtain high-frequency inductance L _dh through d-axis current I _d and q-axis current I _q in the current running state, and then calculate and obtain high-frequency voltage U _dhref to be injected through high-frequency inductance L _dh; or directly sampling the actual high-frequency current I _dh, and outputting a target high-frequency voltage U _dhref through a difference delta I _dh between the target high-frequency current I _dhref and the actual high-frequency current I _dh; or the target frequency voltage U _dhref is directly obtained by calculation of the d-axis current I _d and the q-axis current I _q under the current running state through the deep learning neural network, and the high frequency voltage U _dhref obtained by the three modes can enable the actual high frequency current I _dh to be in a preset range and not to be higher or lower, so that the noise problem and the signal extraction difficulty problem of the system can be avoided.

Description

A pulse high frequency injection control method and control system without position sensor

Technical Field

The present invention relates to the technical field of permanent magnet synchronous motors, and in particular to a pulse high frequency injection position sensorless control method and control system.

Background technique

Permanent magnet synchronous motors with high performance speed control generally require position sensors, such as rotary encoders, photoelectric encoders, etc. Installing position sensors is not only costly, bulky, and has low mechanical reliability, but also causes concentricity problems during installation. Using a highly reliable position sensorless control algorithm is an effective solution.

Existing position sensorless control methods for six-phase permanent magnet synchronous motors based on motor back EMF fail when the motor runs at low speed or zero speed because the motor back EMF is very small or zero.

When the permanent magnet synchronous motor runs at zero speed, a high-frequency voltage signal injection algorithm based on the motor salient pole effect is often used. Different forms of voltage signals can be injected in different reference coordinate systems. Among them, the more mature one is the high-frequency pulse square wave voltage signal injection method.

The pulse high-frequency voltage injection method is to inject a high-frequency sinusoidal voltage signal into the direct axis of the estimated two-phase rotating coordinate system, thereby generating a high-frequency pulse magnetic field. This voltage signal can excite the motor to produce an inductance saturation effect, making the surface-mounted permanent magnet synchronous motor present "salient polarity". By detecting the high-frequency current response containing the rotor position information and demodulating this response signal, the rotor position and speed can be obtained, thereby realizing position sensorless control. The position sensorless control method based on high-frequency signal injection relies on the salient pole characteristics of the motor, does not rely on motor parameters and back electromotive force, and realizes high-precision control at low speed and zero speed through position estimation, so it has broad application prospects.

Referring to FIG1 , a commonly used pulse high-frequency injection method injects a high-frequency voltage U _dh into the d-axis. When a high-frequency voltage U _dh with a constant amplitude is injected, when the fundamental current Id* at the operating point becomes smaller, the magnetic saturation degree of the motor decreases, L _dh increases, and the high-frequency current I _dh becomes smaller, which will cause difficulty in signal extraction; and when the fundamental current Id* at the operating point becomes larger, the magnetic saturation degree of the motor increases, L _dh decreases, and the high-frequency current I _dh increases, which will cause noise problems in the control system.

Summary of the invention

In order to overcome the above technical defects, the object of the present invention is to provide a control method and control system for pulsed high-frequency injection without position sensor, which can keep the high-frequency current basically unchanged.

The present invention discloses a pulse high-frequency injection position sensorless control method, comprising the following steps: setting a preset range of high-frequency current I _dh fluctuation; obtaining a d-axis current I _d and a q-axis current I _q of an inverter of a permanent magnet synchronous motor in a current operating state, and obtaining an inductance L _dh in a current operating state through the d-axis current I _d and the q-axis current I _q ; adjusting a high-frequency voltage U _dh according to a formula I _dh =U _dh /ωh·L _dh so that the high-frequency current I _dh does not exceed a preset range, wherein ωh·L _dh is a d-axis high-frequency impedance of the motor, and ωh is a high-frequency injection frequency; or setting a target high-frequency current I _dhref , sampling an actual high-frequency current I _dh in real time, and obtaining a difference ΔI _dh between the target high-frequency current I _dhref and the actual high-frequency current I _dh , and inputting the difference ΔI _dh into a closed-loop regulator, wherein the closed-loop regulator outputs a target high-frequency voltage U _dhref , and according to the target high-frequency voltage U The high-frequency voltage is injected according to the value of _dhref ; or the d-axis current I _d and the q-axis current I q of the permanent magnet synchronous motor inverter in the current operating state are obtained, and the target high-frequency voltage U _dh corresponding to the current d-axis current I _d and the q-axis current I _q is obtained through deep learning neural network calculation, _and the high-frequency voltage is injected according to the value of the target high-frequency voltage U _dhref .

