Segmented control method of torque distribution function of switched reluctance motor based on fuzzy control

Abstract

The present invention discloses a fuzzy-control-based segmented control method for a switched reluctance motor torque distribution function. The method comprises the following steps: constructing a mathematical model of the switched reluctance motor; segmentedly controlling the torque of different phases of the switched reluctance motor to maintain a constant sum of torques using a torque distribution function, wherein the torque distribution function aims to maintain a constant synthetic instantaneous torque. The method distributes the desired torque of each phase at different positions using the torque distribution function, controls the synthetic instantaneous torque to track the command torque output by a position closed-loop or speed closed-loop controller, and controls the rate of change of the torque to achieve balanced commutation; and suppresses torque ripple by selecting the optimal duty cycle at different speeds and torques using a fuzzy control algorithm. By using the torque distribution function method, the method aims to maintain a constant synthetic instantaneous torque, controls the rate of change of the torque to achieve balanced commutation, and then automatically selects the optimal duty cycle at different speeds and torques using a fuzzy control algorithm to suppress torque ripple.

Description

Technical Field

[0001] The present invention belongs to the technical field of switched reluctance motor control in the field of electrical engineering, and in particular relates to a fuzzy control-based switched reluctance motor torque distribution function segmented control method and system. Background Art

[0002] The switched reluctance motor (SRM or SR motor) is a new type of motor that has developed rapidly in the past decade. It features high starting torque, a wide speed regulation range, flexible control, easy four-quadrant operation, strong regenerative braking capability, and high efficiency across a wide speed and power range, contributing to energy conservation and consumption reduction. It can operate at extremely high speeds, operate in phase loss, and has strong fault tolerance. It is now widely used in aerospace, electric vehicles, oilfield mining, and household appliances.

[0003] Compared to traditional motors, the SRM's bi-salient structure and switch-mode power supply characteristics result in significant torque ripple, directly impacting the system's output characteristics. Common control methods to reduce torque ripple include current chopping control, torque distribution function control, PI control, and direct torque control. However, if conventional control methods are used to switch phase currents on and off, the torque increase generated by the on-phase current is insufficient to offset the torque decrease caused by the off-phase current, resulting in a significant drop in the resulting instantaneous torque. This exacerbates the torque ripple problem during commutation.

[0004] Publication No. CN 111654218 A discloses a switched reluctance motor torque distribution function control system using improved fuzzy control. The system comprises a position detection module, an improved fuzzy control module, a torque distribution function module, a torque characteristic table estimation module, a torque hysteresis module, a power converter module, and a switched reluctance motor. The outer loop of this control system utilizes an improved fuzzy control method. The improved fuzzy control module self-tunes the proportional factors Ke and Ku and transmits the given torque to the torque distribution function module. The inner loop of this control system utilizes a cosine distribution function to control the torque distribution function. This allows the torque distribution function's opening angle to be greater than the motor's actual opening angle, enabling torque distribution to begin when the inductance change rate is significantly different, thereby ensuring that the motor's actual torque better tracks the given torque. However, this method, which uses fuzzy control of the proportional factors Ke and Ku, fails to effectively suppress torque ripple. This is the reason for the present invention. Summary of the Invention

[0005] 1. Purpose of the present invention

[0006] In response to the technical problem of severe torque pulsation caused by the dual-pole structure of the SRM itself, a segmented control method and system for the torque distribution function of the switched reluctance motor based on fuzzy control is proposed. The present invention combines the fuzzy control algorithm to perform fuzzy control on the segmented control strategy of the torque distribution function to obtain the optimal duty cycle, thereby reducing the torque pulsation.

[0007] 2. Technical solution adopted by the present invention

[0008] A fuzzy control-based torque distribution function segmented control method for a switched reluctance motor comprises the following steps:

[0009] S01: Construct a mathematical model of the switched reluctance motor;

[0010] S02: controlling the sum of the torques of different phases of the switched reluctance motor to be constant by segmented control using a torque distribution function, wherein the torque distribution function aims to maintain a constant synthetic instantaneous torque. The desired torques of the phases at different positions are distributed by the torque distribution function, and the synthetic instantaneous torque is controlled to track the command torque output by the position closed-loop or speed closed-loop controller, thereby controlling the rate of change of the torque to achieve balanced commutation;

[0011] S03: The optimal duty cycle at different speeds and torques is selected through the fuzzy control algorithm to suppress torque pulsation.

[0012] In a preferred technical solution, the mathematical model of the switched reluctance motor in step S01 includes:

[0013] In the magnetic saturation state, the electromagnetic torque of the SRM linear model is:

[0014]

[0015] Where, T e , i, L, and θ are the electromagnetic torque, motor winding current, motor winding inductance, and rotor position angle, respectively;

[0016] According to the laws of mechanics, the mechanical equation of the switched reluctance motor is:

[0017]

[0018] Where, T e 、T k ,m,J,ω,T L , F are the electromagnetic torque, the torque generated during the operation of the k-th phase winding, the number of phases of the motor, the moment of inertia of the motor, the angular velocity of the rotor, the load torque and the damping coefficient respectively; the angular velocity of the rotor is:

[0019]

[0020] In the preferred technical solution, the torque distribution function segmented control method in step S02 includes:

[0021] (1) Build a torque distribution control system to output the synthetic reference torque T required by the SR motor through the speed PI regulator ref According to the current rotor position θ, the desired torque T corresponding to A, B, and C is obtained from the torque distribution function. Aref 、T Bref 、T Cref , and the instantaneous torque tracking T is generated by the SR motor torque inverse model i(T, θ) ref The expected phase current i Aref 、i Bref 、i Cref , then the phase current is controlled to track the desired phase current through CCC controller or voltage PWM;

[0022] (2) According to the control target of torque distribution, the distribution function is defined as f k (θ):

[0023]

[0024] The sinusoidal type is selected as the torque distribution function, and its expression is:

[0025]

[0026] Where θ on is the opening angle of the k-phase winding; θ off The starting position angle for the conducting phase k to reduce the electromagnetic torque according to the rule set by TSF; θ ov is the overlapping angle of the adjacent two phase currents, τ is the rotor period angle.

