JPH11178351A - Control circuit with rush current preventing function, overvoltage preventing function, and discharge function and power conversion device with the control circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use a resistor which is identical to the resistor for prevention of rush current, a resistor for preventing overvoltage, and a resistor for discharging. SOLUTION: When a capacitor C1 has not been changed, a current passes through a series body of a resistor R1 and a diode D8 provided between a converter part 11, and the capacitor C1 and charges the capacitor C1. On the other hand, when the capacitor C1 has been charged, a current passes through a first switch SW1 and charges the capacitor C1 by turning on the first switch SW1 provided in parallel with the series body of the resistor R1 and the second diode D8. Furthermore, in discharging, a current passes through a second switch SW2 provided between the connection point between the resistor R1 and the second diode D8 and an electrode at the other terminal of the capacitor C1 for discharging.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control circuit having a function of preventing inrush current to a smoothing capacitor and a function of preventing and discharging an overvoltage of a smoothing capacitor in a power converter, and a power converter having the circuit. About.

[0002]

2. Description of the Related Art FIG. 15 is a diagram showing a circuit configuration of a conventional inverter device. In the figure, MC1 is an electromagnetic contactor,
10h is an inverter device, 11 is a converter unit configured by rectifiers D1 to D6 to convert AC power to DC power, C1 is a capacitor for smoothing the DC power,
12 is a switching element TR1-TR6 and a rectifier D connected in anti-parallel to the switching elements TR1-TR6.
An inverter unit configured as a bridge composed of 11 to D16 and inversely converting DC power into required AC power. SW1 is a first switch inserted into a positive output bus of the converter unit 11 between the converter unit 11 and the capacitor C1. , R1 is a resistor connected in parallel with the switch SW1 and used for preventing inrush current, R2 is a resistor used for overvoltage prevention and discharging, SW2 is a switch as a second switch, R2 and a switch The series body of SW2 is connected to both ends of the capacitor C1. M is a motor as a load.

When the AC voltage is applied, the battery is charged via the resistor R1, and when the voltage of the capacitor C1 reaches a predetermined voltage,
The switch SW1 is turned on. In some cases, the inertia energy of the motor or the like returns to the inverter device side. In this case, the voltage of the capacitor C1 increases. The voltage further rises, and the capacitor C1 and the switching elements TR1 to TR1
If the withstand voltage exceeds the allowable withstand voltage of 6, the voltage is destroyed and a failure is caused. Therefore, the switch SW2 discharges through the resistor R2 to lower the voltage of the capacitor C1.

FIG. 16 is a diagram showing a circuit configuration of a conventional inverter device, which is disclosed in Japanese Patent Application Laid-Open No. 7-99784. It is intended to be able to be used in common with a power discharge resistor, and to reduce the size and cost by reducing the number of required resistors. In the figure, 31 is an AC power supply, 32 is a circuit breaker, 33 is a voltage type inverter device, 34 is an AC motor, 41 is a rectifier, 42 is an inverter, 43 is a smoothing capacitor, 44 is a charge / discharge control circuit, and 45 is A resistor, 46 is a diode, 47 is a contact of an electromagnetic contactor, and 48 is a transistor.

A charge / discharge control circuit 44 provided between the rectifier 41 and the capacitor 43 inserts a resistor 45 and a diode 46 in series to the positive output bus of the rectifier 41 as shown in FIG. A contact 47 of an electromagnetic contactor is provided in parallel, and a transistor 48 is further provided between a connection point between the resistor 45 and the diode 462 and a negative output bus of the rectifier 41. 46 →
When the regenerative power is discharged through the path of the capacitor 43, the current is supplied through the path of the capacitor 43 → the contact 47 of the electromagnetic contactor → the resistor 45 → the transistor 48 so that both the charging and discharging currents pass through the resistor 45. is there.

