KR100354776B1 - Method for driving a Switched Reluctance Motor - Google Patents

Abstract

The present invention relates to a single-phase Switched Reluctance Motor driving method, comprising: (a) initial aligning a rotor and a stator with a power input; (b) having a predetermined free time after the rotor and stator are aligned as in step (a); (c) applying a breakaway pulse for initial rotation of the motor after a predetermined idle time; (d) increasing the rotational speed of the motor started through step (c) by receiving a signal through a first sensor and adjusting a PWM duty ratio; (e) comparing the rotational speed of the motor with a reference speed determined by the system; (f) controlling the rotational speed of the motor by dwell time by receiving a signal through the second sensor when the rotational speed of the motor becomes higher than the reference speed determined by the system as a result of the comparison in step (e); and ( g) Performing PWM operation by the first sensor when the rotational speed of the motor is less than the reference speed determined by the system as a result of the comparison in step (e); Characterized in that it comprises a.

In addition, according to the present invention as described above, it is possible to prevent the motor from starting due to abnormal parking, it is possible to minimize the switching loss of the device can be driven at high speed / high efficiency.

Description

Method for driving a Switched Reluctance Motor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single phase Switched Reluctance Motor (SRM) driving method. In particular, the present invention relates to a Single Phase Switched Reluctance Motor (SRM) driving method. It is about a method.

SLM is a type of motor that is currently being actively researched in Korea, and is classified as a special type of motor combined with a switching control device.

In addition, SM has both a stator and a rotor with a salient pole structure, and each has a different number of poles. In particular, since the winding is wound only on the stator part, and the rotor part does not have any type of winding or permanent magnet, this simple structure can be regarded as the biggest feature of SLM.

Due to the structural characteristics of SLM, it has significant advantages in terms of production and production. In addition, it has a good starting characteristic and a high torque like a DC motor. In comparison with the induction motor driven by the inverter, the structure of the driving device is simple, and it has excellent characteristics in many parts such as torque per unit volume, efficiency, and converter rating.

In addition, in the part requiring ultra-low speed operation of a wide variable speed range, the use field is increasing, especially in developed countries, because it shows very excellent characteristics.

1 is a block diagram schematically showing a conventional single-phase SM drive device.

Referring to FIG. 1, the conventional single-phase SM drive device includes a smoothing circuit unit 102 for smoothing an AC voltage applied from a commercial (AC) power source 101 to a DC voltage, and a voltage supplied from the smoothing circuit unit 102. And a Hall sensor 105 that receives a control signal from the microcomputer 106 and senses the position and speed of the motor driver 103 and the motor 104 to drive the motor 104, and outputs a signal to the microcomputer 106. It is composed of

Hereinafter, the operation of the conventional single-phase SM drive device configured as described above will be described in detail with reference to FIG. 1.

First, the smoothing circuit unit 102 smoothes the input commercial power supply 101. The voltage smoothed as described above is supplied to the motor driver 103, and the motor driver 103 supplies the voltage to the motor 104 according to the control signal of the microcomputer 106.

Thereafter, the hall sensor 105 detects the rotational speed and phase of the motor 104 and generates a signal, and the microcomputer 106 receives the signal generated by the hall sensor 105 as an input and outputs the motor driver 103. ) To control the voltage supplied from the motor driver 103 to the motor 104.

2 is a view showing the structure of a typical SM motor drive unit.

Referring to Figure 2, it will be described in detail the operation of the SM motor drive unit.

The SM motor drive unit is connected to the DC link capacitor 201 and the DC link capacitor 201 in parallel to smooth the input AC power and supply the smooth DC voltage, and the rotor 208 of the SM. Series connected lower and lower switching elements 202 and 203 turned on and off in accordance with a drive signal of a switch driver (not shown) for outputting a gate driving signal for rotating the motor in a forward or reverse direction according to the position signal, and the upper and lower switching. The first diode 204 connected between the motor winding 206 generating torque according to the on / off operation of the elements 202 and 203 and one end of the upper switching element 202 and one end of the lower switching element 203. And a second diode 205 connected between the other end of the upper switch and the other end of the lower switch.

Hereinafter, the operation of the SM motor driver having the above configuration will be described in detail.