Preferably, obtaining the inductance L _dh in the current operating state through the d-axis current I _d and the q-axis current I _q includes: establishing an offline table of d-axis current I _d , q-axis current I _q and inductance L _dh , and finding the inductance L _dh corresponding to different d-axis currents I _d and q-axis currents I _q according to the offline table.

Preferably, the establishing of the offline table of the d-axis current I _d , the q-axis current I _q and the inductance L _dh comprises: obtaining a data set of corresponding relationships between the d-axis current I _d , the q-axis current I _q and the inductance Ldh through motor simulation, and establishing the offline table through the data set of corresponding relationships; or obtaining a data set of corresponding relationships between the d-axis current I _d , the q-axis current I _q and the inductance Ldh through offline testing, and establishing the offline table through the data set of corresponding relationships.

Preferably, the step of adjusting the high-frequency voltage U _dh according to the formula I _dh =U _dh /ωh·L _dh so that the change value of the high-frequency current I _dh at any time does not exceed the preset change value includes: adjusting the high-frequency voltage U _dh at intervals of preset time periods so that the high-frequency current I _dh at any time does not exceed the preset range, or so that the high-frequency current I _dh after each adjustment does not exceed the preset range.

Preferably, the step of adjusting the high-frequency voltage U _dh at intervals of preset time periods so that the high-frequency current I _dh at any time does not exceed a preset range includes: real-time monitoring of the high-frequency current I _dh , and if the current high-frequency current I _dh exceeds the preset range, adjusting the current high-frequency current I _dh by a regulator so that the current high-frequency current I _dh is within the preset range.

Preferably, the obtaining of the high-frequency voltage U _dh corresponding to different d-axis currents I _d and q-axis currents I _q by calculating through a deep learning neural network includes: the neural network learning: the high-frequency voltage U _dh corresponding to different d-axis currents I _d and q-axis currents I _q within the preset range of the high-frequency current I _dh ; and obtaining the corresponding high-frequency voltage U _dh according to the different d-axis currents I _d and q-axis currents I _q .

The present invention also discloses a pulse high-frequency injection position sensorless control system, comprising a processing module and a neural network module connected to each other; the processing module sets a preset range of high-frequency current I _dh fluctuations, and obtains the d-axis current I _d and the q-axis current I _q of the inverter of the permanent magnet synchronous motor in the current operating state, and obtains the inductance L _dh in the current operating state through the d-axis current I _d and the q-axis current I _q ; the high-frequency voltage U _dh is adjusted according to the formula I _dh =U _dh /ωh·L _dh so that the high-frequency current I _dh does not exceed the preset range, wherein ωh·L _dh is the d-axis high-frequency impedance of the motor, and ωh is the high-frequency injection frequency; or the processing module sets a target high-frequency current I _dhref , samples the actual high-frequency current I _dh in real time, and obtains the difference ΔI _dh between the target high-frequency current I _dhref and the actual high-frequency current I _dh , and inputs the difference ΔI _dh into a closed-loop regulator, the closed-loop regulator outputs a target high-frequency voltage U _dhref , and according to the target high-frequency voltage U The high-frequency voltage is injected according to the value of _dhref ; or the processing module obtains the d-axis current I _d and the q-axis current I _q of the inverter of the permanent magnet synchronous motor in the current operating state, and obtains the target high-frequency voltage U _dh corresponding to the current d-axis current I _d and the q-axis current I _q through deep learning neural network calculation, and injects the high-frequency voltage according to the value of the target high-frequency voltage U _dhref .