[0006] As an option for fully exerting the regenerative braking capability in the conventional inverter device,
Brake units and discharge resistors or brake units and resistor units were used. FIG. 17 is an external connection diagram in which a brake unit and a discharge resistor are attached to a conventional inverter device, and FIG. 18 is an external connection diagram in which a brake unit and a resistor unit are attached to a conventional inverter device. In a conventional inverter device,
Regarding the distance between the inverter device and the brake unit and the discharge resistor, or the distance between the inverter device and the brake unit and the resistor unit, there is a restriction on the length in terms of measures against surge voltage.

[0007]

Since the conventional machining current control device of the electric discharge machine is configured as shown in FIG. 15, two resistors are required, and a large space is required. There was a problem that the cost was high.

In the conventional inverter device shown in FIG. 16, the resistor for suppressing the initial charging current and the resistor for discharging the regenerative power with respect to the rectifying voltage smoothing capacitor can be used in common. There is a problem that the capacitor 43 cannot be discharged in the open state.

Further, the capacitor or the resistor is generally built in the inverter device, and there is a problem that the capacity is limited. In addition, a non-inductive resistor having no inductance must be used, and there is a problem that the price is high.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. A first object of the present invention is to provide a control device having a function of preventing an inrush current to a capacitor and a function of preventing a capacitor from overvoltage and discharging in an inverter device. In the circuit, one resistor can be used for inrush prevention, overvoltage prevention and discharge.

A second object is to use inexpensive resistors.

A third object is to increase the capacity of a capacitor.

Still another object of the present invention is to provide a compact and lightweight power converter.

[0014]

According to the present invention, there is provided a converter for converting an AC power supply into DC power, a capacitor for smoothing the DC power, and an inverter for inversely converting the DC power to required AC power. And a control circuit having an inrush current prevention function, an overvoltage prevention function, and a discharge function in the power conversion device having: a first switch provided between the converter unit and the capacitor; and a control circuit provided in parallel with the first switch. A first diode provided in the discharge direction of the capacitor; a series body of a resistor and a second diode provided in parallel with the first switch and the first diode; and a connection point between the resistor and the second diode And a second switch provided between the capacitor and the other end of the capacitor, wherein when the capacitor is not charged, current flows through the resistor and the second diode. The capacitor is charged, and when the capacitor is in a charged state, the first switch is turned on so that the current flows through the first switch to charge the capacitor. When the capacitor is discharged, the second switch is turned on and the first switch is turned on. The current passes through the diode, the resistor, and the second switch.

When the capacitor is not charged, current flows through the resistor and the second diode to charge the capacitor.
When the capacitor is in the charged state, the first switch is turned on to pass the current through the first switch to charge the capacitor, and when the voltage of the capacitor exceeds a predetermined voltage, the second switch is turned on. Then, a current flows through the first diode, the resistor, and the second switch to discharge the charge of the capacitor.

Furthermore, a MOSFET, a transistor, an IGBT, a thyristor, and an electromagnetic relay are used as the first switch or the second switch.

Further, a control circuit having an inrush current preventing function, an overvoltage preventing function, and a discharging function according to the present invention comprises a first circuit provided between the converter unit and the capacitor.
A first diode provided in parallel with the first switch in the discharge direction of the capacitor, and first and second terminals provided at both ends of the parallel connection of the first switch and the first diode. A third terminal provided on the other end of the capacitor not connected in parallel with the first switch and the first diode, a series body of the second diode and the second switch, and a second diode. Second
And a fourth capacitor connected to the second and third terminals, and an auxiliary capacitor connected in parallel to the series body of the second diode and the second switch. A sixth terminal provided at a connection point between the second diode and the second switch, a seventh terminal connected to the first terminal, and connected to the sixth terminal and the seventh terminal. A resistor between the first terminal and the seventh terminal;
And the fourth terminal and between the third terminal and the fifth terminal are connected by a cable. When the capacitor is not charged, a current flows through the resistor and the second diode, and the capacitor and the auxiliary By charging the capacitor and turning on the first switch when the capacitor is in a charged state, a current flows through the first switch to charge the capacitor and the auxiliary capacitor, and when the capacitor and the auxiliary capacitor are discharged, , The second switch is turned on, and the current passes through the first diode, the resistor and the second switch to discharge.

