JPH0412794Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a power supply device that controls a three-phase induction motor with single-phase alternating current using an inverter circuit, and particularly relates to the circuit configuration of the rectifier section. .

(b) Prior Art In general, conventional techniques include those described in Japanese Patent Application Laid-Open No. 50-35626 and Japanese Patent Application Laid-open No. 59-67873. In the former case, the AC voltage supplied to the diode bridge is 200
A switch was operated depending on whether it was [V] or 100 [V]. Also, in the latter case, the AC voltage supplied to the diode bridge is
It automatically judged whether it was 200 [V] or 100 [V] and operated the switch.

(c) Problems to be solved by the invention In the former conventional technology, there was a high possibility that the switch would be operated by mistake after the power supply device (or device) was installed. In other words, if an AC of 200 [V] is applied when a voltage doubler rectifier circuit is configured, a voltage of 400 [V] will be applied to the smoothing capacitor, inverter circuit, and induction motor, causing damage to each element. The problem is that when a normal rectifier circuit is configured and an AC of 100 [V] is applied, only a low voltage of 100 [V] is applied to the inverter circuit and induction motor, and the low voltage causes an excess. There was a problem in that the current flow caused each element to burn out.

In the latter conventional technology, when the 200 [V]/100 [V] switching circuit fails, the same problem as the former conventional technology occurs.

Generally, this setting of 200 [V]/100 [V] does not need to be done again once the power supply is installed, and when considering the safety of the power supply or equipment, the setting of 200 [V]/100 [V] It was essential that [V] be constructed so that it could not be easily switched.

Further, such a problem is particularly problematic when starting a motor that requires a large amount of current at the time of starting, such as an induction motor, but it is not a big problem when the load is light because the inrush current is small when energized. Similarly, when an induction motor is used as a load, there is a problem in that if the ripple in the DC power supplied to the inverter circuit is large, the rotating machine of the motor wobbles and vibrations occur. In the rectifying and smoothing circuit shown in both conventional techniques, when configuring a normal rectifier circuit, the two capacitors used for voltage doubler rectification are connected in series, so the required amount of smoothing capacitors is halved. There was a problem that the ripple of DC power increased.

To solve these problems, this invention has 200
It has a configuration that does not allow easy switching between [V] and 100 [V], and even at 200 [V] and 100 [V], the ripple of the power supplied to the induction motor is always suppressed to a predetermined value or less, thereby reducing vibration noise. The present invention provides a power supply device for an induction motor that is suppressed.

(d) Means for Solving the Problems The power supply device of the present invention has a diode bridge with a single-phase alternating current supplied between its input terminals and a first
A capacitor and a second capacitor are connected in series, a third capacitor is connected between these output terminals, and a third capacitor is connected between the connection point of the first capacitor and the second capacitor and one of the input terminals. A jumper wire is connected, and an inverter circuit that converts DC power into three-phase AC power is connected to both ends of the third capacitor, and the three-phase AC power output from this inverter circuit is supplied to the induction motor, and the single-phase The jumper wire is cut or removed when the AC voltage is doubled.

(E) Effect In the power supply device configured in this way, the single-phase AC power supplied to the diode bridge is 200 [V].
Or, even if the voltage is 100 [V], depending on whether you remove the jumper wire or leave it as is, the same voltage of DC power will always be supplied to the inverter circuit, and the voltage supplied to the motor will also be constant, so the rotation of the motor will change. number too
The same number of rotations can be obtained regardless of 200 [V] or 100 [V].

Furthermore, by using a third capacitor,
Regardless of whether the single-phase AC is 200 [V] or 100 [V], at least the smoothing ability of the third capacitor is ensured. That is, by reducing the ripple to a predetermined value or less, it is possible to suppress fluctuations and vibrations in the rotational speed of the electric motor.

(F) Example The following is a first example of driving a three-phase induction motor using the inverter circuit 2 of the power supply device of the present invention.
To explain based on FIG. 2, 3 to 6 are diodes constituting a diode bridge,
The anode of the first diode 3 and the second diode 4
, the anode of the third diode 5 and the cathode of the fourth diode 6 are connected, the cathode of the first diode 3 and the cathode of the third diode 5 are connected, and the anode of the second diode 4 is connected. and the anode of the fourth diode 6, and the connection point of the first and second diodes and the connection point of the third and fourth diodes are used as single-phase AC input terminals A and B, and the The connection point between the first and third diodes and the connection point between the second and fourth diodes are used as DC output terminals.
Reference numerals 7 and 8 denote first and second capacitors, which are connected in series between the output terminals. 9 is the third capacitor, and 10 is a jumper wire, one end of which is connected to the connection point (input terminal) B between the third and fourth diodes 7 and 8, and the other end connected to the connection point of the first and second capacitors 7 and 8. Connected to C. In the present invention, the jumper wire 10 is used as an example of the opening/closing means, and the open state is obtained by cutting the jumper wire 10, but the open state may be obtained by removing the jumper wire 10. be.

Note that 11 is a power supply stabilization circuit, which is composed of a noise filter, a low-pass filter, and the like.

