JPH02142397A - Driver for variable reluctance motor - Google Patents

Abstract

PURPOSE:To enable stopping rotation completely by conducting a braking action at the time of a power failure and by supplying power from a capacitor. CONSTITUTION:A four-phase variable reluctance motor SRM is driven via a conducting circuit 12 by a driving power supply 2. A control circuit 14 detects a rotor position by means of a pole encoder 8 and a rotary encoder 10, gives a command to the conducting circuit 12 accordingly, and controls the excitation timing of each phase winding La-Ld. At the time of a power failure, a brake control circuit 16, instead of the control circuit 14, gives a command to the conducting circuit 12 according to the command of a power-failure detector circuit 20 to conduct a brake control. Also, power stored in the capacitor 32 of the driving power supply 2 is used as the power at the time of the power failure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a drive device for a variable reluctance motor.

[Prior Art] A variable reluctance motor (hereinafter referred to as an SR motor) loses reluctance (hereinafter referred to as an SR motor) because its stator and rotor are made of iron when the power supply is stopped due to a power outage or the like during operation.
magnetic resistance) disappears.

[Problems to be Solved by the Invention] Therefore, the SR motor continues to rotate due to load inertia, and enters a so-called free run state. However, conventional drive devices are not equipped with a means to stop the SR motor in the event of a power outage, and the only option is to wait for the SR motor to stop due to friction torque or the like.

Therefore, the present invention was made with the intention of providing a drive device for a variable reluctance motor that can be braked when the power is cut off.

[Means for Solving the Problems] The gist of the present invention is to provide a DC power source that rectifies an AC input from an AC power source, smooths it using a power storage means, and outputs a DC; energizing means for energizing each phase winding; control means for driving or braking the variable reluctance motor by controlling the timing of energization of the energizing means; and energization of the phase winding by the energizing means. In the drive device for a variable reluctance motor, the variable reluctance motor drive device includes power regeneration means that regenerates magnetic energy stored in the phase winding as a charge to the power storage means, and detects that the power supply from the AC power supply has stopped. means, voltage conversion means for outputting a predetermined DC voltage to the control means when the detection means detects a stoppage of power supply; and an operation of the control means when the detection means detects a stoppage of power supply. A variable reluctance motor drive device is provided, characterized in that it is provided with a switching means for switching the operation to a braking operation.

[Function] According to the above configuration of the present invention, the power storage means is always charged when the AC power supply is supplying power, so even if the power supply from the AC power supply is stopped, the power storage means has a predetermined charge. A large amount of power is stored. Therefore, when the supply of AC power is stopped, the energizing means can energize the phase windings from the DC power source, and the voltage converting means can generate a predetermined DC voltage from the DC power source.

Therefore, when the detection means detects that the power supply from the AC power supply has stopped, the switching means switches the operation of the control means to the braking operation, and the voltage conversion means outputs the DC voltage to the control means. Then, the control means becomes capable of braking operation, and thus controls the timing of energization of the energization means to brake the variable reluctance motor.

When the energizing means cuts off the current to the phase windings during the '#J movement, the power regeneration means regenerates the magnetic energy accumulated in the phase windings into the electricity storage means as a charge, so the electricity storage means is charged even during braking. be done. Therefore, the energizing means can continue to energize the phase windings, and the voltage converting means can also continue to output DC voltage to the control means, so braking continues and the rotation of the variable reluctance motor stops.

[Example code] An embodiment of the present invention will be described based on the drawings.

As shown in FIG. 1, a drive device 1 for a four-phase variable reluctance motor (hereinafter referred to as an SR motor) includes a drive power source 2 that generates direct current for driving the SR motor, and supplies power to each part of the drive device. A control power source 4 that converts the voltage of the drive power source 2 into a predetermined voltage and outputs it, a well-known DC-DC converter 6 as a voltage conversion means, and a magnetic pole position encoder attached to the rotating shaft of the SR motor SRM. 8 and a well-known rotary encoder 10, an energizing circuit 12 serving as energizing means for energizing each phase winding La, Lb, Lc, and Ld from the drive power source 2, and a control circuit 14 controlling the energizing timing of the energizing circuit 12. , a brake control circuit 16 that controls the energization timing of the energization circuit 12 to brake the SR motor SRM in place of the control circuit 14 when the power supply from the AC power source AC stops (hereinafter referred to as a power outage); and a control circuit in the event of a power outage. The brake control circuit 16 is used instead of the energizing circuit 1 in place of the brake control circuit 14.
2, and a power failure detection circuit 20 as a detection means for detecting a power failure.

Note that the control circuit 14 and the brake control circuit 16 correspond to eight control means.