Further, a control circuit having an inrush current preventing function, an overvoltage preventing function, and a discharging function according to the present invention includes a first switch provided between a converter section and a capacitor, and a first switch provided in parallel with the first switch. A first diode provided in the discharge direction of the capacitor, a resistor connected to the converter side of the parallel connection of the first switch and the first diode, and a first switch and a first switch of this resistor.
A first terminal provided on the other end side of the connection with the parallel connection of the diodes, a second terminal provided on the capacitor side of the parallel connection of the first switch and the first diode,
A third terminal provided on the other end of the capacitor not connected in parallel with the first switch and the first diode; a series body of the second diode and the second switch;
Fourth and fifth terminals provided in a series body of the second diode and the second switch and connected to the second and third terminals, and a series body of the second diode and the second switch. An auxiliary capacitor connected in parallel, and an eighth terminal provided at a connection point between the second diode and the second switch, wherein a second terminal is provided between the first terminal and the eighth terminal; A cable is connected between the terminal and the fourth terminal and between the third terminal and the fifth terminal. When the capacitor is not charged, a current flows through the resistor and the second diode, and the capacitor and the auxiliary capacitor are connected. When the capacitor is charged and the first switch is turned on when the capacitor is in a charged state, current flows through the first switch to charge the capacitor and the auxiliary capacitor. First diode turns on the switch, a resistor and a second switch current is obtained so as to as discharge.

Further, a control circuit having an inrush current preventing function, an overvoltage preventing function, and a discharging function according to the present invention includes a first switch provided between the converter section and the capacitor, and a parallel switch connected to the first switch. A first diode provided in the discharge direction of the capacitor; a resistor provided in parallel with the first switch and the first diode;
A first terminal provided at a connection point between the resistor and the second diode; and a second terminal provided on the capacitor side of a parallel connection of a first switch and a first diode. A first terminal of the capacitor, a third terminal provided on the other end side of the first switch and the first diode of the capacitor that are not connected in parallel, a series body of an auxiliary diode and a second switch, Fourth and fifth terminals provided in a series body of a diode and a second switch, connected to the second and third terminals, and connected in parallel to a series body of an auxiliary diode and the second switch. An auxiliary capacitor; and an eighth terminal provided at a connection point between the auxiliary diode and the second switch, between the first terminal and the eighth terminal, and between the second terminal and the fourth terminal. Between the terminal and the third end A cable is connected between the capacitor and the fifth terminal. When the capacitor is not charged, a current flows through the resistor and the second diode to charge the capacitor and the auxiliary capacitor. When the capacitor is charged, the first capacitor is charged. When the switch is turned on, current flows through the first switch to charge the capacitor and the auxiliary capacitor, and when the capacitor and the auxiliary capacitor are discharged, the second
Switch on the first diode, the resistor and the second
The current is passed through the switch of FIG.

Furthermore, a control circuit having an inrush current preventing function, an overvoltage preventing function, and a discharging function according to the present invention includes a resistor and a second diode provided in parallel with the first switch and the first diode. A third switch is provided in series on the capacitor side of the series body with the above.

The function of a first switch provided between the converter unit and the capacitor and a first diode provided in parallel with the first switch in the discharge direction of the capacitor may be performed using a MOSFET. It was made.