Input terminals A and B of the device configured as above
When a single-phase 100 [V] AC power supply 12 is connected to the AC power source 12 (the state shown in FIG.
8, the voltage is doubled and rectified to obtain a DC voltage of about 200 [V], and after smoothing this rectified output with a third capacitor 9, it is supplied to the inverter circuit 2.

This inverter circuit 2 converts DC power into three-phase AC power based on PWM, and then supplies it to the three-phase induction motor 1. Therefore, if the voltage of the DC power is constant, the synchronous speed of the induction motor can be changed by changing the frequency of the three-phase AC power. In other words, it is possible to change the rotation speed of the electric motor.

Next, connect the input terminals A and B of this device with a single-phase 200Ω
When connecting the AC power supply 13 of [V] (the state shown in FIG. 2), if the jumper wire 10 is cut, this AC is connected to the first to fourth diodes 3 to 6.
It is simply full-wave rectified by a diode bridge of approx.
A DC voltage of 200 [V] is obtained and supplied to the inverter circuit 2 via the stabilizing circuit 11.

At this time, the first capacitor 7, the second capacitor 8
are connected in series, and the third capacitor 9 is further connected in parallel, so that the rectified output is smoothed by this combined capacitance.

In this way, even if the single-phase 200 [V]/single-phase 100 [V] changes, the capacity of the third capacitor 9 is always secured as a smoothing capacitor, so the single-phase 200 [V]
Regardless of [V]/single phase 100 [V], the ripple of DC power can be suppressed to the value provided by the third capacitor 9.

Therefore, single-phase 200 [V]/
A smoothed output of 200 [V] DC is always supplied with ripple less than a predetermined value regardless of the single-phase 100 [V].

Therefore, when controlling the rotation speed of the induction motor using the inverter circuit 2, single-phase 200 [V]/single-phase
The same number of rotations can be obtained regardless of the voltage of 100 [V], and at the same time, it is possible to prevent increases in undulation and vibration noise due to ripples.

(g) Effects of the invention The present invention configured as described above is a power supply device that uses an inverter circuit to control the operation of a three-phase induction motor with single-phase AC, and is capable of controlling the operation of a three-phase induction motor using single-phase AC between the input terminals. A first capacitor and a second capacitor are connected in series between the output terminals of the supplied diode bridge, and a third capacitor is connected between the output terminals of the supplied diode bridge.
A jumper wire is connected between the connection point of the first capacitor and the second capacitor and one of the input terminals, and a third capacitor is connected.
An inverter circuit that converts DC power into three-phase AC power is connected to both ends of the capacitor, and the three-phase AC power output from this inverter circuit is supplied to the induction motor. Since the jumper wire is cut or removed, the input of 200 [V]/100 by using the jumper wire is
Since the [V] input setting is changed, the 200 [V] input/100 [V] input will not be changed by mistake after the equipment is installed, which will prevent overcurrent from flowing into the inverter circuit or induction motor, or from applying overvoltage. This can prevent the lever circuit and motor from burning out.

In addition, by using a third capacitor after the jumper wire, the voltage of the single-phase AC power supply can be increased to 200
[V]/100 [V], the ripple of the DC power supplied to the inverter circuit can be suppressed to a predetermined value or less. In other words, it is possible to provide a power supply device that suppresses vibrations, noise, and fluctuations in rotation speed of an induction motor caused by ripples, and maintains stable operation of the induction motor regardless of whether the voltage is 200 [V] or 100 [V]. It is.

[Brief explanation of the drawing]

Figure 1 is an electrical circuit diagram when a single-phase 100 [V] AC power supply is used in the embodiment of the present invention, and Figure 2 is an electrical circuit diagram when a single-phase 200 [V] AC power supply is used in the embodiment of Figure 1. It is an electric circuit diagram when 1...Induction motor, 2...Inverter circuit, 3
6 to 6...first to fourth diodes, 7 to 9...
...First to third capacitors, 10... Jumper wire, 11... Stabilization circuit, 12... Single phase 100 [V]
AC power supply, 13... Single phase 200 [V] AC power supply.

Claims (1)

[Scope of utility model registration request] In a power supply device configured to control the operation of a three-phase induction motor with single-phase AC using an inverter circuit, the anode of the first diode and the cathode of the second diode are connected, and the anode of the third diode is connected to the cathode of the third diode. The anode and the cathode of the fourth diode are connected, the cathode of the first diode and the cathode of the third diode are connected, and the anode of the second diode and the anode of the fourth diode are connected. A single-phase diode bridge is configured, and the connection point between the first diode and the second diode and the connection point between the third diode and the fourth diode are used as input terminals for single-phase AC,
The connection point between the first diode and the third diode and the connection point between the second diode and the fourth diode are used as output terminals for rectified output, and a single-phase alternating current is connected between the input terminals of this diode bridge. A first capacitor and a second capacitor are connected in series between the output terminals of the diode bridge, and a third capacitor is connected between the output terminals of the diode bridge. A shimmer wire is connected between the input terminal of either one of the terminals, and an inverter circuit that converts DC power into three-phase AC power is connected to both ends of the third capacitor, and the three-phase AC output from this inverter circuit is connected to the third capacitor. A power supply device that supplies power to the induction motor and cuts or removes the jumper wire when the single-phase AC voltage is doubled.