A control method and system for switched reluctance motor based on non-phase-shifted current reconstruction

Abstract

The application discloses a kind of based on the control method and system of current reconstruction of non-phase shift switch reluctance motor, belong to motor drive control field, including: open-winding motor driver, current detection module, position detection module, current controller, pulse width modulator, voltage modulation module, unmeasurable area compensation module, the number of current sensor in open-winding motor driver is only one.The application plans the sampling time of current sensor, and the conduction time of each bridge arm of two converters in open-winding motor driver is corrected on-line, on the basis of not phase-shifting switch tube driving signal, guaranteeing the center symmetry of the driving signal of all switch tubes, simultaneously realizes the detection of rotating current component and zero sequence current component of switch reluctance motor driven by open-winding motor driver, avoids the unmeasurable area of current sensor, and improves the operation stability of switch reluctance motor system.

Description

Technical Field

[0001] This invention belongs to the field of motor drive control, and more specifically, relates to a control method and system for a switched reluctance motor based on phase-shift-free current reconfiguration. Background Technology

[0002] With the rapid development of industrial production and the urgent need for environmental protection, electrical energy has been widely used due to its ease of transmission, flexible control, and low environmental pollution. Under this premise, the electric motor, as the core component for realizing electromechanical energy conversion, has received widespread attention from experts and scholars. For electric motors, the driver and controller determine the performance and reliability of motor operation, holding a crucial position.

[0003] Traditional motor systems typically employ a star-connected winding structure, with one end of each phase winding connected to the output of the motor driver, and the other ends connected together to form the winding neutral point. Limited by the voltage withstand capability, heat dissipation, and power rating of power devices, this traditional motor system struggles to meet the demands of high power ratings and high reliability. Therefore, switched reluctance motors driven by open-winding motor drivers have emerged. Switched reluctance motors do not have a winding neutral point; the two ends of each phase winding are connected to the outputs of two converters in the open-winding motor driver, and are powered by a sinusoidal current with DC bias. This structure significantly improves DC bus voltage utilization and control freedom, ensuring the performance and reliability of the motor system.

[0004] High-precision current detection is crucial for ensuring the accuracy of motor control. However, for switched reluctance motors, which lack a winding neutral point, all three-phase currents contain zero-sequence components, requiring at least three current sensors. This increased number of current sensors significantly increases the cost and size of the motor system. Furthermore, the use of more sensors raises the potential risk of system failure and reduces system reliability. To address this issue, existing research proposes a single-sensor current reconstruction method for open-winding motor drivers based on phase shifting of the switching signals. However, this method significantly increases the control complexity of the controller due to the complex phase shifting and alignment operations required for the switching signals of the open-winding motor driver. Additionally, the phase shifting of the switching signals causes all switching signals to no longer be centrally symmetrically distributed in each switching cycle, leading to non-ideal switching harmonics and deteriorating the motor's output characteristics. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a control method and system for switched reluctance motors based on phase-shift-free current reconstruction. This system addresses the issues of high cost and low reliability caused by the large number of current sensors in existing switched reluctance motor systems, as well as the high control complexity and non-ideal switching harmonics caused by phase shift of the switching signals in existing single-current-sensor sampling systems.

[0006] To achieve the above objectives, the present invention provides a control method for a switched reluctance motor based on phase-shift-free current reconstruction.

[0007] An open-winding motor driver includes a converter 1, a converter 2, a current sensor, and a position sensor, used to provide current to a switched reluctance motor. The converter 2 is directly connected between the positive and negative terminals of a DC power supply. The converter 1 and the converter 2 are connected by a positive DC bus and a negative DC bus. The current sensor is installed on the negative DC bus between the converter 1 and the converter 2. The current flowing through the current sensor is only affected by the conduction state of the converter 1.

[0008] The control method for switched reluctance motors includes the following steps:

[0009] S1. Based on the switching signal of converter 1 in the open-winding motor driver, determine the three sampling points t of the current sensor in each switching cycle. s1 t s2 t s3 Specifically, the first sampling point t of the current sensor in each switching cycle s1 The second sampling point t is located at the beginning of the switching cycle of converter 1. s2 Located at the starting point of the first effective vector of transformer 1, the third sampling point t s3 Located at the starting point of the second effective vector of converter 1; three sampling points t within each switching cycle. s1 t s2 t s3 The current sensor is sampled three times to obtain three corresponding current sample values ​​i. s1 i s2 i s3 ;

[0010] S2. Based on the reference voltage u of converter 1 α1 and u β1 The operating sector of converter 1 is determined. Within different sectors, the three-phase current calculation module uses different calculation methods, combined with the first current sampling value i. s1 Second current sampling value i s2 and the third current sampling value i s3 Calculate the three-phase current i of the switched reluctance motor. a i b and i c Utilizing the three-phase current i of the switched reluctance motor a i b and i c Based on the rotational coordinate transformation, the current component i in the synchronous rotating coordinate system is calculated. d iq and i0; specifically, the calculation methods for three-phase currents in different sectors are as follows:

[0011] In Sector I, i a =i s1 -i s2 ,i b =i s2 -i s3 ,i c =i s3 ;

[0012] In Sector II, i a =i s2 -i s3 ,i b =i s1 -i s2 ,i c =i s3 ;

[0013] In Sector III, i a =i s3 ,i b =i s1 -i s2 ,i c =i s2 -i s3 ;

[0014] In Sector IV, i a =i s3 ,i b =i s2 -i s3 ,i c =i s1 -i s2 ;

[0015] In Sector V, i a =i s2 -i s3 ,i b =i s3 ,i c =i s1 -i s2 ;

[0016] In Sector VI, i a =i s1 -i s2 ,i b =i s3 ,i c =i s2 -i s3 .

[0017] S3. According to the reference value i of the effective value of the phase current of the switched reluctance motorrms * Calculate the current reference value i in the synchronous rotating coordinate system. d * i q * i0 * , and current component i d i q By subtracting i0 from i0 and using the vector proportional-integral algorithm, the voltage reference value u of the switched reluctance motor in the synchronous rotating coordinate system is calculated. d u q u0;

[0018] S4. Based on the rotor electrical angle θ of the switched reluctance motor. e , for u d u q By performing a coordinate transformation on u0, the rotating voltage components u of the two converters are obtained. αβ12 and common-mode voltage component CMV 12 Based on the rotating voltage components u of the two converters respectively αβ12 and common-mode voltage component CMV 12 Calculate the conduction time T of the three bridge arms in converter 1 during one switching cycle. 11 T 21 and T 31 The conduction time T of the three bridge arms in converter 2 within one switching cycle 12 T 22 and T 32 ;

[0019] S5. Correct the conduction time of the two converters so that the time for three current samplings within each switching cycle meets the minimum sampling time T. min The requirements are as follows: calculate the duty cycle of each bridge arm, and then obtain the switching signal, which is input to the open winding motor driver to realize the control of the motor.

[0020] Furthermore, the correction of the conduction time of the two converters in S5 includes the following steps:

[0021] S51. Based on the conduction time T of the first bridge arm in converter 1 11 Second bridge arm conduction time T 21 The conduction time T of the third bridge arm 31 Calculate the duration of three current sensor samplings within one switching cycle, where T s Switching cycle for open-winding motor driver:

[0022] Duration T of the first current sensor sampling s1 =(T s -T 11 ) / 2;

[0023] The duration T of the second current sensor sampling s2 =(T 11 -T 21 ) / 2;

[0024] The duration T of the third current sensor sampling s3 =T 21 ;

[0025] S52. Within each sector of converter 1, determine the duration T of the third current sensor sampling. s3 Is it greater than the minimum sampling time T of the current sensor? min If this condition is not met, then when converter 1 is in sectors I, III, or V, the bridge arm conduction time of converter 1 and converter 2 is corrected as follows: T ’ 21 =T min ;T ’ 12 =T 12 +(T ’ 21 -T 21 When converter 1 is in sectors II, IV, and VI, the conduction time of the bridge arms of converter 1 and converter 2 is corrected as follows: T ’ 21 =T min ;T ’ 32 =T 32 +(T ’ 21 -T 21 ); where the superscript “'” indicates the corrected bridge arm conduction time;

[0026] S53. Within each sector of converter 1, determine the duration T of the second current sensor sampling. s2 Is it greater than the minimum sampling time T of the current sensor? min If this condition is not met, then when converter 1 is in sectors I, III, or V, the bridge arm conduction time of converter 1 and converter 2 is corrected as follows: T ’ 11 =T ’ 21 +2*T min ;T ’ 32 =T 32 +(T ’ 11 -T 11When converter 1 is in sectors II, IV, and VI, the conduction time of the bridge arms of converter 1 and converter 2 is corrected as follows: T ’ 11 =T ’ 21 +2*T min ;T ’ 22 =T 22 +(T ’ 11 -T 11 ); where the superscript “'” indicates the corrected bridge arm conduction time.

[0027] In another aspect, the present invention proposes a current control system for a switched reluctance motor based on phase-shift-free current reconstruction, comprising: an open-winding motor driver, a current detection module, a position detection module, a current controller, a pulse width modulator, a voltage modulation module, and an unmeasurable region compensation module.