The drive power source 2 rectifies the alternating current input from the alternating current power source AC in a rectifier circuit 30, and then converts it into a capacitor 3 as a power storage means.
2 to create a direct current, which is output to the energizing circuit 12.

As shown in FIG. 2, the control power source 4 generates a DC voltage Vcc of a predetermined magnitude using a well-known voltage regulator 34 and outputs it to each part of the drive device.

When the thyristor 36 is turned on by a power failure detection signal Sig from a power failure detection circuit 20 (described later), the DC-DC converter 6 is supplied with power from the drive power source 2 and creates a voltage Vcc of a predetermined size. The output end of the DC-DC converter 6 is connected to the control power supply 4 via a diode Dp for preventing backflow.
It is connected to the output end of the control power supply 4 and outputs the voltage Vcc to each part of the above-mentioned drive device in place of the control power supply 4 during a power outage.

The magnetic pole position encoder 8 is made up of a rotating disk Di and a photointerrupter Pi, which are attached to the rotating shaft of the SR motor SRM and have a shape that is almost the same as the rotor cross section, and as shown in FIG.
Ratio bO% on/off signal, ■Magnetic pole position detection signal that turns off when the rotor (path shown) of the mouth-chip SR motor SRM is in a position directly facing the stator (path shown) and turns on when the rotor is in the center of the adjacent stators Output Sp.

The energizing circuit 12 is connected to the SR motor SR as shown in FIG.
Phase windings La and Lb are provided for each phase (A phase, B phase, C phase, D phase) of M, and are connected from the driving power source 2 to the phase windings La and Lb.

Drive circuit 40 a + 40 that supplies current to Lc and Ld
b.

40c, 40d and a power consumption circuit 42.

Each of the drive circuits 40a to 40d includes two field effect transistors FETa and FETb, their gate drive circuits Dra and Drb, and two regeneration diodes Da and which regenerate the phase winding current to the capacitor 32 when the current is cut off. Db. The power consumption circuit 42 includes a power consumption resistor R, a field effect transistor fet, and its gate drive circuit dr. When the field effect transistor fet is turned on, a phase winding current flows through the resistor R and power is consumed.

Note that the regeneration diodes Da and Db correspond to power regeneration means.

The control circuit 14 is connected to the energizing circuit 12 via the connection switching circuit 1 when power is supplied from the alternating current power supply AC (hereinafter referred to as normal time), and the control circuit 14 is connected to the energizing circuit 12 via the connection switching circuit 1.
The signal distribution circuit (
Magnetic pole position detection signal Spa for each phase created by
, Spb, Spc, Spd and the rotation angle detection signal Sr input from the rotary encoder 10, energization signals Ta, Tb, Tc, and Td that determine the energization timing of the energization circuit 12 are created, and are detected by the current detector CT. When the phase winding current exceeds a predetermined dark value current, the energization signal Ta-T
d is intermittent by a well-known chopper operation and output to the connection switching circuit 1.

Furthermore, the control circuit 14 is equipped with an overvoltage prevention circuit (the circuit shown in the figure) composed of a comparator, etc., which prevents the phase winding current regenerated during chopping from increasing and the voltage of the driving power source 2 to exceed a predetermined value. limiter signal LA that turns on the field effect transistor fet of the power consumption circuit 42 when
is output to the connection switching circuit 1 to prevent the voltage applied to the capacitor 32 and the field effect transistors FETa and FETb from exceeding their withstand voltages.

As shown in FIG. 5, the brake control circuit 16 includes four brake signal generation circuits 50a, 50b, 50c, and 50d each consisting of a comparator CP and a logical AND NOT circuit NAND.
and an overvoltage prevention circuit 52.

As shown in FIG. 6, the brake signal generation circuits 50a to 50d generate brake signals Ba and Bb that control the energization timing in place of the control circuit 14 during a power outage.

Bc and Bcl are created and output to the connection switching circuit on the 1st.

That is, based on the magnetic pole position detection signals Spa, Spb, Spc, and Spd for each phase created in the same manner as the control circuit 14, the area where the rotor separates from the position where it directly faces the stator, that is, the phase winding La-Ld is detected. The phase winding current detection signals V ia and V ib input from the current detector CT in the region where the inductance of V ia and V ib decrease.

V ic and V id are the reference voltage Ref (dark value type'/
When the voltage is less than the voltage corresponding to the reference voltage R, the drive circuits 40a to 40d are instructed to conduct electricity,
When the value is equal to or higher than ef, a brake signal Ba-Bd is generated which instructs to stop the energization. Further, the overvoltage prevention circuit 52 prevents the voltage signal VR corresponding to the voltage of the drive power supply 2 during chopping (the voltage signal input from which voltage dividing point of the voltage detection resistors R1 and R2) from exceeding a predetermined voltage level Vlim. When this happens, a limiter signal LB that turns on the fet of the power consumption circuit 42 is output to the connection switching circuit 18.