Further, a control circuit having an inrush current preventing function, an overvoltage preventing function, and a discharging function according to the present invention includes a first switch provided between the converter unit and the capacitor, and a first switch provided in parallel with the first switch. Connected resistors,
A second terminal provided on the capacitor side of the parallel connection of the first switch and the resistor, a third terminal provided on the other end of the capacitor not connected in parallel with the first switch and the resistor, Fourth and fifth terminals provided in a series body of a diode and a second switch, provided in a series body of a second diode and a second switch, and connected to the second and third terminals; An auxiliary capacitor connected in parallel with a series body of a diode and a second switch;
A sixth terminal provided at a connection point between the diode and the second switch, an auxiliary resistor connected to the sixth terminal and the fourth terminal, and the second terminal and the fourth terminal. A cable is connected between the second terminal and the third terminal and the fifth terminal. When the capacitor is not charged, a current flows through the resistor to charge the capacitor and the auxiliary capacitor. Turns on the first switch to pass a current through the first switch to charge the capacitor and the auxiliary capacitor. Further, when the capacitor and the auxiliary capacitor are discharged, the second switch is turned on and the first diode is turned on. A control circuit having an inrush current prevention function, an overvoltage prevention function, and a discharge function, characterized in that a current flows through an auxiliary resistor and a second switch to discharge.

Further, the power converter of the present invention has an inrush current prevention function and an overvoltage which are used as a resistor for preventing current to the power converter, a resistor for preventing overvoltage of DC voltage and a resistor for discharging. A control circuit having a prevention function and a discharge function is provided.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a diagram showing a circuit configuration of an inverter device according to an embodiment of the present invention. In the figure, MC1 is an electromagnetic contactor, 10a is an inverter as a power converter, 11 is a rectifier D1
To D6, a converter section for converting an AC power supply into DC power, C1 a capacitor for smoothing the DC power, 12 a switching element TR1 to TR6 and a rectifier D11 connected anti-parallel to the switching element TR1 to TR6. An inverter section configured as a bridge by D16 and inversely converting DC power to required AC power, SW1
Is a switch as a first switch inserted into the positive output bus of the converter section 11 between the converter section 11 and the capacitor C1, and D7 is connected in parallel with the switch SW1 such that the cathode is on the converter section 11 side. First
R1 is a resistor used for rush current prevention, overvoltage prevention and discharge,
D8 is a diode as a second diode connected in series with the resistor R1 such that the cathode is on the positive terminal side of the capacitor C1, and a series connection of the resistor R1 and the diode D8 is connected in parallel with the switch SW1 and the diode D7. Is done. SW2 is a switch inserted between the connection point between the resistor R1 and the diode D8 and the negative output bus of the converter unit 11, and M is a motor as a load. 13a
Is a control circuit composed of a switch SW1, a diode D7, a resistor R1, a diode D8 and a switch SW2 for preventing inrush current, preventing overvoltage and discharging.

FIG. 2 is a diagram showing a time chart and waveforms for explaining the operation of the inverter device according to one embodiment of the present invention. In the figure, (a) is an electromagnetic contactor M
C1 is a time chart, (b) is a state of charging and discharging of the capacitor C1, and (c) is a time chart of the switch SW1. When the electromagnetic contactor MC1 is turned on, the capacitor C1 is in an uncharged state, so that the resistor R1
And the capacitor C1 is charged through the diode D8. Assuming that the capacitor C1 is in a charged state from the time when the voltage V1 of the capacitor C1 is reached, the switch SW1 is turned on after a time T1, and the capacitor C1 is charged through the switch SW1. Time T1 may be zero, but V1
Prolonging the time has the effect of further reducing the inrush current. When the switch SW1 is turned on, the DC output of the rectifier circuit is completely charged in the capacitor C1, so that the switching elements TR1 to TR6 can be operated to supply power to a load such as a motor. Electromagnetic contactor MC when power is turned off
When 1 is turned off, the voltage of the capacitor C1 decreases,
When a predetermined voltage V2 lower than V1 is reached, the switch SW1
Off.

FIG. 3 shows a time chart and waveforms for explaining the operation of the inverter device according to one embodiment of the present invention at the time of overvoltage. In the figure, (a) shows a state of charging and discharging of the capacitor C1, and (b) shows a time chart of the switch SW2. When the voltage of the capacitor C1 rises and reaches a predetermined voltage V3, the switch SW2 is turned on, and the charge of the capacitor C1 is discharged through the diode D7, the resistor R1 and the switch SW2, and when the voltage reaches the predetermined voltage V4, the switch SW2 is turned off. Charge the capacitor C1. As described above, the on / off control of the switch SW2 controls the voltage of the capacitor C1 so as not to exceed the predetermined voltage V3.