[0028] The current detection module is used to determine three sampling points t of the current sensor in each switching cycle based on the switching signal of converter 1 in the open-winding motor driver. s1 t s2 t s3 First sampling point t s1 The second sampling point t is located at the beginning of the switching cycle of converter 1. s2 Located at the starting point of the first effective vector of transformer 1, the third sampling point t s3 The starting point of the second effective vector located at converter 1; at the three sampling points t s1 t s2 t s3 The current sensor is sampled three times to obtain three corresponding current sample values ​​i. s1 i s2 i s3 According to the reference voltage u of converter 1 α1 and u β1 Determine the operating sector of converter 1, and within different sectors, combine i s1 i s2 i s3 Calculate the three-phase current i of the switched reluctance motor. a i b and i c Perform a rotational coordinate transformation to obtain the current component i in the synchronously rotating coordinate system. d i q and i0;

[0029] The position detection module is used to measure the rotor mechanical position θ. mBased on the initial position and number of pole pairs of the switched reluctance motor, the rotor electrical angle θ is calculated. e ;

[0030] The current controller is used to control the current of the switched reluctance motor in a synchronous rotating coordinate system, so that the actual current value follows its reference value. First, the current distribution module determines the effective value of the phase current of the switched reluctance motor based on the reference value i. rms * The reference current value i in the synchronous rotating coordinate system is calculated using the following method. d * i q * i0 * :

[0031] i d * =0; i q * =i rms * ;

[0032] Furthermore, the harmonic current controller uses the current reference value i in the synchronous rotating coordinate system. d * i q * i0 * and actual value i d i q Using the vector proportional-integral algorithm, the voltage reference value u of the switched reluctance motor in the synchronous rotating coordinate system is calculated. d u q u0 ensures that the actual current value follows its reference value.

[0033] The pulse width modulator is used to adjust the rotor electrical angle θ of the switched reluctance motor. e Calculate the voltage reference value u of the switched reluctance motor in the synchronous rotating coordinate system. d u q u0, obtain the switching signal, and input it to the open winding motor driver.

[0034] First, using a rotating coordinate transformation, based on the voltage reference value u in a synchronously rotating coordinate system... d u q The rotating voltage components u of the two converters are calculated from u0. αβ12 and common-mode voltage component CMV 12 The output voltages of the two converters should have a 120° phase difference to avoid the generation of non-ideal zero-sequence harmonic voltages;

[0035] Secondly, the voltage modulation module modulates the voltage based on the rotating voltage component u of converter 1. αβ1 Calculate the conduction time T of the three bridge arms in converter 1 during one switching cycle, based on the common-mode voltage component CMV1. 11 T 21 and T 31 T 11 T is the conduction time of the first bridge arm to conduct. 21 T is the conduction time of the second conducting bridge arm. 31 This refers to the conduction time of the last bridge arm to be turned on; simultaneously, based on the rotating voltage component u of converter 2... αβ2 Calculate the conduction time T of the three bridge arms in converter 2 within one switching cycle, based on the common-mode voltage component CMV2. 12 T 22 and T 32 T 12 T is the conduction time of the first bridge arm to conduct. 22 T is the conduction time of the second conducting bridge arm. 32 This refers to the conduction time of the last bridge arm to be activated.

[0036] Furthermore, the unmeasurable region compensation module is used to correct the conduction time of the two converters according to the following steps, so that the time for three current samplings within each switching cycle meets the minimum sampling time T. min Requirements:

[0037] S51. Based on the conduction time T of the first bridge arm in converter 1 11 Second bridge arm conduction time T 21 The conduction time T of the third bridge arm 31 Calculate the duration of three current sensor samplings within one switching cycle, where T s Switching cycle for open-winding motor driver:

[0038] Duration T of the first current sensor sampling s1 =(T s -T 11 ) / 2;

[0039] The duration T of the second current sensor sampling s2 =(T 11 -T 21 ) / 2;

[0040] The duration T of the third current sensor sampling s3 =T 21 ;

[0041] S52. Within each sector of converter 1, determine the duration T of the third current sensor sampling. s3Is it greater than the minimum sampling time T of the current sensor? min If this condition is not met, then when converter 1 is in sectors I, III, or V, the bridge arm conduction time of converter 1 and converter 2 is corrected as follows: T ’ 21 =T min ;T ’ 12 =T 12 +(T ’ 21 -T 21 When converter 1 is in sectors II, IV, and VI, the conduction time of the bridge arms of converter 1 and converter 2 is corrected as follows: T ’ 21 =T min ;T ’ 32 =T 32 +(T ’ 21 -T 21 ); where the superscript “'” indicates the corrected bridge arm conduction time;

[0042] S53. Within each sector of converter 1, determine the duration T of the second current sensor sampling. s2 Is it greater than the minimum sampling time T of the current sensor? min If this condition is not met, then when converter 1 is in sectors I, III, or V, the bridge arm conduction time of converter 1 and converter 2 is corrected as follows: T ’ 11 =T ’ 21 +2*T min ;T ’ 32 =T 32 +(T ’ 11 -T 11 When converter 1 is in sectors II, IV, and VI, the conduction time of the bridge arms of converter 1 and converter 2 is corrected as follows: T ’ 11 =T ’ 21 +2*T min ;T ’ 22 =T 22 +(T ’ 11 -T 11 ); where the superscript "'" indicates the corrected bridge arm conduction time; minimum sampling time T minThe sum of the dead time, analog-to-digital signal conversion time, current regulation time, and signal transmission delay of the open-winding motor driver; after compensation for the unmeasurable region, the switching signal remains centrally symmetrical, and no phase shift is required to achieve compensation for the unmeasurable region.

