Phase current reconstruction method for open-winding doubly salient motor

Abstract

The invention relates to the technical field of motor control, in particular to an open-winding doubly salient motor phase current reconstruction method, which comprises the following steps of: S1, removing three phase current sensors in a three-phase H-bridge converter, arranging one current sensor on a direct-current bus of the three-phase H-bridge converter, and setting a measured value of the current sensor as iLEM1; s2, adjusting a chopping strategy of the driving system to be a PWM-PWM mode; s3, the rotor position angle of the motor is obtained in real time, the sector where the rotor is located is judged according to the rotor position angle, the rotor position angle interval ranging from 0 degree to 120 degrees is the first sector, the rotor position angle interval ranging from 120 degrees to 240 degrees is the second sector, and the rotor position angle interval ranging from 240 degrees to 360 degrees is the third sector; and S4, in combination with the working principle of the open-winding doubly salient motor, phase current reconstruction is carried out through the relationship between the phase current in different current loops in different sectors and the iLEM1. Compared with a motor system comprising three phase current sensors, the motor system provided by the invention only needs one current sensor, so that the system cost is reduced, and the reliability of the motor system is also improved.

Description

Technical Field

[0001] The present application relates to the field of motor control technology, and in particular to a phase current reconstruction method for an open-winding double-pole motor. Background Art

[0002] Open-winding doubly salient motors, due to their simple structure and strong fault tolerance, hold great promise for applications in fields such as electric vehicles and aviation. Accurate torque control relies on obtaining motor phase currents. For open-winding motors, this typically requires a current sensor connected in series with each phase winding to measure the phase current. This method of obtaining phase currents not only increases the number of sensors, especially for multi-phase motors, but also reduces system reliability. Therefore, it is necessary to consider methods that can obtain the actual phase currents of the system with fewer current sensors. However, to the author's knowledge, no phase current reconstruction methods are currently available for open-winding doubly salient motors. Regarding Y-connected doubly salient motors, Chen Xu et al.'s patent, "A Phase Current Reconstruction Method for Hybrid-Excitation Doubly Salient Motors" (China, Publication Date: January 5, 2024, Publication Number: CN113517842B), describes a phase current reconstruction method based on a single current sensor. This method alters the bridge converter topology, wrapping the C-phase winding and part of the bridge arm in a current sensor. This method, combined with the operating principle of a DSEM (Direct Current Emitting Diode), achieves three-phase current reconstruction.

[0003] However, although the above method can realize phase current reconstruction, it is only applicable to Y-connected double-pole motors and is not applicable to open-winding double-pole motors. In addition, although the above method only requires one current sensor, it changes the inverter topology, which not only increases the hardware complexity but also cannot be applied to integrated power modules.

[0004] Therefore, it is necessary to provide an improved technical solution to the above-mentioned deficiencies in the prior art. Summary of the Invention

[0005] The purpose of this application is to provide a phase current reconstruction method for an open-winding double-pole motor to solve or alleviate the problems existing in the above-mentioned prior art.

[0006] In order to achieve the above objectives, this application provides the following technical solutions: A method for reconstructing phase current of an open-winding doubly salient motor, comprising: Step S1: Remove the three phase current sensors in the three-phase H-bridge converter, set a current sensor on the DC bus of the three-phase H-bridge converter and set its measured value as i LEM1 ; Step S2: Adjust the chopping strategy of the drive system to PWM-PWM mode; Step S3: acquiring the motor rotor position angle in real time, and determining the sector of the rotor according to the rotor position angle, wherein the rotor position angle interval of 0° to 120° is the first sector, the rotor position angle interval of 120° to 240° is the second sector, and the rotor position angle interval of 240° to 360° is the third sector; Step S4: Combined with the working principle of the open-winding doubly salient motor, the phase currents in different current loops in different sectors and i LEM1 The phase current is reconstructed based on the relationship between

[0007] Preferably, the step S3 further includes: When the rotor is in the first sector, the H-bridge converter switch tube T where the A-phase winding is located A1 , switch tube T A4 Participate in the control work, the H-bridge converter switch tube T where the C phase winding is located C2 , switch tube T C3 Participate in the control work, the H-bridge converter where the B-phase winding is located does not work; When the rotor is in the second sector, the H-bridge converter switch tube T where the A-phase winding is located A2 , switch tube T A3 Participate in the control work, the H-bridge converter switch tube T where the B phase winding is located B1 , switch tube T B4 Participate in the control work, the H-bridge converter where the C-phase winding is located does not work; When the rotor is in the third sector, the H-bridge converter switch tube T where the B-phase winding is located B2 , switch tube T B3 Participate in the control work, the H-bridge converter switch tube T where the C phase winding is located C1 , switch tube T C4 Participates in the control work, and the H-bridge converter where the A-phase winding is located does not work.