FIG. 4 is a diagram showing a time chart and waveforms for explaining the operation at the time of rapid discharge of the inverter device according to one embodiment of the present invention. In the figure, (a) is a time chart of the electromagnetic contactor MC1, (b) is a state of charging and discharging of the capacitor C1, and (c) is a switch SW.
1 is a time chart, and (d) shows a time chart of the switch SW2. After the electromagnetic contactor MC1 is turned off, the electric charge of the capacitor C1 is discharged, and the switch SW2 is turned on so that the current flows through the resistor R1 and is rapidly discharged. In this case, the switch SW1 is turned off after the switch SW2 is turned on. After confirming the discharge, the switch SW2 is turned off.

Conventionally, a high resistance is connected to the capacitor C1 to discharge over a long period of time. In this embodiment, however, this resistance can be omitted. Since the resistor connected to the capacitor C1 always consumes power while the power is turned on, omitting this resistor saves energy.

FIG. 5 is a diagram showing a time chart and waveforms for explaining the operation of the inverter device according to one embodiment of the present invention at the time of overvoltage. In the figure, (a) shows a state of charging and discharging of the capacitor C1, and (b) shows a time chart of pulse width control of the switch SW2. When the voltage of the capacitor C1 exceeds the predetermined voltage V5, the switch SW2 is turned on, and when the voltage of the capacitor C1 becomes equal to or lower than the predetermined voltage V5, the switch SW2 is turned off so that the voltage of the capacitor C1 does not greatly exceed V5. Things.

FIG. 6 is a diagram showing a circuit configuration of a control circuit for preventing rush current, preventing overvoltage and discharging in the inverter device according to one embodiment of the present invention. In the control circuit 13a for preventing inrush current, for preventing overvoltage and for discharging in FIG. 1, MOS switches are used as the switches SW1 and SW2.
FET (metal oxide semiconductor field effect transistor, metal
This is an example using an oxide semiconductor field-effect transistor). In this case, the MO of the switch SW1 is
Since the SFET has a built-in diode in the reverse direction, the diode D7 becomes unnecessary.

FIG. 7 is a diagram showing a circuit configuration of a control circuit for preventing rush current, preventing overvoltage and discharging in the inverter device according to one embodiment of the present invention. In the control circuit 13a for preventing inrush current, preventing overvoltage and discharging in FIG. 1, IGBs are used as the switches SW1 and SW2.
This is an example using T.

FIG. 8 is a diagram showing a circuit configuration of a control circuit for preventing rush current, preventing overvoltage and discharging in the inverter device according to one embodiment of the present invention. FIG. 7 shows an example in which a thyristor is used as the switch SW1.

Although not shown, the switches SW1,
Similar effects can be obtained by using a transistor or an electromagnetic relay as SW2.

Embodiment 2 FIG. 9 is a diagram showing a circuit configuration of the inverter device according to one embodiment of the present invention.
In the figure, MC1, 11, D1 to D6, 12, TR1
TR6, D11 to D16, C1, and M are the same as those in FIG. 1 described above, and a description thereof will be omitted. 10b is an inverter device as a power conversion device. The switch SW1 as the first switch is composed of the converter unit 11 and the capacitor C
1, a diode D7 as a first diode is connected in parallel with the switch SW1 such that the cathode is on the converter unit 11 side, and the diode D8 is connected to the cathode side of the diode D8. The series connection connected to become the resistor R1 is a switch S
It is connected in parallel with W1 and diode D7. Also,
The switch SW2 is connected to a connection point between the resistor R1 and the diode D8 and the positive output bus side of the converter unit 11.
Reference numeral 13b denotes a control circuit for preventing an inrush current, an overvoltage, and a discharge, including a switch SW1, a diode D7, a resistor R1, a diode D8, and a switch SW2. FIG. 9 shows a circuit in which the positive voltage side and the negative voltage side of the circuit of FIG. 1 are connected in reverse, and performs the same operation as the circuit of FIG.