[0043] Furthermore, using the duty cycle calculation module, the duty cycle of each bridge arm of converter 1 and converter 2 is calculated based on the conduction time of each bridge arm, thereby obtaining the switching signal, which is then input to the open winding motor driver to control the motor.

[0044] Compared with existing technologies, the technical solution conceived in this invention, by setting the installation position of the current sensor, setting the current sampling point, proposing current calculation methods in different sectors, and proposing compensation methods for unmeasurable areas, enables current detection of switched reluctance motors using only a single current sensor. It also ensures the central symmetry of the switching signal, avoiding the complex phase shift of the switching signal and the resulting non-ideal switching harmonics in existing technologies, thus significantly improving the operational reliability of the switched reluctance motor system. The technical solution proposed in this invention is not only applicable to switched reluctance motors but also to any type of motor driven by an open-winding motor driver. Attached Figure Description

[0045] Figure 1 This is a control block diagram of a switched reluctance motor control system based on phase-shift current reconfiguration according to an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram showing the locations of three current sampling points in different sectors according to an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of the sector distribution of converter 1 in an embodiment of the present invention;

[0048] Figure 4 This is a flowchart of the unmeasurable region compensation module in an embodiment of the present invention;

[0049] Figure 5 This is a schematic diagram of an open-winding motor driver according to an embodiment of the present invention. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0051] like Figure 1As shown, this invention proposes a current control system for a switched reluctance motor based on phase-shift-free current reconstruction, comprising: an open-winding motor driver, a current detection module, a position detection module, a current controller, a pulse width modulator, a voltage modulation module, and an unmeasurable region compensation module.

[0052] The current detection module is used to determine three sampling points t of the current sensor in each switching cycle based on the switching signal of converter 1 in the open-winding motor driver. s1 t s2 t s3 First sampling point t s1 The second sampling point t is located at the beginning of the switching cycle of converter 1. s2 Located at the starting point of the first effective vector of transformer 1, the third sampling point t s3 The starting point of the second effective vector located at converter 1; at the three sampling points t s1 t s2 t s3 The current sensor is sampled three times to obtain three corresponding current sample values ​​i. s1 i s2 i s3 According to the reference voltage u of converter 1 α1 and u β1 Determine the operating sector of converter 1, and within different sectors, combine i s1 i s2 i s3 Calculate the three-phase current i of the switched reluctance motor. a i b and i c Perform a rotational coordinate transformation to obtain the current component i in the synchronously rotating coordinate system. d i q and i0;

[0053] The position detection module is used to measure the rotor mechanical position θ. m Based on the initial position and number of pole pairs of the switched reluctance motor, the rotor electrical angle θ is calculated. e ;

[0054] The current controller is used to control the current of the switched reluctance motor in a synchronous rotating coordinate system, so that the actual current value follows its reference value. First, the current distribution module determines the effective value of the phase current of the switched reluctance motor based on the reference value i. rms * The reference current value i in the synchronous rotating coordinate system is calculated using the following method. d * i q * i0 * :id * =0; i q * =i rms * ; The harmonic current controller is based on the current reference value i in the synchronous rotating coordinate system. d * i q * i0 * and actual value i d i q Using the vector proportional-integral algorithm, the voltage reference value u of the switched reluctance motor in the synchronous rotating coordinate system is calculated. d u q u0 ensures that the actual current value follows its reference value.

[0055] The pulse width modulator is used to adjust the rotor electrical angle θ of the switched reluctance motor. e Calculate the voltage reference value u of the switched reluctance motor in the synchronous rotating coordinate system. d u q The switching signal, u0, is obtained and input to the open-winding motor driver. Using rotating coordinate transformation, the voltage reference value u in the synchronous rotating coordinate system is used... d u q The rotating voltage components u of the two converters are calculated from u0. αβ12 and common-mode voltage component CMV 12 The output voltages of the two converters should have a 120° phase difference to avoid the generation of non-ideal zero-sequence harmonic voltages.

[0056] The voltage modulation module is used to adjust the voltage based on the rotating voltage component u of converter 1. αβ1 Calculate the conduction time T of the three bridge arms in converter 1 during one switching cycle, based on the common-mode voltage component CMV1. 11 T 21 and T 31 T 11 T is the conduction time of the first bridge arm to conduct. 21 T is the conduction time of the second conducting bridge arm. 31 This refers to the conduction time of the last bridge arm to be turned on; simultaneously, based on the rotating voltage component u of converter 2... αβ2 Calculate the conduction time T of the three bridge arms in converter 2 within one switching cycle, based on the common-mode voltage component CMV2. 12 T 22 and T 32 T 12 T is the conduction time of the first bridge arm to conduct. 22T is the conduction time of the second conducting bridge arm. 32 This refers to the conduction time of the last bridge arm to be activated.