[0027] In the preferred technical solution, the step S03 further includes debugging the optimal duty cycle to minimize the torque ripple, making the actual torque waveform infinitely close to the expected torque waveform, and dividing the sinusoidal TSF waveform into the first overlapping area, i.e., θ on ≤θ≤θ ov , unidirectional conduction region, i.e. θ on +θ ov ≤θ≤θ off and the second overlapping region, i.e., θ off ≤θ≤θ off +θ ov ; In these three areas, the optimal duty cycle corresponding to the torque of X n·m, Y n·m, and Z n·m is obtained at the speed of A rpm, B rpm, and C rpm respectively.

[0028] In the preferred technical solution, in step S03, the optimal duty cycle at different rotational speeds and torques is selected through a fuzzy control algorithm, including:

[0029] S31: Combine the rotational speed and torque pairwise to obtain:

[0030] When 0 < n ≤ A and 0 < T ≤ X, output y = N1L1;

[0031] When 0 < n ≤ A and X < T ≤ Y, output y = N1L2;

[0032] When 0 < n ≤ A and Y < T ≤ Z, output y = N1L3;

[0033] When A < n ≤ B and 0 < T ≤ X, output y = N2L1;

[0034] When A < n ≤ B and X < T ≤ Y, output y = N2L2; <ooo0269>

[0035] When A < n ≤ B and Y < T ≤ Z, output y = N2L2;

[0036] When B < n ≤ C and 0 < T ≤ X, output y = N3L1;

[0037] When B < n ≤ C and X < T ≤ Y, output y = N3L2;

[0038] When B < n ≤ C and X < T ≤ Y, output y = N3L3; <ooo0277>

[0039] S32: Output the optimal duty cycle:

[0040] ① When θ on ≤ θ ≤ θ ov At this time

[0041] If the combination is N1L1, then output: D 励 = τ 11

[0042] D 退 = α 11

[0043] Among them, D 励 is the excitation duty cycle, and D 退 is the demagnetization duty cycle;

[0044] If the combination is N1L2, then output:

[0045]

[0046]

[0047] If the combination is N1L3, then output:

[0048]

[0049]

[0050] If the combination is N2L1, the output is:

[0051]

[0052]

[0053] If the combination is N2L2, the output is:

[0054]

[0055]

[0056] Among them, the speed change ΔN = N-N0, N is the actual speed, N0 is the rated speed, the torque change ΔT = T-T0, T is the actual torque, T0 is the rated torque;

[0057] If the combination is N2L3, the output is:

[0058]

[0059]

[0060] If the combination is N3L1, the output is:

[0061]

[0062]

[0063] If the combination is N3L2, the output is:

[0064]

[0065]

[0066] If the combination is N3L3, the output is:

[0067]

[0068]

[0069] ②θ on +θ ov ≤θ≤θ off

[0070] If the combination is N1L1, the output is:

[0071] D励 =β 11

[0072] D 退 =δ 11

[0073] If the combination is N1L2, the output is:

[0074]

[0075]

[0076] If the combination is N1L3, the output is:

[0077]

[0078]

[0079] If the combination is N2L1, the output is:

[0080]

[0081]

[0082] If the combination is N2L2, the output is:

[0083]

[0084]

[0085] If the combination is N2L3, the output is:

[0086]

[0087]

[0088] If the combination is N3L1, the output is:

[0089]

[0090]

[0091] If the combination is N3L2, the output is:

[0092]

[0093]

[0094] If the combination is N3L3, the output is:

[0095]

[0096]

[0097] ③θ off ≤θ≤θ off +θ ov

[0098] If the combination is N1L1, the output is:

[0099]

[0100] D 退 =ω 11

[0101] If the combination is N1L2, the output is:

[0102]

[0103]

[0104] If the combination is N1L3, the output is:

[0105]

[0106]

[0107] If the combination is N2L1, the output is:

[0108]

[0109]

[0110] If the combination is N2L2, the output is:

[0111]

[0112]

[0113] If the combination is N2L3, the output is:

[0114]

[0115]

[0116] If the combination is N3L1, the output is:

[0117]

[0118]

[0119] If the combination is N3L2, the output is:

[0120]

[0121]

[0122] If the combination is N3L3, the output is:

[0123]

[0124]

[0125] Among them, τ ij , α ij , β ij , δ ij , ω ij The optimal duty cycle obtained by debugging is i=1, 2, 3, j=1, 2, 3.

[0126] The present invention also discloses a fuzzy control-based switched reluctance motor torque distribution function segmented control system, comprising:

[0127] A switched reluctance motor mathematical model construction module is used to construct a mathematical model of the switched reluctance motor;

[0128] A torque distribution control system that controls the sum of the torques of the different phases of the switched reluctance motor in sections to maintain a constant sum through a torque distribution function. The torque distribution function aims to maintain a constant composite instantaneous torque. The torque distribution function distributes the desired torques of the phases at different positions, controls the composite instantaneous torque to track the command torque output by the position closed-loop or speed closed-loop controller, and controls the rate of change of the torque to achieve balanced commutation.

[0129] The fuzzy control module selects the optimal duty cycle at different speeds and torques through the fuzzy control algorithm to suppress torque pulsation.

