A method and system for controlling the conduction angle of a switched reluctance motor

Abstract

The present invention relates to a method and system for controlling the conduction angle of a switched reluctance motor. The method comprises the following steps: obtaining the actual motor speed and actual acceleration of the switched reluctance motor, calculating the winding peak current and the winding peak current angle; setting a given torque, and calculating the conduction adjustment angle of the switched reluctance motor based on the actual motor speed, given torque, winding peak current, and winding peak current angle; and compensating the motor conduction angle using the conduction adjustment angle. The present invention proposes a conduction angle adaptive technology that enables the motor to operate at its most efficient point. This technology eliminates the need for parameter measurement and adjustment for different motors, and allows for online adjustment of the conduction angle during operation.

Description

Technical Field

[0001] The present invention relates to the technical field of control of a switched reluctance motor, and in particular to a method and system for controlling a conduction angle of a switched reluctance motor. Background Art

[0002] The switched reluctance motor (SRM) is a new type of speed-regulating motor. Its speed regulation system combines the advantages of both DC and AC speed regulation systems, representing the latest generation of stepless speed regulation, following variable frequency drive systems and brushless DC motor speed regulation systems. It features a simple and robust structure, a wide speed regulation range, excellent speed regulation performance, high efficiency throughout the entire speed regulation range, and high system reliability. It primarily consists of four components: the SRM, a power converter, a controller, and a position sensor. The controller contains the power converter and control circuitry, while the position sensor is mounted at one end of the motor.

[0003] The switched reluctance motor (SRM) is a multivariable, strongly coupled, nonlinear control object. Its control parameters are four: the motor's set speed (or angular velocity ωr), the applied winding effective voltage Veq, the winding on-angle θon, and the winding off-angle θoff. ωr is the set value of the SRD system (switched reluctance motor speed control system). In current chopping control (CCC), Veq and θon are determined by the current chopping reference Ic. In single-pulse control (position angle control) (APC), Veq is completely determined by the winding on-angle. Therefore, the primary control variables of the SRD system are the winding on-angle θon and the winding off-angle θoff. For a given speed and torque (or power), the SRM has different combinations of θon and θoff that can meet the motor's output power requirements. This raises the question of optimal SRM switching, or optimal SRM angle control. The optimization objective is typically to maximize output power (or torque) or efficiency at a given speed. The range from θon to θoff represents the motor's conduction angle. Existing switched reluctance motor control technologies often use a fixed conduction angle, or one that has a fixed functional relationship with speed and torque, to optimize motor efficiency by controlling the motor's conduction voltage or current. Because the conduction angle is fixed or has a fixed functional relationship with speed and torque, the motor's conduction angle may not be at its optimal efficiency point under different speed and load conditions. Furthermore, the optimal efficiency point varies for different motors, making existing control technologies unable to meet efficiency optimization requirements. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a method and system for controlling the power-on angle of a switched reluctance motor.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned object is: a method for controlling the energization angle of a switched reluctance motor, comprising the following steps:

[0006] Obtain the actual motor speed and actual acceleration of the switched reluctance motor, and calculate the winding peak current and winding peak current angle;

[0007] Setting a given torque, and calculating a power-on adjustment angle of the switched reluctance motor according to the actual motor speed, the given torque, the winding peak current, and the winding peak current angle;

[0008] The power-on adjustment angle of the switched reluctance motor is calculated by the following formula:

[0009] ;

[0010] in, The power-on adjustment angle of the switched reluctance motor is is the angle optimization parameter, is the peak current of the winding, To shut off the current, is the adjustment angle of the winding peak current, is the adjustment angle for shutting off the current, Optimize the zero point for the angle, is a given torque, is the rated torque of the switched reluctance motor, is the rated speed of the switched reluctance motor, is the actual motor speed, is the winding peak current angle;

[0011] The power-on angle of the motor is compensated by utilizing the power-on adjustment angle.

[0012] The compensation of the motor power-on angle by using the power-on adjustment angle is specifically as follows:

[0013] ;

[0014] Where t represents the time, Indicates the motor power-on angle after compensation, Indicates the motor energization angle before compensation.

[0015] The angle optimization parameters Used to adjust the speed of angle optimization, the value range is 0≤ ≤1;

[0016] The angle optimizes the zero point The value range satisfies -1≤ ≤1.