[0008] Preferably, in step S1, the current sensor is installed at the positive terminal of the DC bus of the three-phase H-bridge converter.

[0009] Preferably, the step S4 specifically includes: When the rotor is in the first sector, the phase currents of the A-phase winding, the B-phase winding, and the C-phase winding are respectively: i a =|i LEM1 | / 2, i b =0、i c =-|i LEM1 | / 2; When the rotor is in the second sector, the phase currents of the A-phase winding, the B-phase winding, and the C-phase winding are: i a =-|i LEM1 | / 2, i b =|iLEM1 | / 2, i c =0; When the rotor is in the third sector, the phase currents of the A-phase winding, the B-phase winding, and the C-phase winding are: i a =0、i b =-|i LEM1 | / 2, i c =|i LEM1 | / 2.

[0010] Preferably, in step S3, a position sensor is used to obtain the motor rotor position angle in real time.

[0011] Compared with the closest prior art, the technical solution of the embodiment of the present application has the following beneficial effects: The phase current reconstruction method described in this application samples bus current and, in combination with the operating principle of a doubly salient motor, reconstructs three-phase current information in real time by analyzing the relationship between phase current and bus current in different current loops to achieve closed-loop current control of the system. Compared to traditional open-winding doubly salient motor drive systems that require three phase current sensors, this application requires only one current sensor, which not only reduces system costs but also has significant significance for improving the reliability of the motor drive system. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings and descriptions that constitute part of this application are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. Among them: Figure 1 This is a schematic diagram of the placement of the current sensor for a conventional open-winding doubly salient motor; Figure 2 The inductance curve of the open-winding doubly salient motor and the turn-on logic of the H-bridge converter; Figure 3 This is a schematic diagram of the placement of the current sensor for the open-winding double-salient-pole motor in this application; Figure 4 is the current loop diagram when the switch tube in the first sector is turned on; Figure 5 This is the current loop diagram when the switch tube in the first sector is turned off; Figure 6 This is a flow chart of the phase current reconstruction method of this application; Figure 7 This is a block diagram of the motor system structure using the phase current reconstruction method of this application.

[0013] Description of reference numerals: 1. Phase current sensor; 2. Current sensor. DETAILED DESCRIPTION

[0014] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments. Each example is provided by way of explanation of the present application and does not limit the present application. In fact, it will be clear to those skilled in the art that modifications and variations can be made in the present application without departing from the scope or spirit of the present application. For example, a feature shown or described as part of one embodiment can be used in another embodiment to produce yet another embodiment. Therefore, it is expected that the present application includes such modifications and variations within the scope of the appended claims and their equivalents.

[0015] In the following description, the terms "first / second / third" involved are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It is understandable that "first / second / third" can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art in the art of the present disclosure. The terms used herein are only for the purpose of describing the embodiments of the present disclosure and are not intended to limit the present disclosure.

[0017] In the description of this application, the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and do not require that this application must be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on this application. The terms "connected", "connected", and "set" used in this application should be understood in a broad sense. For example, they can be fixed connections or detachable connections; they can be directly connected or indirectly connected through intermediate components; they can be wired electrical connections, radio connections, or wireless communication signal connections. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0018] The following is a combination of Figure 1-7 A phase current reconstruction method for an open-winding doubly salient motor of the present application is further described in detail.

[0019] A method for reconstructing phase current of an open-winding doubly salient motor, comprising: Step S1: Remove the three phase current sensors 1 in the three-phase H-bridge converter, set a current sensor 2 on the DC bus of the three-phase H-bridge converter and set its measured value as i LEM1 ; Step S2: Adjust the chopping strategy of the drive system to PWM-PWM mode; Step S3: acquiring the motor rotor position angle in real time, and determining the sector of the rotor according to the rotor position angle, wherein the rotor position angle interval of 0° to 120° is the first sector, the rotor position angle interval of 120° to 240° is the second sector, and the rotor position angle interval of 240° to 360° is the third sector; Step S4: Combined with the working principle of the open-winding doubly salient motor, the phase currents in different current loops in different sectors and i LEM1 The phase current is reconstructed based on the relationship between