[0130] In a preferred technical solution, the mathematical model of the switched reluctance motor includes:

[0131] In the magnetic saturation state, the electromagnetic torque of the SRM linear model is:

[0132]

[0133] Where, T e , i, L, and θ are the electromagnetic torque, motor winding current, motor winding inductance, and rotor position angle, respectively;

[0134] According to the laws of mechanics, the mechanical equation of the switched reluctance motor is:

[0135]

[0136] Where, Te 、T k ,m,J,ω,T L , F are the electromagnetic torque, the torque generated during the operation of the k-th phase winding, the number of phases of the motor, the moment of inertia of the motor, the angular velocity of the rotor, the load torque and the damping coefficient respectively; the angular velocity of the rotor is:

[0137]

[0138] In a preferred technical solution, the torque distribution function segmented control method of the torque distribution control system includes:

[0139] (1) The synthetic reference torque T required by the SR motor is output through the speed PI regulator ref According to the current rotor position θ, the desired torque T corresponding to A, B, and C is obtained from the torque distribution function. Aref 、T Bref 、T Cref , and the instantaneous torque tracking T is generated by the SR motor torque inverse model i(T, θ) ref The expected phase current i Aref 、i Bref 、i Cref , then the phase current is controlled to track the desired phase current through CCC controller or voltage PWM;

[0140] (2) According to the control target of torque distribution, the distribution function is defined as f k (θ):

[0141]

[0142] The sinusoidal type is selected as the torque distribution function, and its expression is:

[0143]

[0144] Where θ on is the opening angle of the k-phase winding; θ off The starting position angle for the conducting phase k to reduce the electromagnetic torque according to the rule set by TSF; θ ov is the overlapping angle of the adjacent two phase currents, τ is the rotor period angle.

[0145] In the preferred technical solution, the fuzzy control module further includes debugging the optimal duty cycle to minimize the torque ripple, making the actual torque waveform infinitely close to the expected torque waveform, and dividing the sinusoidal TSF waveform into the first overlapping area, namely θ on ≤θ≤θ ov , unidirectional conduction region, i.e. θ on +θ ov ≤θ≤θoff and the second overlapping region, i.e., θ off ≤θ≤θ off +θ ov ; In these three areas, the optimal duty cycle corresponding to the torque of X n·m, Y n·m, and Z n·m is obtained at the speed of A rpm, B rpm, and C rpm respectively.

[0146] 3. Beneficial effects of the present invention

[0147] The torque distribution function method of the present invention aims to achieve constant instantaneous torque by controlling the rate of change of torque to achieve balanced commutation. A fuzzy control algorithm then automatically selects the optimal duty cycle at different speeds and torques to suppress and reduce torque ripple. This method is simple, effective, and requires minimal computation. BRIEF DESCRIPTION OF THE DRAWINGS

[0148] Figure 1 This is a flow chart of the segmented control method of the torque distribution function of the switched reluctance motor based on fuzzy control of the present invention;

[0149] Figure 2 The figure is a block diagram of the torque indirect control system based on the TSF method of the present invention;

[0150] Figure 3 This is the sinusoidal TSF waveform diagram of the present invention;

[0151] Figure 4 This is a principle block diagram of the torque distribution function segmented control system of the switched reluctance motor based on fuzzy control of the present invention. DETAILED DESCRIPTION

[0152] The following is a clear and complete description of the technical solutions in the examples of the present invention, in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0153] The examples of the present invention will be described in further detail below with reference to the accompanying drawings.

[0154] Example 1

[0155] like Figure 1 As shown, a fuzzy control-based switched reluctance motor torque distribution function segmented control method includes the following steps:

[0156] S01: Construct a mathematical model of the switched reluctance motor;

[0157] S02: controlling the sum of the torques of different phases of the switched reluctance motor to be constant by segmented control using a torque distribution function, wherein the torque distribution function aims to maintain a constant synthetic instantaneous torque. The desired torques of the phases at different positions are distributed by the torque distribution function, and the synthetic instantaneous torque is controlled to track the command torque output by the position closed-loop or speed closed-loop controller, thereby controlling the rate of change of the torque to achieve balanced commutation;

[0158] S03: The optimal duty cycle at different speeds and torques is selected through the fuzzy control algorithm to suppress torque pulsation.

[0159] In a preferred embodiment, the mathematical model of the switched reluctance motor in step S01 includes:

[0160] In the magnetic saturation state, the electromagnetic torque of the SRM linear model is:

[0161]

[0162] Where, T e , i, L, and θ are the electromagnetic torque, motor winding current, motor winding inductance, and rotor position angle, respectively;

[0163] According to the laws of mechanics, the mechanical equation of the switched reluctance motor is:

[0164]

[0165] Where, T e 、T k ,m,J,ω,T L , F are the electromagnetic torque, the torque generated during the operation of the k-th phase winding, the number of phases of the motor, the moment of inertia of the motor, the angular velocity of the rotor, the load torque and the damping coefficient respectively; the angular velocity of the rotor is:

[0166]

[0167] In a preferred embodiment, the torque distribution function segmented control method in step S02 includes:

[0168] (1) Build a torque distribution control system, such as Figure 2 As shown, the synthetic reference torque T required by the SR motor is output through the speed PI regulator. ref According to the current rotor position θ, the desired torque T corresponding to A, B, and C is obtained from the torque distribution function. Aref 、T Bref 、T Cref , and the instantaneous torque tracking T is generated by the SR motor torque inverse model i(T, θ) ref The expected phase current i Aref 、i Bref 、i Cref, and then the phase current is controlled by the CCC controller or voltage PWM to track the desired phase current;

[0169] (2) According to the control objective of torque distribution, the distribution function is defined as f k (θ):

[0170]

[0171] Select the sine type as the torque distribution function, and its expression is:

[0172]

[0173] In the formula, θ on is the conduction angle of the k-phase winding; θ off is the starting position angle at which the electromagnetic torque of the conducting phase k starts to decrease according to the law set by the TSF; θ ov is the angle of overlap of adjacent phase currents, τ is the rotor period angle.

[0174] In a preferred embodiment, before step S03, it further includes debugging the optimal duty cycle to minimize torque ripple and making the actual torque waveform infinitely close to the desired torque waveform. As Figure 3 shown, the sine-type TSF waveform is divided into the first overlap region, that is, θ on ≤ θ ≤ θ ov , the unidirectional conduction region, that is, θ on + θ ov ≤ θ ≤ θ off and the second overlap region, that is, θ off ≤ θ ≤ θ off + θ ov ; In these three regions, the optimal duty cycles corresponding to the torques of X n·m, Y n·m, and Z n·m at rotational speeds of A rpm, B rpm, and C rpm are obtained respectively.