Embodiment 3 FIG. FIG. 10 is a diagram showing a circuit configuration of the inverter device according to one embodiment of the present invention. In the figure, MC1, 11, D1 to D6, 12, T
R1 to TR6, D11 to D16, C1, SW1, D7,
M is the same as in FIG. 1 described above, and a description thereof will be omitted.
10c is an inverter device as a power converter, P11
Is a first terminal, P12 is a second terminal, N1 is a third terminal, P22 is a fourth terminal, N2 is a fifth terminal, PR is a sixth terminal, P21 is a seventh terminal, and R1 is A resistor, D8 is a diode, SW2 is a switch, and C2 is an auxiliary capacitor. In the inverter device 10c, the terminal P11
Is connected to the cathode side of the diode D7, the terminal P12 is connected to the anode side of the diode D7, and the terminal N1 is connected to the negative output bus side of the converter unit 11. In the brake unit including the diode D8, the switch SW2, and the capacitor C2, the cathode of the diode D8 is connected to the terminal P22, the switch SW2 is connected in series to the diode D8, and connected to the terminal N2, and the capacitor C2 is connected to the diode. It is connected in parallel with the series connection of D8 and switch SW2. Also, a diode D8 and a switch SW
2 is connected to a terminal PR, and a resistor R1 is connected between the terminal P21 and the terminal PR. Inverter device 10
The terminal P11, the terminal P12 and the terminal N1 on the c side are connected to the terminal P21, the terminal P22 and the terminal N on the brake unit side.
2 and cable connection.

FIG. 10 shows a control circuit 13 for preventing inrush current, overvoltage prevention and discharging, which comprises the switch SW1, the diode D7, the resistor R1, the diode D8 and the switch SW2 of FIG. 1 shown in the first embodiment. The resistance R
1, switch SW2, diode D8 (brake part)
Is taken out of the inverter device, and the operation is the same as that shown in FIG.

In this embodiment, the surge voltage to be generated when the switch SW2 is turned off is the diode D
Since the voltage is absorbed by the capacitor C2 through the capacitor 8, no surge voltage is generated, and there is no restriction on the distance of the portion (the resistor R1, the switch SW2, and the diode D8) taken out of the inverter to the inverter.

Further, in this embodiment, a normal resistor, generally a winding resistor or the like can be used, and the cost is reduced. Furthermore, if a large-capacity electrolytic capacitor is used as the capacitor C2, the capacity limited by the size of the capacitor C1 in the inverter device can be added, and the ripple voltage of the DC voltage can be reduced or the AC voltage can be reduced. It has the effect of strengthening against momentary power outages.

Embodiment 4 FIG. 11 is a diagram showing a circuit configuration of the inverter device according to one embodiment of the present invention. In the figure, MC1, 11, D1 to D6, 12, T
R1 to TR6, D11 to D16, C1, SW1, D7,
R1 and M are the same as those in FIG. 1 described above, and a description thereof will be omitted. 10d is an inverter device as a power converter,
P11 is a first terminal, P12 is a second terminal, N1 is a third terminal.
, P22 is a fourth terminal, N2 is a fifth terminal, P2
3 is an eighth terminal, D8 is a diode, SW2 is a switch, and C2 is an auxiliary capacitor. In the inverter device 10d, the terminal P11 is connected to the other end of the resistor R1 whose one end is connected to the cathode of the diode D7,
2 is connected to the anode side of the diode D7, and the terminal N1 is connected to the negative output bus side of the converter unit 11. Also, a diode D8, a switch SW2, a capacitor C2
In the brake unit composed of
8 has a cathode connected to the terminal P22 and a switch SW
2 is connected in series with the diode D8 and connected to the terminal N2 side, and the capacitor C2 is connected to the diode D8 and the switch SW2.
Is connected in parallel with the series connection. The terminal P23 is connected to a connection point between the diode D8 and the switch SW2. Terminal P11, terminal P12 on the inverter device 10d side
And the terminal N1 is a terminal P23 on the brake unit side,
Cables are respectively connected to the terminal P22 and the terminal N2.

