KR20010094399A - Driver for Switched Reluctance Motor - Google Patents

Abstract

PURPOSE: A switched reluctance motor(SRM) driver is provided to prevent a counter torque which is generated when a phase current is eliminated by differentiating an excitation voltage and a demagnetization voltage without using an active device. CONSTITUTION: A DC(direct current) link capacitor(201) smoothes an inputted alternating current(AC) and supplies the smoothing direct current. An upper part and a lower part switching devices(203,204) are connected to the DC link capacitor(201) in parallel, perform on/off operations according to a driving signal of a switching driving unit outputting a gate driving signal in order to rotate on a motor to normal direction or reverse direction by a rotator position signal of an SRM(switched reluctance motor), and are connected to each other in serial. A motor winding(205) generates a torque according to the on/off operation of the upper part and lower part switching devices(203,204). Diodes(206,207) are connected to the motor winding(205) and capacitors(201,202). An additional power storage capacitor(202) is connected in parallel to an inductor(208), the upper part and lower part switching device(203,204), and the motor winding(205).

Description

SM Driver {Driver for Switched Reluctance Motor}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switched reluctance motor (SRM) driver, and more particularly, to an SM driver capable of quickly removing current by changing an excitation voltage and a potato voltage without using an active device.

Switched reluctance motor (SRM) 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, the SRM has both poles and rotors, and has a different number of poles. In particular, since the winding is wound only on the stator part, and there is no winding or permanent magnet in the rotor part, this simple structure can be regarded as the biggest feature of SRM.

Due to the structural features of SRM, it has significant advantages in terms of production and production. In addition, it has good starting characteristics and high torque like DC motors, but requires little maintenance and repair such as changing brushes regularly. Compared 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 detailed circuit diagram illustrating a structure of a conventional SRM driver.

Referring to FIG. 1, a conventional SRM driver is connected in parallel with the DC link capacitors 101 and 102 and the DC link capacitors 101 and 102 that smooth the input AC power and supply the smooth DC voltage. Series connected lower and lower switching elements 103 and 104, the upper and lower parts are turned on and off according to a driving 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 an electronic position signal. The first diode 106 connected between the motor winding 105 generating torque according to the on / off operation of the switching elements 103 and 104 and one end of the upper switching element 103 and one end of the lower switching element 104. ), And a second diode 107 connected between the other end of the upper switch and the other end of the lower switch.

Hereinafter, the operation of the conventional SRM 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 capacitors 101 and 102. The smoothed DC voltage is supplied to the motor winding 105.

That is, according to the position of the rotor (not shown) and the stator (not shown) of the SRM, the upper and lower switches 103 and 104 are turned on for a predetermined time, so that the first and second DC link capacitors 101 and 102 and the upper switching element are turned on. A current path is formed by the 103, the winding 105, and the lower switching element 104 to excite a voltage on the motor winding 305 to generate a magnetic force on the stator (not shown), thereby attracting the rotor (not shown). . As a result, the SRM rotates.

In this rotation, the upper and lower switches 103 and 104 are simultaneously turned off to remove phase currents applied to the windings through the first diode 106, the winding 105, the second diode 107, and the DC link capacitor 101. .

Hereinafter, the voltage excitation and demagnetization will be described in more detail.

First, when the commercial voltage AC 220V is applied from the outside, the DC link capacitors 101 and 102 are approximately DC 310V, and the excitation voltage is applied to the winding 105 when the upper and lower switching elements 103 and 104 are turned on. As a result, the phase current flowing in the motor winding 105 also gradually increases.

Subsequently, when the upper and lower switching elements 103 and 104 are turned off, the phase current is reduced by the potato voltage having the same magnitude as the voltage DC 310 that has been excited as described above.

However, in the conventional SRM driver as described above, the excitation voltage applying the current to the winding is equal to the demagnetization voltage to remove the excitation voltage, so that it takes a long time (t) to remove the current, and thus, the phase current remains in the motor winding for such a long time. If there is, there is a problem in the SRM in which high speed operation occurs due to reverse torque that causes the stator to pull the rotor backwards.

The present invention has been made to solve the above problems of the prior art, and provides an SM driver capable of high speed and high efficiency operation by quickly removing current by changing an excitation voltage and a potato voltage without using an active device. There is a purpose.

1 is a detailed circuit diagram showing the structure of a conventional SRM driver.

Figure 2 is a detailed circuit diagram showing the structure of the SRM driver of the present invention.

FIG. 3 is a diagram schematically showing a difference between a speed at which current is removed when a potato voltage is larger than an excitation voltage when the excitation voltage and the potato voltage are the same.