First, when an AC voltage is supplied from the outside, it is smoothed to a DC voltage in the DC link capacitor 201. The smoothed DC voltage is supplied to the motor winding 206 by the switching operation of the upper and lower switching elements 202 and 203.

That is, the upper and lower switches 202 and 203 are turned on for a predetermined time according to the positions of the rotor 208 and the stator 207 of the SM, so that the DC link capacitor 201, the upper switching element 202, and the motor windings are turned on. A current path is formed by the 206 and the lower switching element 203 to excite the voltage on the motor winding 206 and generate a magnetic force in the stator 207 to attract the rotor 208. Accordingly, the SM is to rotate.

As the SM rotates and simultaneously turns off the upper and lower switches 202 and 203, the phase current applied to the windings causes the first diode 204, the motor winding 206, the second diode 205 and the DC link capacitor 201 to be turned off. To be removed.

As described above, the SLM drives the motor by supplying or blocking a voltage to the motor according to the on and off of the upper and lower switching elements 203 and 204 constituting the motor driving unit.

Here, the control signal applied to the upper and lower switching elements 202 and 203 detects the rotational speed and phase of the motor in the hall sensor and generates a signal as input to the microcomputer. Pulse width modulation (PWM) is performed to control the on and off operations of the upper and lower switching elements 202 and 203 according to the PWM duty ratio.

However, in the above-mentioned SM, which rotates at a high speed, when the upper and lower switching devices are controlled by adjusting the PWM duty ratio from low speed to high speed rotation, switching losses of the devices due to many switching are generated, and a lot of electromagnetic waves are generated. There is a problem.

3A to 3B are views illustrating normal parking positions and abnormal parking positions of SLM.

3A to 3B, in the SM, the N pole of the parking magnet 301a and the S pole of the magnet 304a fixed to the rotor 302a, parking for the next rotation when the motor stops, parking The S pole of the magnet 301a and the N pole of the magnet 304a fixedly installed on the rotor 302a correspond to each other and are parked by mutual attraction to be in a normal parking state.

However, as shown in FIG. 3B, when the rotor 302b is stopped, the N pole of the magnet fixed to the rotor 302b, the N pole of the parking magnet 301b, and the S pole of the magnet fixed to the rotor 302b, An abnormal parking state occurs in which the S poles of the parking magnet 301b correspond to each other and are parked by mutual repulsive forces.

When the rotor is located at the abnormal parking position as described above, even if a current is flowed to the stator for rotation of the motor, the rotor does not rotate or operates unstable.

The present invention has been made to solve the problems of the prior art as described above, and in particular, to provide a single-phase SM driving method capable of constituting a single-phase SM, minimizing the switching frequency of the device, and capable of stably driving the motor. The purpose is.

1 is a block diagram schematically showing a conventional single-phase SM drive device.

Figure 2 is a view showing in detail the structure of the motor driving unit of a typical single-phase SM.

3a to 3b are views for showing the normal parking position and abnormal parking position of the rotor of the single-phase SM.

Figure 4 is a block diagram schematically showing a single-phase SM drive of the present invention.

FIG. 5 is a diagram illustrating an inductance profile according to a phase change of a single phase SLM and a signal generated by a starting sensor and a driving sensor constituting the present invention.

Figure 6 is a flow chart for showing a single-phase SM driving process of the present invention.

7 is a graph illustrating a method of driving an SM of the present invention.

<Description of the symbols for the main parts of the drawings>

101,401 ... commercial power supply 102,402 ... smooth circuit

103,403 ... motor drive 104,404 ... motor

105 ... Hall sensor 106,407 ... Micom

201 ... Capacitor 202,203 ... Transistor

204,205 ... Diode 206 ... Motor winding

207,301a, 301b ... Stator 208,302a, 302b ... Rotor

303a, 303b ... parking magnet 304a, 304b ... magnet

405 ... Start sensor 406 ... Run sensor

SM drive method of the present invention for achieving the above object,

(a) initial aligning the rotor and stator with a power input;

(b) having a predetermined free time after the rotor and stator are aligned as in step (a);

(c) applying a breakaway pulse for initial rotation of the motor after a predetermined idle time;

(d) increasing the rotational speed of the motor started through step (c) by receiving a signal through a first sensor and adjusting a PWM duty ratio;