[0057] The unmeasurable region compensation module is used to correct the conduction time of the two converters according to the following steps, so that the time for three current samplings within each switching cycle meets the minimum sampling time T. min Requirements:

[0058] S51. Based on the conduction time T of the first bridge arm in converter 1 11 Second bridge arm conduction time T 21 The conduction time T of the third bridge arm 31 Calculate the duration of three current sensor samplings within one switching cycle, where T s Switching cycle for open-winding motor driver:

[0059] Duration T of the first current sensor sampling s1 =(T s -T 11 ) / 2;

[0060] The duration T of the second current sensor sampling s2 =(T 11 -T 21 ) / 2;

[0061] The duration T of the third current sensor sampling s3 =T 21 ;

[0062] S52. Within each sector of converter 1, determine the duration T of the third current sensor sampling. s3 Is it greater than the minimum sampling time T of the current sensor? min If this condition is not met, then when converter 1 is in sectors I, III, or V, the bridge arm conduction time of converter 1 and converter 2 is corrected as follows: T ’ 21 =T min ;T ’ 12 =T 12 +(T ’ 21 -T 21 When converter 1 is in sectors II, IV, and VI, the conduction time of the bridge arms of converter 1 and converter 2 is corrected as follows: T ’ 21 =T min ;T ’ 32 =T 32 +(T ’21 -T 21 ); where the superscript “'” indicates the corrected bridge arm conduction time;

[0063] S53. Within each sector of converter 1, determine the duration T of the second current sensor sampling. s2 Is it greater than the minimum sampling time T of the current sensor? min If this condition is not met, then when converter 1 is in sectors I, III, or V, the bridge arm conduction time of converter 1 and converter 2 is corrected as follows: T ’ 11 =T ’ 21 +2*T min ;T ’ 32 =T 32 +(T ’ 11 -T 11 When converter 1 is in sectors II, IV, and VI, the conduction time of the bridge arms of converter 1 and converter 2 is corrected as follows: T ’ 11 =T ’ 21 +2*T min ;T ’ 22 =T 22 +(T ’ 11 -T 11 ); where the superscript "'" indicates the corrected bridge arm conduction time; minimum sampling time T min The sum of the dead time, analog-to-digital signal conversion time, current regulation time, and signal transmission delay of the open-winding motor driver; after compensation for the unmeasurable region, the switching signal remains centrally symmetrical, and no phase shift is required to achieve compensation for the unmeasurable region.

[0064] The duty cycle calculation module is used to calculate the duty cycle of each bridge arm by taking the conduction time of each bridge arm of converter 1 and converter 2, and then obtain the switching signal, which is input to the open winding motor driver to realize the control of the motor.

[0065] This invention also proposes a control method for a switched reluctance motor based on phase-shift-free current reconstruction, comprising the following steps:

[0066] S1. Based on the switching signal of converter 1 in the open-winding motor driver, determine the three sampling points t of the current sensor in each switching cycle. s1 t s2 t s3Specifically, the first sampling point t of the current sensor in each switching cycle s1 The second sampling point t is located at the beginning of the switching cycle of converter 1. s2 Located at the starting point of the first effective vector of transformer 1, the third sampling point t s3 Located at the starting point of the second effective vector of converter 1, three sampling points t are located in different sectors. s1 t s2 t s3 Position such as Figure 2 As shown; three sampling points t within each switching cycle s1 t s2 t s3 The current sensor is sampled three times to obtain three corresponding current sample values ​​i. s1 i s2 i s3 ;

[0067] S2. Based on the reference voltage u of converter 1 α1 and u β1 Determine the operating sector of converter 1. The sector distribution of converter 1 is as follows: Figure 3 As shown. Within different sectors, the three-phase current calculation module utilizes different calculation methods, based on three corresponding current sampling values ​​i. s1 i s2 i s3 Calculate the three-phase current i of the switched reluctance motor. a i b and i c Utilizing the three-phase current i of the switched reluctance motor a i b and i c Based on the rotational coordinate transformation, the current component i in the synchronous rotating coordinate system is calculated. d i q And i0; specifically, the three-phase current of converter 1 in different sectors is calculated as follows:

[0068] In sector I, i a =i s1 -i s2 i b =i s2 -i s3 i c =i s3 ,

[0069] In sector II, i a =i s2 -i s3 i b =i s1 -is2 i c =i s3 ,

[0070] In sector III, i a =i s3 i b =i s1 -i s2 i c =i s2 -i s3 ,

[0071] In sector IV, i a =i s3 i b =i s2 -i s3 i c =i s1 -i s2 ,

[0072] In sector V, i a =i s2 -i s3 i b =i s3 i c =i s1 -i s2 ,

[0073] In sector VI, i a =i s1 -i s2 i b =i s3 i c =i s2 -i s3 .