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

101,102,201 ... DC link capacitors 103,104,203,204 ... switching elements

105,205 ... motor winding 106,107,206,207 ... diode

202 ... Additional Power Accumulation Capacitor 208 ... Inductor

The SRM driver of the present invention for achieving the above object,

A DC link capacitor for supplying a DC voltage by smoothing an input power supply, a motor winding connected in parallel with the DC link capacitor, upper and lower switching elements connected in series with the motor winding, and one end of the upper switching element and the lower switching element. In the SM driver comprising a first diode connected between one end and a second diode connected between the other end of the upper switching element and the other end of the lower switching element,

And an inductor voltage connected to the upper switching element in series, the upper and lower switching elements, the motor winding, and an additional power storage capacitor connected in parallel with the inductor to different the excitation voltage and the potato voltage.

Preferably, the potato voltage is greater than the excitation voltage, characterized in that the magnitude of the potato voltage is adjusted to the size of the inductor.

3 is a detailed circuit diagram illustrating a structure of an SRM driver of the present invention.

Referring to FIG. 3, the SRM driver of the present invention is connected in parallel with the DC link capacitor 201 and the DC link capacitor 201 for smoothing an input AC power and supplying the smooth DC voltage. Series connected lower and lower switching elements 203 and 204 which are turned on and off according to 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 a rotor position signal of The motor winding 205 generates torque according to the on / off operation of the lower switching elements 203 and 204, the diodes 206 and 207, the inductor 208, and the motor windings 205 and the capacitors 201 and 202, respectively. The upper and lower switching elements 203 and 204, the motor winding 205, and the additional power storage capacitor 202 connected in parallel with the inductor 208.

Hereinafter, the operation of the SRM driver of the present invention configured as described above will be described in detail with reference to FIG. 3.

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 205 wound around the stator (not shown).

The upper and lower switching elements 203 and 204 are turned on for a predetermined time according to the position of the rotor (not shown) and the stator (not shown) of the SRM, so that the DC link capacitor 201, the upper switching element 203, and the motor are turned on. A current path is formed by the winding 205 and the lower switching element 204 to excite the voltage on the motor winding 205, and the phase current flows through the motor winding 205.

Thereafter, when the upper and lower switching elements 203 and 204 are turned off according to the position of the rotor and the stator of the SRM, the DC link capacitor 201, the first diode 206, and the motor winding are reversed as opposed to the turn on state. 205 and the second diode 207 and the inductor 208 form a current path to remove the phase current, and because of the characteristics of the inductor temporarily blocks the current (Blocking) because the constant voltage of the additional power storage capacitor 202 Will be charged.

Therefore, the voltage V2 of the additional power storage capacitor is as shown in Equation 1 below.

In Equation 1 Is the excitation voltage, Denotes the voltage charged by the current blocking of the inductor 208.

Thereafter, when the voltage of the additional power storage capacitor 202 is greater than or equal to a predetermined level, a current path is formed from the additional power storage capacitor 202 through the inductor 308 toward the DC link capacitor 201 to remove the current.

As described above, since the potato voltage is higher than the excitation voltage, the current can be removed more quickly.

In this case, when the potato voltage is greater than the excitation voltage, the current is removed quickly. However, when the potato voltage is too large, the devices have to be rated so that the potato voltage is adjusted to optimize the potato voltage.

In the present invention, the size of the inductor is adjusted so that the potato voltage is 30 to 50V higher than the excitation voltage.

FIG. 3 is a diagram schematically illustrating a difference between a speed at which current is removed when a potato voltage is larger than an excitation voltage when the excitation voltage and the potato voltage are the same.

As shown in FIG. 3, when the potato voltage is greater than the excitation voltage than when the excitation voltage and the potato voltage are the same, it can be seen that the time t 'when the phase current is removed is increased.

As described above, by changing the excitation voltage and the potato voltage without using the active element, it is possible to prevent reverse torque that may occur by quickly removing the phase current, and the motor can be operated at high speed and high efficiency.

In addition, it is effective in reducing costs by not using active elements.

Claims (3)

A DC link capacitor for supplying a DC voltage by smoothing an input power supply, a motor winding connected in parallel with the DC link capacitor, upper and lower switching elements connected in series with the motor windings, and one end of the upper switching element and the lower switching element. In the SM driver comprising a first diode connected between one end and a second diode connected between the other end of the upper switching element and the other end of the lower switching element, And an inductor connected in series with the upper switching element, the upper and lower switching elements, the motor winding, and an additional power accumulating capacitor connected in parallel with the inductor so that the excitation voltage and the potato voltage are different from each other. The method of claim 1, The SM driver, characterized in that the potato voltage is greater than the excitation voltage. The method of claim 1, SM voltage, characterized in that the voltage stored in the additional power storage capacitor is adjusted to the size of the inductor.