(e) comparing the rotational speed of the motor with a reference speed determined by the system: and (f) a signal through the second sensor when the rotational speed of the motor becomes higher than the reference speed determined by the system as a result of the comparison of step (e) Controlling the rotational speed of the motor by the dwell time received; ( g) PWM operation by the first sensor when the rotational speed of the motor is less than the reference speed determined by the system as a result of the comparison of the step (e); More preferably, (h) after step (f), turning off the power, and determining whether the power is turned on again; (i) of step (h) Determining whether the motor is stopped if the power is turned on; (j) if the motor is not stopped as a result of the determination of step (i), feeding back to step (d) to repeat the steps. It further comprises.

Figure 4 is a block diagram schematically showing a single phase SM drive of the present invention.

Referring to FIG. 4, the single-phase SM driving device of the present invention is provided with a smoothing circuit section 402 and a smoothing circuit section 402 for smoothing an AC voltage applied from a commercial (AC) power supply 401 to a DC voltage. A start sensor that senses the rotational speed and phase of the motor driver 403 and the motor 404 for driving the motor 404 by receiving a control signal from the voltage and the microcomputer 407 and outputs a signal to the microcomputer 407. 405 and driving sensor 406.

Hereinafter, the operation of the single-phase SM driving device of the present invention configured as described above with reference to FIG. 4 will be described in detail.

First, the smoothing circuit unit 402 smoothes the input commercial power supply 401. The smoothed voltage is supplied to the motor driver 403, and the motor driver 403 supplies the voltage to the motor 404 according to the control signal of the microcomputer 406.

Thereafter, the starting sensor 405 and the driving sensor 406 detect the rotational speed and phase of the motor 404 to generate a signal.

At this time, the starting sensor 405 and the driving sensor 406 detect different phases of the rotor. More specifically, the driving sensor 406 detects a phase ahead of the starting sensor 405.

As described above, the signals generated by the starting sensor 405 and the driving sensor 406 are input to the microcomputer 407. When the motor is initially started, the motor driving unit selects the signals generated by the starting sensor 405 from the microcomputer. Generate a control signal for controlling 403.

When the speed of the motor is equal to or higher than the reference speed determined by the system, a signal generated by the driving sensor 406 is selected and input, and a control signal for controlling the motor driving unit 403 is output.

FIG. 5 is a diagram illustrating an inductance change according to a phase change of SLM and a signal generated by sensing by a start sensor and a driving sensor of the present invention.

Referring to FIG. 5, when the protrusion of the rotor of the SM and the protrusion of the stator are exactly misaligned (when misaligned), the inductance is the smallest. At the time when the inductance starts to increase, the motor driver supplies the voltage to the SM. Current flows through the motor windings.

The start sensor employed in the SM drive of the present invention generates a signal by detecting a phase at which the inductance starts to increase, and the driving sensor detects a phase ahead of the phase detected by the start sensor.

As described above, the starting sensor and the driving sensor detect a rotational speed and phase of the motor, and then generate a signal and send the signal to the microcomputer. In the microcomputer, one of the generated signals of the two sensors input according to the rotational speed of the motor is selected and input. The control signal is outputted to the motor driving unit.

FIG. 6 is a flowchart illustrating a process of driving the single-phase SM driving device of the present invention configured as shown in FIG. 4.

Hereinafter, referring to FIG. 6, the single-phase SM driving method of the present invention will be described in detail.

First, when the power is turned on to drive the single-phase SM (step 601), the initial alignment is performed (step 602). The reason for this initial alignment is that the torque is zero due to the characteristics of the magnet fixed to the rotor of SLM. That is, to solve the problem of abnormal parking by repulsive force between the magnets fixed to the parking magnet and the rotor as mentioned in the conventional problem.

In the initial alignment method, a large number of small pulses are output to the upper and lower switching elements of the motor driving unit to temporarily apply current to the motor windings.

After the initial alignment is completed as in step 602, a certain amount of time is allowed to leave the rotor at the normal parking position as shown in FIG. 3B (step 603). In the present invention, it is assumed that the blank time is about 1 second.