[0020] In a specific embodiment of the present application, the open-winding doubly salient motor is specifically an electrically excited doubly salient motor (DSEM), which adopts a three-phase H-bridge converter as the inverter topology; the three-phase H-bridge converter includes a DC power supply U dc , filter capacitor C dc And three H-bridge converters; the upper bridge arms of the three H-bridge converters are connected to the positive end of the DC bus, and the lower bridge arms are connected to the negative end of the DC bus; the three H-bridge converters are respectively connected to the motor A-phase winding, B-phase winding and C-phase winding, among which the upper bridge arm of the H-bridge converter where the A-phase winding is located is arranged with switch tubes T on the left and right A1 , switch tube T A2 , the switch tubes T are arranged on the left and right sides of the lower bridge arm A3 , switch tube T A4 , switch tube T A1 , switch tube T A2 , switch tube T A3 , switch tube T A4 Connect reverse diode D in parallel at both ends A1 , diode D A2 , diode D A3 , diode D A4 The switch tubes T are arranged on the left and right sides of the upper bridge arm of the H-bridge converter where the B phase winding is located. B1 , switch tube T B2 , the switch tubes T are arranged on the left and right sides of the lower bridge arm B3 , switch tube T B4 , switch tube T B1 , switch tube T B2 , switch tube T B3 , switch tube T B4 Connect reverse diode D in parallel at both ends B1 , diode D B2 , diode D B3 , diode D B4 The switch tubes T are arranged on the left and right sides of the upper bridge arm of the H-bridge converter where the C phase winding is located. C1 , switch tube T C2 , the switch tubes T are arranged on the left and right sides of the lower bridge armC3 , switch tube T C4 , switch tube T C1 , switch tube T C2 , switch tube T C3 , switch tube T C4 Connect reverse diode D in parallel at both ends C1 , diode D C2 , diode D C3 , diode D C4 .

[0021] Based on the conduction logic of the H-bridge converter, taking the A-phase winding as an example, the switch tube T on the diagonal of the H-bridge converter A1 With the switch tube T A4 At the same time, the switch tube T on the other diagonal line of the H-bridge converter participates in the control work. A2 With the switch tube T A3 On this basis, the PWM-PWM chopping strategy (upper switch tube and lower switch tube are chopped at the same time) is adopted, that is, the switch tube T that participates in the control work at the same time A1 , switch tube T A4 Or switch tube T A2 , switch tube T A3 By turning on and off simultaneously at a certain frequency, the phase current can be kept flowing through the current sensor 2 installed on the DC bus, and the phase current information can be obtained in real time based on the current sensor 2.

[0022] Step S3 further includes: When the rotor is in the first sector, the H-bridge converter switch tube T where the A-phase winding is located A1 , switch tube T A4 Participate in the control work, the H-bridge converter switch tube T where the C phase winding is located C2 , switch tube T C3 Participate in the control work, the H-bridge converter where the B-phase winding is located does not work; When the rotor is in the second sector, the H-bridge converter switch tube T where the A-phase winding is located A2 , switch tube T A3 Participate in the control work, the H-bridge converter switch tube T where the B phase winding is located B1 , switch tube T B4 Participate in the control work, the H-bridge converter where the C-phase winding is located does not work; When the rotor is in the third sector, the H-bridge converter switch tube T where the B-phase winding is located B2 , switch tube T B3 Participate in the control work, the H-bridge converter switch tube T where the C phase winding is located C1 , switch tube T C4 Participates in the control work, and the H-bridge converter where the A-phase winding is located does not work.

[0023] In a specific embodiment of the present application, the rotor position angle is the electrical angle between the rotor N-stage and the A-phase winding, that is, when the rotor position angle is 0°, the rotor N-stage coincides with the A-phase winding; Figure 2 The inductor curve of the open-winding doubly salient motor and the conduction logic diagram of the H-bridge converter are shown in Figure 1, where θ is the rotor position angle of the motor, L af is the mutual inductance between the A-phase winding and the excitation winding, L bf is the mutual inductance between the B-phase winding and the excitation winding, L cf is the mutual inductance between the C-phase winding and the excitation winding.