The connection switching circuit 18 includes a well-known analog switch 60, as shown in FIG.
When a power outage detection signal Sig is input from , the brake control circuit 16 is connected to the energizing circuit 12 instead of the control circuit 14 .

As shown in FIG. 8, the power outage detection circuit 20 includes a transformer 70 that transforms AC voltage, a comparator 72, a counter circuit 74, a latch circuit 76, and a clock circuit 7 as main parts. There is.

First, the comparator 72 determines whether the secondary output Vout of the transformer 70 is the reference voltage V re
When the peak detection signal Sep exceeds f, a peak detection signal Sep having a Lo sound level is output. The peak detection signal Sep is shaped into a pulse signal P by the waveform shaping circuit 80 and input to the counter circuit 74 . When the pulse signal P is input, the counter circuit 74 receives the clock pulse P input from the clock circuit 78.
Start counting CLK. The counter circuit 74 is
After counting a predetermined number of clock pulses P CLK, a carry signal S cry is output to the latch circuit 76, but before that, the next pulse signal P is input, so that it is reset. In other words, the carry signal 5cry is not output under normal conditions. Further, since the counter circuit 74 counts up for a predetermined period of time, an instantaneous power outage or voltage drop shorter than that period is not detected as a power outage.

However, as shown in column (■) in FIG. 9, in the event of a power outage, the peak detection interval is extended, during which time the counter circuit 74 counts up and outputs a carry signal Scry to the latch circuit 76. Then, the output signal of the latch circuit 76, that is, the power failure detection signal Sig becomes high level. In this way, the power failure is detected and the power failure detection signal Sig is output to the connection switching circuit 1 and the thyristor 36.

Next, the operation of the drive device 1 will be explained.

When the SR motor SRM is normally driven, current flows from the capacitor 32 to the phase windings La-Ld, but since the rectifier circuit 30 supplies charge and is constantly charged, the capacitor 32 receives a predetermined amount of power. It is stored.

On the other hand, during the floating type, the connection switching circuit 1 connects the brake control circuit 16 to the energizing circuit 1 instead of the control circuit 14.

Then, instead of the control unit power source 4, a DC-DC converter 6 uses the capacitor 32 as a power source to generate a predetermined DC voltage V.
cc is output to each part of the drive device.

Therefore, as shown in FIG. 6, the brake control circuit 16 operates '8! Based on the pole position detection signals 5pa-5pd, the brake signal Ba-
When Bd is output to the connection switching circuit 18, the connection switching circuit 1
On the other hand, gate drive signals Ga to Gd are applied to each drive circuit 50a to 50.
Output to 0d.

This applies braking to the rotation of the SR motor SRM. In this braking process, since current is applied in a region where the rate of change of the phase winding inductance is negative, an induced electromotive force is generated in a direction in which the phase winding current continues to flow. That is, the phase winding La-L
A voltage V expressed by the following equation is applied to d.

V=LXd I/d t=Vc+I XdL/dθXω
(However, L is the inductance of the phase winding, ■ is the phase winding current, Vc is the voltage of the capacitor, θ is the rotation angle of the rotor, ω is the angular velocity, I X d L/dθ×ω is the SR motor SRM
For this reason, the phase winding current rises sharply and the dark value current Ir
However, at this time, the comparator CP of the brake control i output circuit 1G operates, a well-known chopper operation is performed, and the phase winding current is suppressed to the dark value current 1 ref. During this chopper operation process, the capacitor 32 is connected to the phase winding La.
When -Lb is energized, a part of the electric power stored in the capacitor 32 is stored in the phase winding La-Lb as magnetic energy. However, during braking, the stator of the SR motor rotates against reluctance (magnetic resistance), so the load inertia gradually decreases, and the phase winding La
Magnetic energy is accumulated in +L,b. That is, the magnetic energy accumulated in the phase windings La to Lb increases. That is, the magnetic energy accumulated in the phase windings La-Lb is expressed by the following equation.

1/2L I2=VcI +1/2I2XdL/dθ
×ω (However, 1/2LI2 is the magnetic energy stored in the phase winding, VcI is the power supplied from the capacitor 32, and 1/2I"XdL/dθω is the magnetic energy generated by power generation.) This increased magnetic energy At the time of interruption, the capacitor 32 is converted into electric charge via the regeneration diodes Da and Db.
is stored in Therefore, the charge accumulated in the capacitor 32 increases compared to before energization. This charge is then used for the next energization.