[0074] S3. Based on the reference value i of the effective value of the phase current of the switched reluctance motor rms * Calculate the current reference value i in the synchronous rotating coordinate system. d * i q * i0 * , and current component i d i q By subtracting i0 from i0 and using the vector proportional-integral algorithm, the voltage reference value u of the switched reluctance motor in the synchronous rotating coordinate system is calculated. d u q u0;

[0075] S4. Based on the rotor electrical angle θ of the switched reluctance motor. e , for u d uq By performing a coordinate transformation on u0, the rotating voltage components u of the two converters are obtained. αβ12 and common-mode voltage component CMV 12 Based on the rotating voltage components u of the two converters respectively αβ12 and common-mode voltage component CMV 12 Calculate the conduction time T of the three bridge arms in converter 1 during one switching cycle. 11 T 21 and T 31 The conduction time T of the three bridge arms in converter 2 within one switching cycle 12 T 22 and T 32 ;

[0076] S5. Correct the conduction time of the two converters so that the time for three current samplings within each switching cycle meets the minimum sampling time T. min The requirements are as follows: calculate the duty cycle of each bridge arm, and then obtain the switching signal, which is input to the open winding motor driver to realize the control of the motor.

[0077] Furthermore, such as Figure 4 As shown, the correction of the conduction time of the two converters in S5 includes the following steps:

[0078] S51. Based on the conduction time T of the first bridge arm in converter 1 11 Second bridge arm conduction time T 21 The conduction time T of the third bridge arm 31 Calculate the duration of three current sensor samplings within one switching cycle, where T s Switching cycle for open-winding motor driver:

[0079] Duration T of the first current sensor sampling s1 =(T s -T 11 ) / 2;

[0080] The duration T of the second current sensor sampling s2 =(T 11 -T 21 ) / 2;

[0081] The duration T of the third current sensor sampling s3 =T 21 ;

[0082] S52. Within each sector of converter 1, determine the duration T of the third current sensor sampling. s3 Is it greater than the minimum sampling time T of the current sensor? minIf this condition is not met, then when converter 1 is in sectors I, III, or V, the bridge arm conduction time of converter 1 and converter 2 is corrected as follows: T ’ 21 =T min ;T ’ 12 =T 12 +(T ’ 21 -T 21 When converter 1 is in sectors II, IV, and VI, the conduction time of the bridge arms of converter 1 and converter 2 is corrected as follows: T ’ 21 =T min ;T ’ 32 =T 32 +(T ’ 21 -T 21 ); where the superscript “'” indicates the corrected bridge arm conduction time;

[0083] S53. Within each sector of converter 1, determine the duration T of the second current sensor sampling. s2 Is it greater than the minimum sampling time T of the current sensor? min If this condition is not met, then when converter 1 is in sectors I, III, or V, the bridge arm conduction time of converter 1 and converter 2 is corrected as follows: T ’ 11 =T ’ 21 +2*T min ;T ’ 32 =T 32 +(T ’ 11 -T 11 When converter 1 is in sectors II, IV, and VI, the conduction time of the bridge arms of converter 1 and converter 2 is corrected as follows: T ’ 11 =T ’ 21 +2*T min ;T ’ 22 =T 22 +(T ’ 11 -T 11 ); where the superscript “'” indicates the corrected bridge arm conduction time.

[0084] Furthermore, using the duty cycle calculation module, in different sectors, based on the conduction times of the two converters corrected by S5, and using the logic in Table 1, the duty cycle of each bridge arm is calculated, where D a1 D b1 D c1 D a2 D b2 D c2 They are respectively Figure 5 The duty cycle of the corresponding bridge arm in the open-winding motor driver shown.

[0085] Table 1

[0086]

[0087] The current detection and control system proposed in this invention does not have specific requirements for the type of motor; any type can be used, such as... Figure 5 The motors driven by the open-winding motor driver shown are all applicable.

[0088] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A control method for a switched reluctance motor based on phase-shift-free current reconfiguration, characterized in that, The open-winding motor driver includes converter 1, converter 2, a current sensor, and a position sensor. The open-winding motor driver provides current to a switched reluctance motor. Converter 2 is directly connected between the positive and negative terminals of a DC power supply. Converter 1 and converter 2 are connected by a positive DC bus and a negative DC bus. The current sensor is installed on the negative DC bus between converter 1 and converter 2. The current flowing through the current sensor is only affected by the conduction state of converter 1. The driver includes the following steps: S1. Based on the switching signal of converter 1 in the open-winding motor driver, determine the three sampling points t of the current sensor in each switching cycle. s1 t s2 t s3 First sampling point t s1 The second sampling point t is located at the beginning of the switching cycle of converter 1. s2 Located at the starting point of the first effective vector of transformer 1, the third sampling point t s3 The starting point of the second effective vector located at converter 1; at the three sampling points t s1 t s2 t s3 The current sensor is sampled three times to obtain three corresponding current sample values ​​i. s1 i s2 i s3 ; S2. Based on the reference voltage u of converter 1 α1 and u β1 Determine the operating sector of converter 1, and within different sectors, combine i s1 i s2 i s3 Calculate the three-phase current i of the switched reluctance motor. a i b and i c Perform a rotational coordinate transformation to obtain the current component i in the synchronously rotating coordinate system. d i q and i0; S3. Based on the reference value i of the effective value of the phase current of the switched reluctance motor rms * Calculate the current reference value i in the synchronous rotating coordinate system. d * i q * i0 * , and current component i d i q By subtracting i0 from i0 and using the vector proportional-integral algorithm, the voltage reference value u of the switched reluctance motor in the synchronous rotating coordinate system is calculated. d u q u0; S4. Based on the rotor electrical angle θ of the switched reluctance motor. e , for u d u q By performing a coordinate transformation on u0, the rotating voltage components u of the two converters are obtained. αβ12 and common-mode voltage component CMV 12 Based on the rotating voltage components u of the two converters respectively αβ12 and common-mode voltage component CMV 12 Calculate the conduction time T of the three bridge arms in converter 1 during one switching cycle. 11 T 21 and T 31 The conduction time T of the three bridge arms in converter 2 within one switching cycle 12 T 22 and T 32 ; S5. Correct the conduction time of the two converters so that the time for three current samplings within each switching cycle meets the minimum sampling time T. min The requirements are as follows: calculate the duty cycle of each bridge arm, and then obtain the switching signal, which is input to the open winding motor driver to realize the control of the motor.