[0024] Specifically, the positive direction of the current is as follows Figure 1 The direction indicated by the arrow in the middle is the positive direction of current from left to right. According to the principle of "positive current flows in the rising area of ​​inductance and negative current flows in the falling area of ​​inductance": When the rotor is in the first sector, the H-bridge converter switch tube T where the A-phase winding is located A1 , switch tube T A4 The H-bridge converter switch tube T where the C phase winding is located C2 , switch tube T C3 Under the signal control of the drive system, the two working states of on and off are continuously switched simultaneously, and the H-bridge converter where the B-phase winding is located does not work; When the rotor is in the second sector, the H-bridge converter switch tube T where the A-phase winding is located A2 , switch tube T A3 The H-bridge converter switch tube T where the B phase winding is located B1 , switch tube T B4 Under the signal control of the drive system, the two working states of on and off are continuously switched simultaneously, and the H-bridge converter where the C-phase winding is located does not work; When the rotor is in the third sector, the H-bridge converter switch tube T where the B-phase winding is located B2 , switch tube T B3 The H-bridge converter switch tube T where the C phase winding is located C1 , switch tube T C4 Under the signal control of the drive system, the two working states of on and off are continuously switched simultaneously, and the H-bridge converter where the A-phase winding is located does not work.

[0025] Combined with attachment Figure 3 As shown, in step S1 , the current sensor 2 is installed at the positive terminal of the DC bus of the three-phase H-bridge converter.

[0026] In a specific embodiment of the present application, the current sensor 2 is a CSDC series switch type current sensor.

[0027] In other embodiments of the present application, the current sensor 2 is installed at the negative terminal of the DC bus of the three-phase H-bridge converter.

[0028] Step S4 specifically includes: When the rotor is in the first sector, the phase currents of the A-phase winding, the B-phase winding, and the C-phase winding are respectively: i a =|i LEM1 | / 2, i b =0、i c =-|i LEM1 | / 2; When the rotor is in the second sector, the phase currents of the A-phase winding, the B-phase winding, and the C-phase winding are: i a =-|i LEM1 | / 2, i b =|i LEM1 | / 2, i c =0; When the rotor is in the third sector, the phase currents of the A-phase winding, the B-phase winding, and the C-phase winding are: i a =0、i b =-|i LEM1 | / 2, i c =|i LEM1 | / 2.

[0029] In a specific embodiment of the present application, When the rotor is in the first sector, the switch tube T A1 、T A4 、T C2 and T C3 Participate in control work; when the switch tube T A1 、T A4 、T C2 and T C3 When both are turned on, the current loop is as follows Figure 4 As shown, there are two circuits: U dc →T A1 →A→T A4 , U dc →T C2 →C→T C3 , combined with Kirchhoff's current law, we can get i LEM1 =i a -i c 、i b =0; when the switch tube T A1 、T A4 、T C2 and T C3 When the windings of phase A and phase C are turned off at the same time, the inductive freewheeling current occurs, and the freewheeling current loop is as follows: Figure 5 As shown, there are two circuits: U dc →DA3 →A→D A2 , U dc →D C4 →C→D C1 , combined with Kirchhoff's current law, we can get -i LEM1 =-i a +i c 、i b =0; In addition, since the A-phase winding and the C-phase winding are in parallel operation and have the same load, i a= -i c , and then i a =|i LEM1 | / 2, i b =0、i c =-|i LEM1 | / 2; When the rotor is in the second sector, the switch tube T A2 、T A3 、T B1 and T B4 Participate in control work; when the switch tube T A2 、T A3 、T B1 and T B4 When conducting at the same time, there are two circuits: U dc →T A2 →A→T A3 , U dc →T B1 →C→T B4 , combined with Kirchhoff's current law, we can get i LEM1 =-i a +i b 、i c =0; when the switch tube T A2 、T A3 、T B1 and T B4 When the windings are turned off at the same time, the A-phase winding and the B-phase winding generate inductive freewheeling, which contains two circuits: U dc →D A4 →A→D A1 , U dc →D B3 →C→D B2 , combined with Kirchhoff's current law, we can get -i LEM1 =i a -i b 、i c =0; In addition, since the A-phase winding and the B-phase winding are in parallel operation and have the same load, -i a= i b , and then i a =-|i LEM1 | / 2, i b=|i LEM1 | / 2, i c =0; When the rotor is in the third sector, the switch tube T B2 、T B3 、T C1 and T C4 Participate in control work; when the switch tube T B2 、T B3 、T C1 and T C4 When conducting at the same time, there are two circuits: U dc →T B2 →A→T B3 , U dc →T C1 →C→T C4 , combined with Kirchhoff's current law, we can get i LEM1 =-i b +i c 、i a =0; when the switch tube T B2 、T B3 、T C1 and T C4 When the windings are turned off at the same time, the B-phase winding and the C-phase winding generate inductive freewheeling, which includes two circuits: U dc →D B4 →A→D B1 , U dc →D C3 →C→D C2 , combined with Kirchhoff's current law, we can get -i LEM1 =i b -i c 、i a =0; In addition, since the B-phase winding and the C-phase winding are in parallel operation and have the same load, -i b= i c , and then i a =0、i b =-|i LEM1 | / 2, i c =|i LEM1 | / 2.