Compared with the prior art, the above technical solution has the following beneficial effects:

1. Whether first obtaining the high-frequency inductance L _dh through the d-axis current I _d and the q-axis current I _q in the current operating state, and then calculating the high-frequency voltage U _dhref to be injected through the high-frequency inductance L _dh ; or directly sampling the actual high-frequency current I _dh , and outputting the target high-frequency voltage U _dhref through the difference ΔI _dh between the target high-frequency current I dhref and the actual high-frequency current I _dh ; or directly calculating the target high-frequency voltage U _dhref based on the d-axis current I _d and the q-axis current I _q in the current operating state through a deep learning neural network, the high-frequency voltage U _dhref obtained by these three _methods will make the actual high-frequency current I _dh within the preset range, and will not be too high or too low, so the noise problem of the system and the difficulty of signal extraction can be avoided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a flow chart of a control method for pulse high frequency injection without position sensor provided by the present invention;

FIG2 is a control flow chart of the present invention for inputting the difference between the target high-frequency current value I _dhref and the sampled high-frequency current value I _dh into the closed-loop regulator to adjust the amplitude of U _dh in real time.

Detailed ways

The advantages of the present invention are further described below in conjunction with the accompanying drawings and specific embodiments.

Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

The terms used in this disclosure are for the purpose of describing specific embodiments only and are not intended to limit the disclosure. The singular forms "a", "the" and "the" used in this disclosure and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and/or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

It should be understood that although the terms first, second, third, etc. may be used in the present disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present disclosure, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

In the description of the present invention, it is necessary to understand that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection of two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

In the following description, the suffixes such as "module", "component" or "unit" used to represent elements are only used to facilitate the description of the present invention, and have no specific meanings. Therefore, "module" and "component" can be used interchangeably.

The present invention discloses a control method for pulse high-frequency injection without position sensor. The high-frequency voltage U _dh is adjusted to keep the high-frequency current I _dh basically unchanged, thereby avoiding the system noise problem and signal extraction difficulty caused by the high-frequency current I _dh being too high or too low. The present invention provides three methods for adjusting the high-frequency voltage U _dh .

The first method is to obtain the high-frequency voltage U _dh by formula calculation, and adjust the high-frequency current I _dh by adjusting the high-frequency voltage U _dh so that it does not exceed the preset range. Specifically:

Setting a preset range of fluctuation of the high-frequency current I _dh , which is a range in which the high-frequency current I _dh will not cause system noise problems and signal extraction difficulties;

Obtaining the d-axis current I _d and the q-axis current I _q of the inverter of the permanent magnet synchronous motor in the current operating state, and obtaining the inductance L _dh in the current operating state through the d-axis current I _d and the q-axis current I _q ;

According to the formula I _dh =U _dh /ωh·L _dh (where ωh·L _dh is the d-axis high-frequency impedance of the motor, and ωh is the high-frequency injection frequency), it can be known that when a high-frequency voltage U _dh with a constant amplitude is injected, the magnitude of the high-frequency current I _dh is inversely proportional to the inductance L _dh . When the inductance L _dh is known, the value of the high-frequency current I _dh can be output. Therefore, the high-frequency current I _{dh can be adjusted by adjusting the high-frequency voltage U dh so} that the high-frequency current I _dh does not exceed a preset range.

Preferably, the inductance L _dh in the current operating state is obtained through the d-axis current I _d and the q-axis current I _q , and an offline table of the d-axis current I _d , the q-axis current I _q and the inductance L _dh can be established, and the inductance L _dh corresponding to different d-axis currents I _d and q-axis currents I _q can be found according to the offline table.