2. The method according to claim 1, characterized in that, The calculation method for the three-phase current in different sectors of S2 is as follows: I Ogi Ward, I a =i s1 -i s2 ,i b =i s2 -i s3 ,i c =i s3 ; In sector II, i a =i s2 -i s3 , i b =i s1 -i s2 , i c =i s3 ; III Ogi Ward, i a =i s3 ,i b =i s1 -i s2 ,i c =i s2 -i s3 ; IV Ogi Ward, i a =i s3 ,i b =i s2 -i s3 ,i c =i s1 -i s2 ; V Ogi Ward, i a =i s2 -i s3 ,i b =i s3 ,i c =i s1 -i s2 ; In the VI sector, i a =i s1 -i s2 , i b =i s3 , i c =i s2 -i s3 .

3. The method according to claim 1, characterized in that, Current reference value i in synchronous rotating coordinate system S3 d * i q * i0 * The calculation method is as follows: i d * =0;i q * =i rms * ; 4. The method according to claim 1, characterized in that, The correction of the conduction time of the two converters in S5 includes the following steps: S51. Based on the conduction time T of the first bridge arm in converter 1 11 Second bridge arm conduction time T 21 The conduction time T of the third bridge arm 31 Calculate the duration of three current sensor samplings within one switching cycle, where T s Switching cycle for open-winding motor driver: Duration T of the first current sensor sampling s1 =(T s -T 11 ) / 2; The duration T of the second current sensor sampling s2 =(T 11 -T 21 ) / 2; The duration T of the third current sensor sampling s3 =T 21 ; S52. Within each sector of converter 1, determine the duration T of the third current sensor sampling. s3 Is it greater than the minimum sampling time T of the current sensor? min If this condition is not met, then when converter 1 is in sectors I, III, or V, the bridge arm conduction time of converter 1 and converter 2 is corrected as follows: T ’ 21 =T min ;T ’ 12 =T 12 +(T ’ 21 -T 21 When converter 1 is in sectors II, IV, and VI, the conduction time of the bridge arms of converter 1 and converter 2 is corrected as follows: T ’ 21 =T min ;T ’ 32 =T 32 +(T ’ 21 -T 21 ); where the superscript "'" indicates the corrected bridge arm conduction time; S53. Within each sector of converter 1, determine the duration T of the second current sensor sampling. s2 Is it greater than the minimum sampling time T of the current sensor? min If this condition is not met, then when converter 1 is in sectors I, III, or V, the bridge arm conduction time of converter 1 and converter 2 is corrected as follows: T ’ 11 =T ’ 21 +2*T min ;T ’ 32 =T 32 +(T ’ 11 -T 11 When converter 1 is in sectors II, IV, and VI, the conduction time of the bridge arms of converter 1 and converter 2 is corrected as follows: T ’ 11 =T ’ 21 +2*T min ;T ’ 22 =T 22 +(T ’ 11 -T 11 ); where the superscript "'" indicates the corrected bridge arm conduction time.