[0175] In a preferred embodiment, in step S03, the optimal duty cycle at different rotational speeds and torques is selected by the fuzzy control algorithm, including:

[0176] S31: Combine the rotational speed and torque pairwise to obtain:

[0177] When 0 < n ≤ A and 0 < T ≤ X, output y = N1L1;

[0178] When 0 < n ≤ A and X < T ≤ Y, output y = N1L2;

[0179] When 0 < n ≤ A and Y < T ≤ Z, output y = N1L3;

[0180] When A < n ≤ B and 0 < T ≤ X, output y = N2L1;

[0181] When A < n ≤ B and X < T ≤ Y, output y = N2L2;

[0182] When A < n ≤ B and Y < T ≤ Z, output y = N2L3;

[0183] When B < n ≤ C and 0 < T ≤ X, output y = N3L1;

[0184] When B < n ≤ C and X < T ≤ Y, output y = N3L2;

[0185] When B < n ≤ C and X < T ≤ Y, output y = N3L3;

[0186] S32: Output the optimal duty cycle:

[0187] ① When θ on ≤ θ ≤ θ ov When

[0188] If the combination is N1L1, then output: D 励 = τ 11

[0189] D 退 = α 11

[0190] Where D 励 is the excitation duty cycle, and D 退 is the demagnetization duty cycle;

[0191] If the combination is N1L2, then output:

[0192]

[0193]

[0194] If the combination is N1L3, then output:

[0195]

[0196]

[0197] If the combination is N2L1, then output:

[0198]

[0199]

[0200] If the combination is N2L2, then output:

[0201]

[0202]

[0203] Among them, the speed change ΔN = N-N0, N is the actual speed, N0 is the rated speed, the torque change ΔT = T-T0, T is the actual torque, T0 is the rated torque;

[0204] If the combination is N2L3, the output is:

[0205]

[0206]

[0207] If the combination is N3L1, the output is:

[0208]

[0209]

[0210] If the combination is N3L2, the output is:

[0211]

[0212]

[0213] If the combination is N3L3, the output is:

[0214]

[0215]

[0216] ②θ on +θ ov ≤θ off

[0217] If the combination is N1L1, the output is:

[0218] D 励 =β 11

[0219] D 退 =δ 11

[0220] If the combination is N1L2, the output is:

[0221]

[0222]

[0223] If the combination is N1L3, the output is:

[0224]

[0225]

[0226] If the combination is N2L1, the output is:

[0227]

[0228]

[0229] If the combination is N2L2, the output is:

[0230]

[0231]

[0232] If the combination is N2L3, the output is:

[0233]

[0234]

[0235] If the combination is N3L1, the output is:

[0236]

[0237]

[0238] If the combination is N3L2, the output is:

[0239]

[0240]

[0241] If the combination is N3L3, the output is:

[0242]

[0243]

[0244] ③θ off ≤θ≤θ off +θ ov

[0245] If the combination is N1L1, the output is:

[0246]

[0247] D 退 =ω 11

[0248] If the combination is N1L2, the output is:

[0249]

[0250]

[0251] If the combination is L1L3, the output is:

[0252]

[0253]

[0254] If the combination is N2L1, the output is:

[0255]

[0256]

[0257] If the combination is N2L2, the output is:

[0258]

[0259]

[0260] If the combination is N2L3, the output is:

[0261]

[0262]

[0263] If the combination is L3L1, the output is:

[0264]

[0265]

[0266] If the combination is L3L3, the output is:

[0267]

[0268]

[0269] If the combination is N3L3, the output is:

[0270]

[0271]

[0272] Among them, τ ij , α ij , β ij , δij , ω ij The optimal duty cycle obtained by debugging is i=1, 2, 3, j=1, 2, 3.

[0273] Another embodiment, such as Figure 4 As shown, the present invention also discloses a switched reluctance motor torque distribution function segmented control system based on fuzzy control, comprising:

[0274] A switched reluctance motor mathematical model building module 10 is used to build a mathematical model of the switched reluctance motor;

[0275] The torque distribution control system 20 controls the sum of the torques of the different phases of the switched reluctance motor in sections by using a torque distribution function. The torque distribution function aims to maintain a constant composite instantaneous torque. The torque distribution function distributes the desired torques of the phases at different positions, controls the composite instantaneous torque to track the command torque output by the position closed-loop or speed closed-loop controller, and controls the rate of change of the torque to achieve balanced commutation.

[0276] The fuzzy control module 30 selects the optimal duty cycle under different speeds and torques through a fuzzy control algorithm to suppress torque pulsation.

[0277] The following describes in detail the process of the switched reluctance motor torque distribution function segmented control system based on fuzzy control by taking a preferred embodiment as an example:

[0278] Step 1: Establishment of the mathematical model of the switched reluctance motor

[0279] The stator and rotor of the switched reluctance motor are both salient pole structures. Therefore, the magnetic field distribution varies with the relative position of the rotor salient poles and the salient poles of the stator energized phase. Under magnetic saturation, the electromagnetic torque expression of the SRM linear model is:

[0280]

[0281] Where, T e , i, L, and θ are the electromagnetic torque, motor winding current, motor winding inductance, and rotor position angle, respectively.

[0282] According to the laws of mechanics, the mechanical equation of the switched reluctance motor is:

[0283]

[0284] Where, T e 、T k ,m,j,ω,θ,T L, F are the electromagnetic torque, the torque generated by the k-th phase winding during operation, the number of phases of the motor, the moment of inertia of the motor, the angular velocity of the rotor, the rotor position angle, the load torque and the damping coefficient. The rotor angular velocity is:

[0285]

[0286] From equations (2) and (3), it can be seen that when the total electromagnetic torque generated by each phase of the motor is not equal to the load torque and its own damping loss, the motor will generate acceleration and the speed will change.