Specifically, a corresponding relationship data set between the d-axis current I _d , the q-axis current I _q and the inductance Ldh is obtained through motor simulation, and an offline table is established through the corresponding relationship data set. Alternatively, a corresponding relationship data set between the d-axis current I _d , the q-axis current I _q and the inductance Ldh is obtained through offline testing, and an offline table is established through the corresponding relationship data set.

Preferably, by adjusting the high-frequency voltage U _dh at intervals of a preset time period, the high-frequency current I _dh at any time can be made not to exceed a preset range, or the high-frequency current I _dh after each adjustment can be made not to exceed a preset range.

It can be understood that there are two adjustment results. One is to simply ensure that the high-frequency current I _dh does not exceed the preset range after each adjustment. The other is to ensure that the high-frequency current I _dh does not exceed the preset range after each adjustment, and also to ensure that the time between each adjustment process, the high-frequency current I _dh does not exceed the preset range. This requires a real-time monitoring mechanism.

Specifically, when the high-frequency current I _dh at any time does not exceed a preset range, the high-frequency current I _dh can be monitored in real time. If the current high-frequency current I _dh exceeds the preset range, the current high-frequency current I _dh is adjusted by a regulator so that the current high-frequency current I _dh is within the preset range.

The second method is to set the target high-frequency current I _dhref , see FIG2 , collect current data from the motor in real time, obtain the d-axis current I _d through the coordinate transformation from the abc natural coordinate axis to the dq axis, filter the d-axis current I _d through a high-pass filter to obtain the actual high-frequency current I _dh , and then obtain the difference ΔI _dh between the target high-frequency current I _dhref and the actual high-frequency current I _dh , input the difference ΔI _dh into the closed-loop regulator, and the closed-loop regulator outputs the target high-frequency voltage U _dhref , transform the value of the target high-frequency voltage U _dhref from the dq axis to the abc natural coordinate axis, and finally input it into the motor through the controller.

The second method obtains the amplitude of the high-frequency current I _dh by current sampling. The difference between the target high-frequency current value I _dhref and the sampled high-frequency current value I _dh is input into the closed-loop regulator, and the amplitude of U _dh is adjusted in real time to keep the high-frequency current I _dh constant.

The third method is to obtain the d-axis current I _d and q-axis current I _q of the permanent magnet synchronous motor inverter under the current operating state, and then directly calculate and output the target high-frequency voltage U _dh corresponding to the current d-axis current I _d and q-axis current I _q through the deep learning neural network, and finally inject the high-frequency voltage according to the value of the target high-frequency voltage U _dhref .

First, the neural network learning process must be carried out. The early stage includes collecting a large amount of test data or actual working data to form a training set data, and training is carried out through the training set data. The training set data includes the high-frequency voltage U _dh corresponding to different d-axis currents I _d and q-axis currents I _q within the preset range of the high-frequency current I _dh , and the high-frequency voltage U _dh corresponding to different d-axis currents I _d and q-axis currents I _q .

The present invention also discloses a pulse high frequency injection position sensorless control system, which includes a processing module and a neural network module connected to each other. The processing module can be understood as a motor controller.

The preset range of fluctuation of the high-frequency current I _dh can be set through the processing module, and the d-axis current I _d and the q-axis current I _q of the inverter of the permanent magnet synchronous motor in the current operating state are obtained, and the inductance L _dh in the current operating state is obtained through the d-axis current I _d and the q-axis current I _q ; the high-frequency voltage U _dh is adjusted according to the formula I _dh =U _dh /ωh·L _dh so that the high-frequency current I _dh does not exceed the preset range, where ωh·L _dh is the d-axis high-frequency impedance of the motor, and ωh is the high-frequency injection frequency.

The processing module can also set a target high-frequency current I _dhref , sample the actual high-frequency current I _dh in real time, and obtain a difference ΔI _dh between the target high-frequency current I _dhref and the actual high-frequency current I _dh , input the difference ΔI _dh into a closed-loop regulator, and the closed-loop regulator outputs a target high-frequency voltage U _dhref , and injects a high-frequency voltage according to the value of the target high-frequency voltage U _dhref .