When the rotor goes to the normal parking position through the above steps, a large pulse (escape pulse), that is, a large amount of current is applied to the motor winding so that the rotor can escape from the parking position (step 604).

As described above, when the release pulse is applied to the motor driving unit to generate the instantaneous torque, the rotor starts to rotate, and the rotation speed of the rotor is gradually increased by performing a small duty pulse width modulation (PWM). Increasing the duty ratio of the motor increases the rotational speed of the rotor (step 605).

The PWM duty ratio is determined by the following equation.

In Equation 1 The duty ratio, Is the time of the on period of the upper and lower switching elements, Denotes the off section time of the upper and lower switching elements. As shown in Equation 1, the duty ratio is a numerator value because the denominator is constant. Determined by the value.

Therefore, increasing the duty ratio means that the on time of the upper and lower switching elements of the motor driver having the configuration as shown in FIG. 2 is increased, which means that the rotor rotates faster by flowing more current to the motor windings.

In addition, the PWM is performed in a section from a rising edge to a falling edge of the start sensor.

Then, using the start sensor, the rotational speed and phase of the motor are detected and compared with the reference speed determined by the system (step 606).

When the detected rotational speed of the motor is faster than the reference speed determined by the system as a result of the comparison of step 606, the dwell time control is performed by moving the reference of the current from the start sensor to the operation sensor. If it is below the reference speed, continue the process of adjusting the PWM duty ratio.

The dwell time control as described above refers to the fact that the current flows at a time during the predetermined time defined by the microcomputer, instead of turning on and off the switching elements according to the duty ratio as in the PWM. The number of switching of the switching elements is significantly reduced.

Here, the dwell time control is a value previously read and is used when the next value is predictable. The reason why the current reference is moved from the start sensor to the operation sensor during the dwell time control is when the commutation reference is the start sensor. Because the RPM changes a lot, it is difficult to predict the next value with the previously read value.

Then, when the external power is turned off (step 608), it is determined whether the external power is turned on again (step 609).

If the external power is not turned on as a result of the determination of step 609, the driving of the SLM ends (step 611). If the external power is turned on again as a result of the determination of step 609, it is determined whether the motor is rotating (step 610). ).

If the motor is stopped as a result of the determination of step 610, the process is fed back to the step 602, and the steps are repeated from the initial alignment. If the motor is not stopped, the process of steps 602, 603, and 604 is not necessary. Thus, the above steps are repeated.

FIG. 7 is a graph illustrating a method of driving an SM of the present invention as described above. FIG.

As described above, the single-phase SM driving method of the present invention prevents the motor from starting due to abnormal parking in the single-phase SM, minimizes switching loss of the device, and operates at high speed / high efficiency. have.

Claims (5)

(a) initial aligning the rotor and stator with a power input; (b) having a predetermined free time after the rotor and stator are aligned as in step (a); (c) applying a breakaway pulse for initial rotation of the motor after a predetermined idle time; (d) increasing the rotational speed of the motor started through step (c) by receiving a signal through a first sensor and adjusting a PWM duty ratio; (e) comparing the rotational speed of the motor with a reference speed determined by the system: and (f) controlling the rotational speed of the motor by dwell time by receiving a signal through the second sensor when the rotational speed of the motor becomes higher than the reference speed determined by the system as a result of the comparison in step (e); ( g) PWM operation by the first sensor when the rotational speed of the motor is less than the reference speed determined by the system as a result of the comparison of step (e); Single-phase SM drive method comprising a. The method of claim 1, (h) after step (f), turning off the power and determining whether the power is turned on again; (i) determining whether the motor is stopped if the power is turned on as a result of the determination of step (h); and (j) if the motor is not stopped as a result of the determination of step (i), feeding back to the step (d) and repeatedly performing the steps. The method of claim 2, And as a result of the determination of step (i), if the motor is stopped, feeding back to step (a) and repeatedly performing the steps. The method of claim 1, The initial alignment is a single phase SM drive method, characterized in that for applying a small number of pulses to the motor drive so that the current flowing in the motor winding is not excessive. The method of claim 1, If the rotational speed of the motor is slower than the reference speed determined by the system as a result of the comparison of the step (e), the single-phase SR is controlled by continuously receiving the signal of the first sensor and adjusting the PWM duty ratio. Em driving method.