In this way, the power required for braking the SR Momo-SRM is secured, so the drive device 1 can continue to brake the SR Momo-SRM, and the rotation of the SR Momo-SRM is completely stopped.

Also, as mentioned above, during the chopper operation process, the capacitor 32
As the electric charge continues to increase and the voltage may exceed the withstand voltage, when the voltage of the capacitor 32 exceeds a predetermined level, the electric field effect of the power consumption circuit 42 is reduced by the limiter signal LB of the overvoltage prevention circuit 52 of the brake control circuit 16. The transistor fet is turned on, and part of the phase winding current flows through the resistor R and is consumed as heat.

As explained above, in this drive device 1, the SR at the time of power outage is
During the braking process of the MOMO-SRM, the capacitor 32 can supply sufficient power to the drive circuits 40a-40d and the DC-DC converter 6, so the SR MOMO-S
RM can be completely stopped. Therefore, it is possible to prevent the SR MOMO-SRM from free running during a power outage.

In addition, since the capacitor 32 is charged by a portion of the electric power generated by the load inertia of the SR Momo-SRM during the braking process, there is no need to provide a backup power source in case of a power outage.

Furthermore, the power outage detection circuit 20 can detect a power outage before the power supply voltage drops significantly due to a power outage, and does not detect an instantaneous power outage or voltage drop as a power outage, so the SR Momo-SRM can be safely and reliably stopped. At the same time, the power outage detection circuit 20 operates other than during a power outage, and the SR Momo-S
There is no need to stop RM.

[Effects of the Invention] As described above in detail, in the variable reluctance motor drive device of the present invention, the switching means switches the operation of the control means to the braking operation during a power outage, and the voltage conversion means outputs a DC voltage to the control means. Therefore, the control means can brake the variable reluctance motor by controlling the energization timing of the energization means.

When the energizing means cuts off the current to the phase windings during braking, the power regeneration means regenerates the magnetic energy accumulated in the phase windings into the power storage means, so that the power storage means is charged even during braking. Ru. Therefore, the energizing means can continue to energize the phase windings, and the voltage converting means can also continue to output DC voltage to the control means, so the braking operation is continued and the rotation of the variable reluctance motor is completely stopped. be able to.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the variable reluctance motor drive device of the embodiment, Fig. 2 is an electric circuit diagram showing the control power supply and DC-DC converter, and Fig. 3 is the inductance change rate and magnetic pole position of the phase winding. Explanatory diagram showing detection signals, 4th
Figure 5 is an electric circuit diagram showing the energizing circuit, Figure 5 is an electric circuit diagram of the brake control circuit, Figure 6 is an explanatory diagram showing the inductance change rate of the phase windings, the excitation current of the phase windings, and the gate drive signal. FIG. 7 is a block diagram showing a connection switching circuit, FIG. 8 is an electric circuit diagram showing a power outage detection circuit, and FIG. 9 is an explanatory diagram showing a peak detection signal, a detection signal, etc. in the power outage detection circuit. 1... Variable reluctance smorph drive device 2... Drive power source 4... Control power source 6... DC-D
C converter 12... energizing circuit 14...-controller circuit 16
...Brake control circuit 18...Connection switching circuit 20...-Power failure detection circuit 3
2... Capacitor AC... AC power supply Da, Db... Regeneration diode FETa, FETb... Field effect transistor La~
Lb... Phase winding agent Patent attorney Tsutomu Sadate (and 2 other people) Figure 1 Figure 2 Figure 3 Acceleration Figure 6 Brake, Kuto, Kumuto, To, )kuQl) , 1 phrase, 1 Fig. 9 (I> (n) Detection signal 57g -11111-'-

Claims (1)

[Scope of Claims] A DC power supply that rectifies AC input from an AC power supply and smoothes it using a power storage means to output DC; and an energizing means that energizes each phase winding of a variable reluctance motor from the DC power supply; a control means for driving or braking the variable reluctance motor by controlling the timing of energization of the energization means; and when the energization means interrupts energization to the phase winding;
A drive device for a variable reluctance motor, comprising: power regeneration means for regenerating magnetic energy accumulated in the phase winding into charge in the power storage means; a detection means for detecting that power supply from the AC power supply has stopped; , voltage conversion means for outputting a predetermined DC voltage to the control means when the detection means detects a stop in the power supply; and when the detection means detects a stop in the power supply, brakes the operation of the control means. A driving device for a variable reluctance motor, comprising: a switching means for switching to an operation; and a variable reluctance motor drive device.