The processing module can also be used to obtain the d-axis current I _d and the q-axis current I _q of the permanent magnet synchronous motor inverter in the current operating state, and obtain the target high-frequency voltage U _dh corresponding to the current d-axis current I _d and q-axis current I _q through deep learning neural network calculation, and inject the high-frequency voltage according to the value of the target high-frequency voltage U _dhref .

The above three methods can achieve the purpose of ensuring that the high-frequency current I _dh remains basically unchanged, avoiding the system noise problem and signal extraction difficulty caused by large fluctuations of the high-frequency current I _dh .

It should be noted that the embodiments of the present invention have better practicability and do not impose any form of limitation on the present invention. Any technician familiar with the field may use the technical content disclosed above to change or modify it into an equivalent effective embodiment. However, any modification or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention, as long as it does not deviate from the content of the technical solution of the present invention, are still within the scope of the technical solution of the present invention.

Claims (4)

1. A pulse high frequency injection control method without position sensor, characterized in that it comprises the following steps: A preset range of fluctuation of the high-frequency current I _dh is set; a d-axis current I _d and a q-axis current I _q of the inverter of the permanent magnet synchronous motor in the current operating state are obtained, and the inductance L _dh in the current operating state is obtained through the d-axis current I _d and the q-axis current I _q ; the high-frequency voltage U _dh is adjusted according to the formula I _dh =U _dh ωh·L _dh so that the high-frequency current I _dh does not exceed the preset range, wherein ωh·L _dh is the d-axis high-frequency impedance of the motor, and ωh is the high-frequency injection frequency, including: adjusting the high-frequency voltage U _dh at intervals of a preset time period so that the high-frequency current I _dh at any time does not exceed the preset range, or the high-frequency current I _dh after each adjustment does not exceed the preset range; real-time monitoring of the high-frequency current I _dh , if the current high-frequency current I _dh exceeds the preset range, adjusting the current high-frequency current I _dh through a regulator so that the current high-frequency current I _dh is within the preset range. 2. The control method according to claim 1, characterized in that the step of obtaining the inductance L _dh in the current operating state through the d-axis current I _d and the q-axis current I _q comprises: An offline table of the d-axis current I _d , the q-axis current I _q and the inductance L _dh is established, and the inductance L _dh corresponding to different d-axis currents I _d and q-axis currents I _q is found according to the offline table. 3. The control method according to claim 2, characterized in that the establishing of the offline table of the d-axis current I _d , the q-axis current I _q and the inductance L _dh comprises: Acquire a corresponding relationship data set between the d-axis current I _d , the q-axis current I _q and the inductance Ldh through motor simulation, and establish the offline table through the corresponding relationship data set; Alternatively, a corresponding relationship data set between the d-axis current I _d , the q-axis current I _q and the inductance Ldh is obtained through an offline test, and the offline table is established through the corresponding relationship data set. 4. A pulse high frequency injection position sensorless control system, characterized by comprising a processing module and a neural network module connected to each other; The processing module sets a preset range of fluctuation of the high-frequency current I _dh , obtains the d-axis current I _d and the q-axis current I _q of the inverter of the permanent magnet synchronous motor in the current operating state, and obtains the inductance L _dh in the current operating state through the d-axis current I _d and the q-axis current I _q ; adjusts the high-frequency voltage U _dh according to the formula I _dh =U _dh ωh·L _dh so that the high-frequency current I _dh does not exceed the preset range, wherein ωh·L _dh is the d-axis high-frequency impedance of the motor, and ωh is the high-frequency injection frequency, including: adjusting the high-frequency voltage U _dh at intervals of a preset time period so that the high-frequency current I _dh at any time does not exceed the preset range, or the high-frequency current I _dh after each adjustment does not exceed the preset range; monitors the high-frequency current I _dh in real time, and if the current high-frequency current I _dh exceeds the preset range, adjusts the current high-frequency current I _dh through a regulator so that the current high-frequency current I _dh is within the preset range.