[0287] Step 2: Introduce torque distribution function segmented control

[0288] The torque ripple of SR motor is mainly caused by the nonlinear characteristics of electromagnetic torque generated by each phase and the discreteness of phase winding excitation. In order to quantify the torque ripple of SR motor, the torque ripple rate k is defined T for:

[0289]

[0290] Where, T max 、T min are the maximum and minimum values ​​of the synthetic instantaneous torque respectively; T avg is the average value of the resultant torque.

[0291] When commutating the phase windings of an SR motor, conventional control methods, such as switching the phase current on and off, result in an insufficient increase in torque from the on-phase to offset the decrease in torque from the off-phase. This results in a significant drop in the resulting instantaneous torque, making torque ripple more prominent during commutation. To address this, the torque distribution function (TSF) aims to synthesize instantaneous torque. The torque distribution function (TSF) distributes the desired torque to each phase at different positions. Through torque / flux / current hysteresis control or torque / flux / current PWM control, the resulting instantaneous torque tracks the command torque output by the position or speed closed-loop controller. During commutation, the TSF method controls the rate of change of torque rather than the rate of change of phase current to achieve balanced commutation and suppress torque ripple.

[0292] Reasonable design of TSF is very important for high-performance SR motor control. It is generally designed according to the following principles: each phase only produces positive (motor) torque; at any instant, only one winding or two adjacent windings are energized.

[0293] There are four typical TSF types: linear, exponential, sinusoidal, and cubic.

[0294] Next, we will explain the specific steps of step 2:

[0295] Since the total output torque of a switched reluctance motor is the sum of the torques generated by all windings at the same time, in order to reduce the total torque ripple, the torque distribution function can be used to calculate the torque of each phase separately to keep the sum of the different torques constant.

[0296] (1) Selection of torque distribution control system

[0297] like Figure 2 As shown, the speed PI regulator outputs the synthetic reference torque T required by the SR motor. ref According to the current rotor position θ, the desired torque T corresponding to A, B, and C is obtained from the torque distribution function. Aref 、T Bref 、T Cref , and the instantaneous torque tracking T is generated by the SR motor torque inverse model i(T, θ) ref The expected phase current i Aref 、i Bref 、i Cref , and then the phase current is controlled by CCC controller or voltage PWM to track the desired phase current to achieve minimum torque ripple control.

[0298] (2) Determine the torque distribution function

[0299] According to the control target of torque distribution, the distribution function is defined as f k (θ):

[0300]

[0301] The sine type is selected as the torque distribution function, and its expression is: (τ is the rotor period angle)

[0302]

[0303] Where θ on is the opening angle of the k-phase winding; θ off The starting position angle for the conducting phase k to reduce the electromagnetic torque according to the rule set by TSF; θ ov is the angle of overlap of the adjacent two-phase currents, and θ ov The following requirements should be met:

[0304] (τ is the rotor period angle)

[0305] The waveform of the sinusoidal distribution function is as follows Figure 3 shown.

[0306] In Matlab-Simulink, we build a simulation with three phases A, B, and C. Since the principles of each phase are roughly the same, we take phase A as an example:

[0307] Assignment function: Program the sinusoidal TSF function in the Function module of Simulink with if-end statement, and input is θ on ,θ off ,θ ov and the rotor position angle θ, the output is y (i.e. the desired torque T Aref ); Z is the segmentation condition; and w has output only when the angle is within the conduction range (i.e., w = 1).

[0308]

[0309] Torque inverse model: It is a table consisting of the rotor position angle θ on the horizontal axis and the reference torque T on the vertical axis. The expected current i can be obtained by looking up the table with the input rotor position angle and the expected torque. Aref .

[0310] The power converter adopts a three-phase asymmetric half-bridge topology. Each phase consists of two IGBT pairs V1 and V2 (insulated gate bipolar transistors) and two freewheeling diodes V D1 、V D2 When V1 and V2 are turned on, power is applied to both ends of the A phase winding, generating a phase current i A , at this time it is in the excitation state; when V1 and V2 are turned off, the A-phase winding generates a transformer electromotive force, then V D1 、V D2 When the winding is forward-conducted, the voltage across the winding is equal to the negative power supply voltage, and the current drops rapidly. This is the demagnetization state.

[0311] The CCC controller is simply a current chopping control. Aref and the phase current i detected by A The pulse input of the power converter is obtained through current chopping control to make the phase current track the desired current, thereby realizing indirect torque control.

[0312] It is also programmed in the Function module in Simulink, with the inputs conduction, detI(i Aref -i A ), pulse width (maximum current minus minimum current); the output is y1, y2.

[0313]

[0314] y1=1, y2=1 represents that the working state is excitation, y1=0, y2=0 represents that the working state is demagnetization, and y1=0, y2=1 represents that the working state is continuous flow.

[0315] Because during excitation, i.e., y1=1, y2=1, the current surge will be very large within a switching cycle, so it is necessary to increase the duty cycle to limit it. (Change the value of y1 during excitation and demagnetization, y1∈[0,1])

[0316] Here, we take the speeds A rpm, B rpm, and C rpm, and the corresponding torques X n·m, Y n·m, and Z n·m, respectively, to discuss and find their corresponding optimal duty ratios. (The method for negative torque speed is roughly the same as that for positive torque speed.)

[0317] Step 3: Debug the optimal duty cycle

[0318] The so-called debugging of the optimal duty cycle is to minimize the torque pulsation and make the actual torque waveform as close as possible to the expected torque waveform.

[0319] It can be seen from the sinusoidal TSF waveform that it can be divided into three areas (θ on ≤θ≤θ ov ,θ on +θ ov ≤θ≤θ off ,θ off ≤θ≤θ off +θ ov ), two overlapping regions (excitation and demagnetization), and a forward conduction region. In these three regions, find the optimal duty cycle for the three speed and torque groups.