5. A switched reluctance motor control system based on phase-shift-free current reconfiguration, characterized in that, It includes an open-winding motor driver, a current detection module, a position detection module, a current controller, a pulse width modulator, a voltage modulation module, and a compensation module for unmeasurable areas; The open-winding motor driver includes converter 1, converter 2, a current sensor, and a position sensor. The open-winding motor driver is used to provide current to the switched reluctance motor. Converter 2 is directly connected between the positive and negative terminals of the DC power supply. Converter 1 and converter 2 are connected by a positive DC bus and a negative DC bus. The current sensor is installed on the negative DC bus between converter 1 and converter 2. The current flowing through the current sensor is only affected by the conduction state of converter 1. The current detection module is used to determine three sampling points t of the current sensor in each switching cycle based on the switching signal of converter 1 in the open-winding motor driver. s1 t s2 t s3 First sampling point t s1 The second sampling point t is located at the beginning of the switching cycle of converter 1. s2 Located at the starting point of the first effective vector of transformer 1, the third sampling point t s3 The starting point of the second effective vector located at converter 1; at the three sampling points t s1 t s2 t s3 The current sensor is sampled three times to obtain three corresponding current sample values ​​i. s1 i s2 i s3 According to the reference voltage u of converter 1 α1 and u β1 Determine the operating sector of converter 1, and within different sectors, combine i s1 i s2 i s3 Calculate the three-phase current i of the switched reluctance motor. a i b and i c Perform a rotational coordinate transformation to obtain the current component i in the synchronously rotating coordinate system. d i q and i0; The position detection module is used to measure the rotor mechanical position θ. m Based on the initial position and number of pole pairs of the switched reluctance motor, the rotor electrical angle θ is calculated. e ; The current controller is used to determine the effective value i of the phase current of the switched reluctance motor. rms * Calculate the current reference value i in the synchronous rotating coordinate system. d * i q * i0 * , and current component i d i q By subtracting i0 from i0 and using the vector proportional-integral algorithm, the voltage reference value u of the switched reluctance motor in the synchronous rotating coordinate system is calculated. d u q u0; The pulse width modulator is used to adjust the rotor electrical angle θ of the switched reluctance motor. e , for u d u q By performing a coordinate transformation on u0, the rotating voltage components u of the two converters are obtained. αβ12 and common-mode voltage component CMV 12 ; The voltage modulation module is used to adjust the voltage based on the rotating voltage components u of the two converters respectively. αβ12 and common-mode voltage component CMV 12 Calculate the conduction time T of the three bridge arms in converter 1 during one switching cycle. 11 T 21 and T 31 The conduction time T of the three bridge arms in converter 2 within one switching cycle 12 T 22 and T 32 ; The unmeasurable region compensation module is used to correct the conduction time of the two converters, so that the time for three current samplings within each switching cycle meets the minimum sampling time T. min Requirements; The duty cycle calculation module is used to calculate the duty cycle of each bridge arm, thereby obtaining the switching signal, which is then input to the open winding motor driver to control the motor.

6. The system according to claim 5, characterized in that, The calculation method for the three-phase current of different sectors in the open-winding motor driver is as follows: I Ogi Ward, I a =i s1 -i s2 ,i b =i s2 -i s3 ,i c =i s3 ; In sector II, i a =i s2 -i s3 ,i b =i s1 -i s2 ,i c =i s3 ; III Ogi Ward, i a =i s3 ,i b =i s1 -i s2 ,i c =i s2 -i s3 ; IV Ogi Ward, i a =i s3 ,i b =i s2 -i s3 ,i c =i s1 -i s2 ; V Ogi Ward, i a =i s2 -i s3 ,i b =i s3 ,i c =i s1 -i s2 ; In the VI sector, i a =i s1 -i s2 , i b =i s3 , i c =i s2 -i s3 .

7. The system according to claim 5, characterized in that, The current reference value i in the synchronous rotating coordinate system of the current controller d * i q * i0 * The calculation method is as follows: i d * =0;i q * =i rms * ; 8. The system according to claim 5, characterized in that, The correction of the conduction time of the two converters in the unmeasurable region compensation module includes the following steps: S51. Based on the conduction time T of the first bridge arm in converter 1 11 Second bridge arm conduction time T 21 The conduction time T of the third bridge arm 31 Calculate the duration of three current sensor samplings within one switching cycle, where T s Switching cycle for open-winding motor driver: Duration T of the first current sensor sampling s1 =(T s -T 11 ) / 2; The duration T of the second current sensor sampling s2 =(T 11 -T 21 ) / 2; The duration T of the third current sensor sampling s3 =T 21 ; S52. Within each sector of converter 1, determine the duration T of the third current sensor sampling. s3 Is it greater than the minimum sampling time T of the current sensor? min If this condition is not met, then when converter 1 is in sectors I, III, or V, the bridge arm conduction time of converter 1 and converter 2 is corrected as follows: T' 21 =T min ;T' 12 =T 12 +(T' 21 -T 21 When converter 1 is in sectors II, IV, and VI, the conduction time of the bridge arms of converter 1 and converter 2 is corrected as follows: T' 21 =T min ;T' 32 =T 32 +(T' 21 -T 21 ); where the superscript "'" indicates the corrected bridge arm conduction time; S53. Within each sector of converter 1, determine the duration T of the second current sensor sampling. s2 Is it greater than the minimum sampling time T of the current sensor? min If this condition is not met, then when converter 1 is in sectors I, III, or V, the bridge arm conduction time of converter 1 and converter 2 is corrected as follows: T' 11 =T' 21 +2*T min ;T' 32 =T 32 +(T' 11 -T 11 When converter 1 is in sectors II, IV, and VI, the conduction time of the bridge arms of converter 1 and converter 2 is corrected as follows: T' 11 =T' 21 +2*T min ;T' 22 =T 22 +(T' 11 -T 11 ); where the superscript "'" indicates the corrected bridge arm conduction time.

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