[0030] In step S3, a position sensor is used to obtain the motor rotor position angle in real time.

[0031] Figure 7 The block diagram of the open-winding double-salient-pole motor system using the phase current reconstruction method described in this application, where n * and i p * They are the speed given value and the phase current given value respectively; the working principle is: the speed given value n *The speed controller outputs the current given value i, which is subtracted from the speed feedback value n. p * ; Then, the current is given to value i p * The phase current reconstruction method described in this application is used to make a difference, and the PWM signal is output through the current controller; it can be found that the phase current reconstruction method described in this application only uses the current measurement value i LEM1 , and combined with the motor rotor position information, the three-phase current can be reconstructed.

[0032] The foregoing description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are readily apparent to those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for reconstructing phase current of an open-winding doubly salient motor, characterized in that: include: Step S1: Remove the three phase current sensors in the three-phase H-bridge converter, set a current sensor on the DC bus of the three-phase H-bridge converter and set its measured value as i LEM1 ; Step S2: Adjust the chopping strategy of the drive system to PWM-PWM mode; Step S3: acquiring the motor rotor position angle in real time, and determining the sector of the rotor according to the rotor position angle, wherein the rotor position angle interval of 0° to 120° is the first sector, the rotor position angle interval of 120° to 240° is the second sector, and the rotor position angle interval of 240° to 360° is the third sector; Step S4: Combined with the working principle of the open-winding doubly salient motor, the phase currents in different current loops in different sectors and i LEM1 The phase current is reconstructed based on the relationship between 2. A method for reconstructing phase current of an open-winding doubly salient motor according to claim 1, characterized in that: The step S3 further comprises: When the rotor is in the first sector, the H-bridge converter switch tube T where the A-phase winding is located A1 , switch tube T A4 Participate in the control work, the H-bridge converter switch tube T where the C phase winding is located C2 , switch tube T C3 Participate in the control work, the H-bridge converter where the B-phase winding is located does not work; When the rotor is in the second sector, the H-bridge converter switch tube T where the A-phase winding is located A2 , switch tube T A3 Participate in the control work, the H-bridge converter switch tube T where the B phase winding is located B1 , switch tube T B4 Participate in the control work, the H-bridge converter where the C-phase winding is located does not work; When the rotor is in the third sector, the H-bridge converter switch tube T where the B-phase winding is located B2 , switch tube T B3 Participate in the control work, the H-bridge converter switch tube T where the C phase winding is located C1 , switch tube T C4 Participates in the control work, and the H-bridge converter where the A-phase winding is located does not work.

3. The method for reconstructing phase current of an open-winding doubly salient motor according to claim 2, wherein: In step S1 , the current sensor is installed at the positive terminal of the DC bus of the three-phase H-bridge converter.

4. The method for reconstructing phase current of an open-winding doubly salient motor according to claim 3, wherein: The step S4 specifically includes: When the rotor is in the first sector, the phase currents of the A-phase winding, the B-phase winding, and the C-phase winding are respectively: i a =|i LEM1 | / 2, i b =0、i c =-|i LEM1 | / 2; When the rotor is in the second sector, the phase currents of the A-phase winding, the B-phase winding, and the C-phase winding are: i a =-|i LEM1 | / 2, i b =|i LEM1 | / 2, i c =0; When the rotor is in the third sector, the phase currents of the A-phase winding, the B-phase winding, and the C-phase winding are: i a =0、i b =-|i LEM1 | / 2, i c =|i LEM1 | / 2.

5. A method for reconstructing phase current of an open-winding doubly salient motor according to any one of claims 1 to 4, characterized in that: In step S3, a position sensor is used to obtain the motor rotor position angle in real time.

Images