[0017] A power-on angle control system for a switched reluctance motor, comprising:

[0018] The motor speed detection module is connected to the signal input port of the control module and is used to obtain the actual speed and actual acceleration of the switched reluctance motor;

[0019] The motor torque setting module is connected to the signal input port of the control module and is used to set the given torque;

[0020] The winding current detection module is connected to the signal input port of the control module and is used to calculate the winding peak current and the winding peak current angle;

[0021] a control module, configured to calculate a power-on adjustment angle of the switched reluctance motor according to the actual speed of the motor, the given torque, the winding peak current, and the winding peak current angle, and to compensate the motor power-on angle using the power-on adjustment angle;

[0022] The power-on adjustment angle of the switched reluctance motor is calculated by the following formula:

[0023] ;

[0024] in, The power-on adjustment angle of the switched reluctance motor is is the angle optimization parameter, is the peak current of the winding, To shut off the current, is the adjustment angle of the winding peak current, is the adjustment angle for shutting off the current, Optimize the zero point for the angle, is a given torque, is the rated torque of the switched reluctance motor, is the rated speed of the switched reluctance motor, is the actual motor speed, is the winding peak current angle.

[0025] The motor speed detection module includes a shading disk and a detection device;

[0026] The shading disk is connected to the rotating shaft of the switched reluctance motor and rotates concentrically with the rotating shaft at a constant speed;

[0027] The detection device is installed on the end of the motor shaft through a flat key.

[0028] The detection device includes at least three photoelectric detection switches, and the angle between the photoelectric detection switches is 11.25°.

[0029] The motor torque setting module sets the motor torque by the following formula:

[0030] ;

[0031] in, represents the motor torque, Indicates the output power of the motor, Indicates the output speed of the motor.

[0032] The winding current detection module includes a Hall current sensor, an operational amplifier and an isolated power supply.

[0033] The present invention has the following advantages and beneficial effects:

[0034] 1. The present invention proposes a power-on angle adaptive technology that can online calculate and adjust the motor power-on angle under different speeds and load conditions during motor operation, so that the motor runs at the most efficient point and optimizes the motor efficiency without requiring parameter measurement and adjustment for different motors.

[0035] 2. The present invention can save energy, reduce motor heat generation, increase motor life and reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Flow chart of the method of the present invention;

[0037] Figure 2 It is a structural diagram of the system of the present invention;

[0038] Figure 3 The current waveform diagram of the switched reluctance motor winding;

[0039] Figure 4 FIG1 is an installation structure diagram of a motor speed detection module in an embodiment of the present invention;

[0040] Figure 5 for Figure 4 Magnified view of the G region;

[0041] Figure 6 This is a schematic diagram of the installation position of the photoelectric detection switch;

[0042] Figure 7 This is the overall circuit diagram of the control module;

[0043] Figure 8 for Figure 7 Enlarged view of the left half;

[0044] Figure 9 for Figure 7 Enlarged view of the right half;

[0045] Figure 10 This is the circuit schematic diagram of the motor speed detection module. DETAILED DESCRIPTION

[0046] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0047] like Figure 1 As shown, a method for controlling the power-on angle of a switched reluctance motor includes the following steps: obtaining the actual motor speed of the switched reluctance motor, setting a given torque, and calculating the winding peak current and the winding peak current angle; calculating the power-on adjustment angle of the switched reluctance motor according to the actual motor speed, given torque, winding peak current and winding peak current angle; and compensating the motor power-on angle using the power-on adjustment angle.

[0048] Among them, the winding peak current and winding peak current angle are calculated as follows: take the two adjacent maximum winding peak currents in a measurement cycle 、 , combined with 、 The actual speed of the motor at this moment 、 and the actual acceleration of the motor 、 Calculate the peak winding current The winding peak current angle and winding peak current correspond.

[0049] The power-on adjustment angle of the switched reluctance motor is calculated by the following formula:

[0050] ;

[0051] in, The power-on adjustment angle of the switched reluctance motor is is the angle optimization parameter, is the peak current of the winding, To shut off the current, is the adjustment angle of the winding peak current, is the adjustment angle for shutting off the current, Optimize the zero point for the angle, is a given torque, is the rated torque of the switched reluctance motor, is the rated speed of the switched reluctance motor, is the actual motor speed, is the winding peak current angle;

[0052] Figure 3 The current waveform of the switched reluctance motor winding is combined with Figure 2A method for calculating the power-on angle of a switched reluctance motor is explained, and the power-on angle of the motor is compensated using the power-on adjustment angle, specifically:

[0053] ;

[0054] Where t represents the time, Indicates the motor power-on angle after compensation, Indicates the motor energization angle before compensation.

[0055] The angle optimization parameters The value range satisfies 0≤ ≤1, Used to adjust the speed of angle optimization. When K1 is 0, the adjustment is fastest. When it is 1, the adjustment is slowest. The angle optimization zero point The value range satisfies -1≤ ≤ 1. 、 After debugging and setting, the optimal value is obtained. 、 The adjustment method is a common method in this field and will not be described here.