[0320] 1. The first overlapping area (θ on ≤θ≤θ ov )

[0321] The optimal duty cycle D at this time is shown in the following table:

[0322] excitation:

[0323]

[0324]

[0325] demagnetization:

[0326]

[0327] 2. One-way conduction area (θ on +θ ov ≤θ≤θ off )

[0328] The optimal duty cycle D at this time is shown in the following table:

[0329] excitation:

[0330]

[0331] Demagnetization:

[0332]

[0333] 3. The second overlapping region (θ off ≤ θ ≤ θ off + θ ov )

[0334] The optimal duty cycle D at this time is shown in the following table:

[0335] Magnetization:

[0336]

[0337] Demagnetization:

[0338]

[0339] The optimal duty cycle has been fully debugged至此最优占空比已全部调试完成。

[0340] Step 4: Introduce a fuzzy control algorithm to select the optimal duty cycle at each speed and torque

[0341] Since in the actual operation of the SR motor, the speed and torque cannot always be the values we set. And it is known that the duty cycle changes linearly in a certain proportion. Therefore, here I introduce a fuzzy control algorithm to control the selection of the optimal duty cycle at different speeds and torques.由于在SR电动机实际运行当中,转速与转矩不可能一直为我们所设定的那几个值。而又知占空比是按一定的比例线性变化的,所以,这里我引入了模糊控制算法,来控制在不同转速转矩下对最优占空比的选择。

[0342] The following are the specific steps of the fuzzy control:下面是模糊控制具体步骤:

[0343] Program in the Function module of Matlab-Simulink.在Matlab-Simulink里的Function模块里编程。

[0344] 1) The input quantities are the speed n and the desired torque T, and the output quantity is the duty cycle D.输入量为转速n和期望转矩T,输出量为占空比D。

[0345] ① When 0 < n ≤ A, the output y = N1;

[0346] When A < n ≤ B, the output y = N2;

[0347] When B < n ≤ C, the output y = N3.

[0348] ② When 0 < T ≤ X, the output y = L1;

[0349] When X < T ≤ Y, the output y = L2;

[0350] When Y < T ≤ Z, the output y = L3

[0351] From the above ①②, the following table can be obtained:由上述①②可得下表:

[0352]

[0353]

[0354] 2) When 0 < n ≤ A and 0 < T ≤ X, the output y = N1L1;

[0355] When 0 < n ≤ A and X < T ≤ Y, the output y = N1L2;

[0356] When 0 < n ≤ A and Y < T ≤ Z, the output y = N1L3;

[0357] When A < n ≤ B and 0 < T ≤ X, the output y = N2L1;

[0358] When A < n ≤ B and X < T ≤ Y, the output y = N2L2;

[0359] When A < n ≤ B and Y < n ≤ Z, the output y = N2L3;

[0360] When B < n ≤ C and 0 < T ≤ X, the output y = N3L1;

[0361] When B < n ≤ C and X < T ≤ Y, the output y = N3L2;

[0362] When B < n ≤ C and X < T ≤ Y, the output y = N3L3;

[0363] 3) Obtain the rotational speed change ΔN = N - N0 (N is the actual rotational speed and N0 is the rated rotational speed)

[0364] Obtain the torque change ΔT = T - T0 (T is the actual torque and T0 is the rated torque)

[0365] ① θ on ≤ θ ≤ θ ov

[0366] If the above judgment combination is N1L1, then the output D is:

[0367] D 励 = τ 11

[0368] D 退 = α 11

[0369] If the combination is N1L2, then the output D is:

[0370]

[0371]

[0372] If the combination is N1L3, then the output D is:

[0373]

[0374]

[0375] If the combination is N2L1, the output D is:

[0376]

[0377]

[0378] If the combination is N2L2, the output D is:

[0379]

[0380]

[0381] If the combination is N2L3, the output D is:

[0382]

[0383]

[0384] If the combination is N3L1, the output D is:

[0385]

[0386]

[0387] If the combination is N3L2, the output D is:

[0388]

[0389]

[0390] If the combination is N3L3, the output D is:

[0391]

[0392]

[0393] ②θ on +θ ov ≤θ≤θ off

[0394] If the above judgment combination is N1L1, the output D is:

[0395] D 励 =β 11

[0396] D 退 =δ 11

[0397] If the combination is N1L2, the output D is:

[0398]

[0399]

[0400] If the combination is N1L3, the output D is:

[0401]

[0402]

[0403] If the combination is N2L1, the output D is:

[0404]

[0405]

[0406] If the combination is N2L2, the output D is:

[0407]

[0408]

[0409] If the combination is N2L3, the output D is:

[0410]

[0411]

[0412] If the combination is N3L1, the output D is:

[0413]

[0414]

[0415] If the combination is N3L2, the output D is:

[0416]

[0417]

[0418] If the combination is N3L3, the output D is:

[0419]

[0420]

[0421] ③θ off≤θ≤θ off +θ ov

[0422] If the above judgment combination is N1L1, the output D is:

[0423]

[0424] D 退 =ω 11

[0425] If the combination is N1L2, the output D is:

[0426]

[0427]

[0428] If the combination is N1L3, the output D is:

[0429]

[0430]

[0431] If the combination is N2L1, the output D is:

[0432]

[0433]

[0434] If the combination is N2L2, the output D is:

[0435]

[0436]

[0437] If the combination is N2L3, the output D is:

[0438]

[0439]

[0440] If the combination is N3L1, the output D is:

[0441]

[0442]

[0443] If the combination is N3L2, the output D is:

[0444]

[0445]

[0446] If the combination is N3L3, the output D is:

[0447]

[0448]