[0056] like Figure 2 As shown, a power-on angle control system for a switched reluctance motor includes: a motor speed detection module connected to the signal input port of the control module, used to obtain the actual motor speed of the switched reluctance motor; a motor torque setting module connected to the signal input port of the control module, used to set a given torque; a winding current detection module connected to the signal input port of the control module, used to calculate the winding peak current and the winding peak current angle; a control module (such as Figure 7-9 As shown), it is used to calculate the power-on adjustment angle of the switched reluctance motor according to the actual speed of the motor, the given torque, the winding peak current and the winding peak current angle, and use the power-on adjustment angle to compensate the motor power-on angle.

[0057] like Figure 4-5 As shown, the motor speed detection module includes a shading disc 2-1 and a detection device 2-2; the shading disc 2-1 is connected to the shaft of the switched reluctance motor and rotates concentrically with the shaft at a constant speed; the detection device 2-2 is installed at the end of the motor shaft via a flat key. The detection device 2-2 includes at least three photoelectric detection switches, and the angle between the photoelectric detection switches is 11.25 degrees. Figure 6 The signal of the detection device 2-2 is transmitted differentially. The overall circuit schematic diagram of the motor speed detection module is as follows: Figure 10 shown.

[0058] The winding current detection module includes a Hall current sensor, an operational amplifier and an isolated power supply.

Claims

1. A method for controlling the conduction angle of a switched reluctance motor, characterized in that: The following steps are involved: Obtain the actual motor speed and actual acceleration of the switched reluctance motor, and calculate the winding peak current and winding peak current angle; Setting a given torque, and calculating a power-on adjustment angle of the switched reluctance motor according to the actual motor speed, the given torque, the winding peak current, and the winding peak current angle; The power-on adjustment angle of the switched reluctance motor is calculated by the following formula: Among them, Δθ is the power-on adjustment angle of the switched reluctance motor, K1 is the angle optimization parameter, I1 is the winding peak current, I2 is the shutdown current, ΔI1 is the adjustment angle of the winding peak current, ΔI2 is the adjustment angle of the shutdown current, K2 is the angle optimization zero point, T1 is the given torque, T n is the rated torque of the switched reluctance motor, V n is the rated speed of the switched reluctance motor, V1 is the actual speed of the motor, and θ1 is the winding peak current angle; The power-on angle of the motor is compensated by utilizing the power-on adjustment angle.

2. The method for controlling the conduction angle of a switched reluctance motor according to claim 1, wherein: The use of the power-on adjustment angle to compensate the motor power-on angle is specifically as follows: i 2t =Δθ*K1+θ 2(t-1) Among them, t represents the time, θ 2t Indicates the motor power-on angle after compensation, θ 2(t-1) Indicates the motor energization angle before compensation.

3. The method for controlling the conduction angle of a switched reluctance motor according to claim 2, wherein: The angle optimization parameter K1 is used to adjust the speed of angle optimization, and the value range satisfies 0≤K1≤1; The value range of the angle optimization zero point K2 satisfies -1≤K2≤1.

4. A switch reluctance motor power angle control system, characterized in that: include: The motor speed detection module is connected to the signal input port of the control module and is used to obtain the actual speed and actual acceleration of the switched reluctance motor; The motor torque setting module is connected to the signal input port of the control module and is used to set the given torque; The winding current detection module is connected to the signal input port of the control module and is used to calculate the winding peak current and the winding peak current angle; a control module, configured to calculate a power-on adjustment angle of the switched reluctance motor according to the actual speed of the motor, the given torque, the winding peak current, and the winding peak current angle, and to compensate the motor power-on angle using the power-on adjustment angle; The power-on adjustment angle of the switched reluctance motor is calculated by the following formula: Among them, Δθ is the power-on adjustment angle of the switched reluctance motor, K1 is the angle optimization parameter, I1 is the winding peak current, I2 is the shutdown current, ΔI1 is the adjustment angle of the winding peak current, ΔI2 is the adjustment angle of the shutdown current, K2 is the angle optimization zero point, T1 is the given torque, T n is the rated torque of the switched reluctance motor, V n is the rated speed of the switched reluctance motor, V1 is the actual speed of the motor, and θ1 is the peak current angle of the winding.

5. The switch reluctance motor power angle control system according to claim 4, characterized in that: The motor speed detection module includes a shading disk and a detection device; The shading disk is connected to the rotating shaft of the switched reluctance motor and rotates concentrically with the rotating shaft at a constant speed; the detection device is installed at the end of the motor shaft through a flat key.

6. The switch reluctance motor power angle control system according to claim 5, characterized in that: The detection device includes at least three photoelectric detection switches, and the angle between the photoelectric detection switches is 11.25°.

7. The switch reluctance motor power angle control system according to claim 4, characterized in that: The motor torque setting module sets the motor torque by the following formula: Wherein, T represents the motor torque, P represents the output power of the motor, and n represents the output speed of the motor.

8. The switch reluctance motor power angle control system according to claim 4, characterized in that: The winding current detection module includes a Hall current sensor, an operational amplifier and an isolated power supply.

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