[0449] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A fuzzy control-based torque distribution function segmented control method for a switched reluctance motor, characterized in that: It includes the following steps: S01: Construct the mathematical model of the switched reluctance motor; S02: Control the sum of torques of different phases of the switched reluctance motor to be constant in segments through the torque distribution function. The torque distribution function aims at a constant synthetic instantaneous torque, distributes the expected torque of each phase at different positions through the torque distribution function, and controls the synthetic instantaneous torque to track the command torque output by the position closed-loop or speed closed-loop controller, and controls the change rate of the torque to achieve balanced commutation; S03: Select the optimal duty ratio at different rotational speeds and torques through the fuzzy control algorithm to suppress torque ripple; Selecting the optimal duty ratio at different rotational speeds and torques through the fuzzy control algorithm includes: S31: Combine the rotational speed n and the torque T pairwise to obtain: When 0 < n ≤ A and 0 < T ≤ X, output y = N1L1; When 0 < n ≤ A and X < T ≤ Y, output y = N1L2; When 0 < n ≤ A and Y < T ≤ Z, output y = N1L3; When A < n ≤ B and 0 < T ≤ X, output y = N2L1; When A < n ≤ B and X < T ≤ Y, output y = N2L2; When A < n ≤ B and Y < T ≤ Z, output y = N2L3; When B < n ≤ C and 0 < T ≤ X, output y = N3L1; When B < n ≤ C and X < T ≤ Y, output y = N3L2; When B < n ≤ C and X < T ≤ Y, output y = N3L3; S32: Output the optimal duty ratio: When θ on ≤θ≤θ ov hour If the combination is N1L1, the output is: D 励 =τ 11 D 退 ＝α 11 Among them, D 励 is the excitation duty cycle, D 退 is the demagnetization duty cycle; If the combination is N1L2, then output: If the combination is N1L3, then output: If the combination is N2L1, then output: If the combination is N2L2, then output: Among them, the speed change ΔN = N-N0, where N is the actual speed and N0 is the rated speed. The torque change ΔT = T-T0, where T is the actual torque and T0 is the rated torque. The speeds in the three regions of the sinusoidal TSF waveform are A rpm, B rpm, and C rpm, and the corresponding torques are X n·m, Y n·m, and Z n·m. θ is the current rotor position, θ on is the opening angle of the k-phase winding; θ off The starting position angle for the conducting phase k to reduce the electromagnetic torque according to the rule set by TSF; θ ov is the angle of overlap of the currents of two adjacent phases; If the combination is N2L3, then output: If the combination is N3L1, then output: If the combination is N3L2, then output: If the combination is N3L3, then output: Among them, τ ij , α ij , β ij , δ ij , ω ij The optimal duty cycle obtained by debugging is i=1, 2, 3, j=1, 2, 3.

2. The fuzzy control-based switched reluctance motor torque distribution function segmented control method according to claim 1, characterized in that: The mathematical model of the switched reluctance motor in step S01 includes: Under the magnetic saturation state, the electromagnetic torque of the SRM linear model is: Where, T e , i, L, and θ are the electromagnetic torque, motor winding current, motor winding inductance, and rotor position angle, respectively; According to the mechanical law, the mechanical equation of the switched reluctance motor is: Where, T e 、T k ,m,J,ω,T L , F are the electromagnetic torque, the torque generated during the operation of the k-th phase winding, the number of phases of the motor, the moment of inertia of the motor, the angular velocity of the rotor, the load torque and the damping coefficient respectively; the angular velocity of the rotor is:

3. The fuzzy control-based switched reluctance motor torque distribution function segmented control method according to claim 1, characterized in that: The method for segmentally controlling the torque distribution function in step S02 includes: (1) Build a torque distribution control system to output the synthetic reference torque T required by the SR motor through the speed PI regulator ref According to the current rotor position θ, the desired torque T corresponding to A, B, and C is obtained from the torque distribution function. Aref 、T Bref 、T Cref , and the instantaneous torque tracking T is generated by the SR motor torque inverse model i(T, θ) ref The expected phase current i Aref 、i Bref 、i Cref , then the phase current is controlled to track the desired phase current through CCC controller or voltage PWM; (2) According to the control target of torque distribution, the distribution function is defined as f k (θ): Select the sine type as the torque distribution function, and its expression is: Where θ on is the opening angle of the k-phase winding; θ off The starting position angle for the conducting phase k to reduce the electromagnetic torque according to the rule set by TSF; θ ov is the overlapping angle of the adjacent two phase currents, , τ is the rotor period angle.

4. The fuzzy control-based switched reluctance motor torque distribution function segmented control method according to claim 1, characterized in that: The step S03 also includes adjusting the optimal duty cycle to minimize the torque ripple, making the actual torque waveform infinitely close to the expected torque waveform, and dividing the sinusoidal TSF waveform into the first overlapping area, namely θ on ≤θ≤θ ov , unidirectional conduction region, i.e. θ on +θ ov ≤θ≤θ off and the second overlapping region, i.e., θ off ≤θ≤θ off +θ ov ; In these three areas, the optimal duty cycle corresponding to the torque of X n·m, Yn·m, and Zn·m at the speed of Arpm, B rpm, and C rpm is obtained respectively.

5. The fuzzy control-based switched reluctance motor torque distribution function segmented control method according to claim 1, characterized in that: Step S03 also includes: When on +θ ov ≤θ≤θ off If the combination is N1L1, then output: D 励 ＝β 11 D 退 =d 11 If the combination is N1L2, then output: If the combination is N1L3, then output: If the combination is N2L1, then output: If the combination is N2L2, then output: If the combination is N2L3, then output: If the combination is N3L1, then output: If the combination is N3L2, then output: If the combination is N3L3, then output: When off ≤θ≤θ off +θ ov If the combination is N1L1, then output: D 退 =ω 11 If the combination is N1L2, then output: If the combination is N1L3, then output: If the combination is N2L1, then output: If the combination is N2L2, then output: If the combination is N2L3, then output: If the combination is N3L1, then output: If the combination is N3L2, then output: If the combination is N3L3, then output:

6. A fuzzy-controlled switched reluctance motor torque distribution function segmented control system, characterized in that: It includes: A switched reluctance motor mathematical model construction module that constructs the mathematical model of the switched reluctance motor; Torque distribution control system, which controls the sum of torques of different phases of a switched reluctance motor to be constant in segments through a torque distribution function. The torque distribution function aims at a constant synthetic instantaneous torque, distributes the desired torque of each phase at different positions through the torque distribution function, and controls the synthetic instantaneous torque to track the command torque output by a position closed-loop or speed closed-loop controller, and controls the change rate of the torque to achieve balanced commutation; Fuzzy control module, which selects the optimal duty cycle at different rotational speeds and torques through a fuzzy control algorithm to suppress torque ripple; Selecting the optimal duty cycle at different rotational speeds and torques through a fuzzy control algorithm includes: S31: Combining the rotational speed n and the torque T pairwise to obtain: When 0 < n ≤ A and 0 < T ≤ X, output y = N1L1; When 0 < n ≤ A and X < T ≤ Y, output y = N1L2; When 0 < n ≤ A and Y < T ≤ Z, output y = N1L3; When A < n ≤ B and 0 < T ≤ X, output y = N2L1; When A < n ≤ B and X < T ≤ Y, output y = N2L2; When A < n ≤ B and Y < T ≤ Z, output y = N2L3; When B < n ≤ C and 0 < T ≤ X, output y = N3L1; When B < n ≤ C and X < T ≤ Y, output y = N3L2; When B < n ≤ C and X < T ≤ Y, output y = N3L3; S32: Output the optimal duty cycle: When θ on ≤θ≤θ ov hour If the combination is N1L1, the output is: D 励 =τ 11 D 退 ＝α 11 Among them, D 励 is the excitation duty cycle, D 退 is the demagnetization duty cycle; If the combination is N1L2, then output: If the combination is N1L3, then output: If the combination is N2L1, then output: If the combination is N2L2, then output: Among them, the speed change ΔN = N-N0, N is the actual speed, N0 is the rated speed, the torque change ΔT = T-T0, T is the actual torque, T0 is the rated torque; the speeds in the three regions of the sinusoidal TSF waveform are A rpm, B rpm, and C rpm, and the corresponding torques are X n·m, Yn·m, and Zn·m. θ is the current rotor position, θ on is the opening angle of the k-phase winding; θ off The starting position angle for the conducting phase k to reduce the electromagnetic torque according to the rule set by TSF; θ ov is the angle of overlap of the currents of two adjacent phases; If the combination is N2L3, then output: If the combination is N3L1, then output: If the combination is N3L2, then output: If the combination is N3L3, then output: Among them, τ ij , α ij , β ij , δ ij , ω ij The optimal duty cycle obtained by debugging is i=1, 2, 3, j=1, 2, 3.

7. The fuzzy control-based switched reluctance motor torque distribution function segmented control system according to claim 6, characterized in that: The mathematical model of the switched reluctance motor includes: In the magnetic saturation state, the electromagnetic torque of the SRM linear model is: Where, T e , i, L, and θ are the electromagnetic torque, motor winding current, motor winding inductance, and rotor position angle, respectively; According to the mechanical law, the mechanical equation of the switched reluctance motor is: Where, T e , t k ,m,J,ω,T L , F are the electromagnetic torque, the torque generated during the operation of the k-th phase winding, the number of phases of the motor, the moment of inertia of the motor, the angular velocity of the rotor, the load torque and the damping coefficient respectively; the angular velocity of the rotor is:

8. The fuzzy control-based switched reluctance motor torque distribution function segmented control system according to claim 6, characterized in that: The torque distribution function segmented control method of the torque distribution control system includes: (1) The synthetic reference torque T required by the SR motor is output through the speed PI regulator ref According to the current rotor position θ, the desired torque T corresponding to A, B, and C is obtained from the torque distribution function. Aref 、T Bref 、T Cref , and the instantaneous torque tracking T is generated by the SR motor torque inverse model i(T, θ) ref The expected phase current i Aref 、i Bref 、i Cref , then the phase current is controlled to track the desired phase current through CCC controller or voltage PWM; (2) According to the control target of torque distribution, the distribution function is defined as f k (θ): Select the sine type as the torque distribution function, and its expression is: Where θ on is the opening angle of the k-phase winding; θ off The starting position angle for the conducting phase k to reduce the electromagnetic torque according to the rule set by TSF; θ ov is the overlapping angle of the adjacent two phase currents, τ is the rotor period angle.

9. The fuzzy control-based switched reluctance motor torque distribution function segmented control system according to claim 6, characterized in that: The fuzzy control module also includes debugging the optimal duty cycle to minimize the torque ripple, making the actual torque waveform infinitely close to the expected torque waveform, and dividing the sinusoidal TSF waveform into the first overlapping area, namely θ on ≤θ≤θ ov , unidirectional conduction region, i.e. θ on +θ ov ≤θ≤θ off and the second overlapping region, i.e., θ off ≤θ≤θ off +θ ov ; In these three areas, the optimal duty cycle corresponding to the torque of X n·m, Yn·m, and Zn·m at the speed of Arpm, B rpm, and C rpm is obtained respectively.

10. The fuzzy control-based switched reluctance motor torque distribution function segmented control system according to claim 6, characterized in that: The fuzzy control module also includes: on +θ ov ≤θ≤θ off If the combination is N1L1, then output: D 励 ＝β 11 D 退 =d 11 If the combination is N1L2, then output: If the combination is N1L3, then output: If the combination is N2L1, then output: If the combination is N2L2, then output: If the combination is N2L3, then output: If the combination is N3L1, then output: If the combination is N3L2, then output: If the combination is N3L3, then output: When off ≤θ≤θ off +θ ov If the combination is N1L1, then output: D 退 =ω 11 If the combination is N1L2, then output: If the combination is N1L3, then output: If the combination is N2L1, then output: If the combination is N2L2, then output: If the combination is N2L3, then output: If the combination is N3L1, then output: If the combination is N3L2, then output: If the combination is N3L3, then output:

Images