FIG. 10 of the third embodiment shows an example in which a brake unit composed of a diode D8, a switch SW2, and a capacitor C2 and a resistor R1 are externally provided. The brake unit is mounted inside the inverter device and externally includes a brake unit including a diode D8, a switch SW2, and a capacitor C2.

Embodiment 5 FIG. FIG. 12 is a diagram showing a circuit configuration of the inverter device according to one embodiment of the present invention. In the figure, MC1, 11, D1 to D6, 12, T
R1 to TR6, D11 to D16, C1, SW1, D7,
R1, D8, SW2, and M are the same as those in FIG.
The description is omitted. 10e is an inverter device as a power converter, P11 is a first terminal, P12 is a second terminal, N1 is a third terminal, P12 is a fourth terminal, N2 is a fifth terminal, and P23 is an eighth terminal. A terminal D8a is a diode used as an auxiliary for the diode D8 as a second diode, SW2 is a switch, and C2 is an auxiliary capacitor. In the inverter device 10e, the terminal P1
1 is connected to the other end of the resistor R1 whose one end is connected to the cathode of the diode D7, the terminal P12 is connected to the anode of the diode D7, and the terminal N1 is connected to the negative output bus of the converter unit 11. In the brake unit including the diode D8a, the switch SW2, and the capacitor C2, the cathode of the diode D8a is connected to the terminal P2.
The switch SW2 is connected in series with the diode D8a and connected to the terminal N2, and the capacitor C2 is connected in parallel with the series connection of the diode D8a and the switch SW2. The terminal P23 is connected to a connection point between the diode D8a and the switch SW2. Inverter device 1
The terminals P11, P12, and N1 on the 0e side are cable-connected to the terminals P23, P22, and N2 on the brake unit side, respectively.

In this embodiment, the switch SW2 in FIG. 1 of the first embodiment is provided in an external brake unit, and the terminal P11 and the terminal P12 on the inverter device side in the fourth embodiment are used. The diode D8 is connected so that the cathode is on the positive terminal side of the capacitor C2, the diode D8 and the capacitor C1 are provided on the inverter device 10e side, and the diode D8a and the capacitor C2 are provided on the brake unit side. It was done.

Embodiment 6 FIG. FIG. 13 is a diagram showing a circuit configuration of the inverter device according to one embodiment of the present invention. In the figure, MC1, 11, D1 to D6, 12, T
R1 to TR6, D11 to D16, C1, SW1, D7,
R1, D8, SW2, and M are the same as those in FIG.
The description is omitted. 10f is an inverter device as a power conversion device. FIG. 13 shows the resistance R in FIG.
1. A third switch SW3 is provided in series between a series connection of a diode D8 and a positive terminal of a capacitor C1.

By appropriately opening the switch SW3,
The charging current of the capacitor C1 can be limited. Further, the switch SW1, the switch SW2 and the switch S
By turning off all W3, it is possible to electrically disconnect from the alternating current, and it is possible to enhance the operational safety.

Embodiment 7 FIG. 14 is a diagram showing a circuit configuration of the inverter device according to one embodiment of the present invention. In the figure, MC1, 11, D1 to D6, 12, T
R1 to TR6, D11 to D16, C1, SW1, R1,
SW2 and M are the same as those in FIG. 1 described above, and a description thereof will be omitted. 10g is an inverter device as a power converter, P12 is a second terminal, N1 is a third terminal, P22 is a fourth terminal, N2 is a fifth terminal, PR is a sixth terminal, R
2 is an auxiliary resistor, D8 is a diode, SW2 is a switch, and C2 is an auxiliary capacitor. In the inverter device 10g, the terminal P12 is connected to the capacitor C of the resistor R1.
1 is connected to the positive terminal side, and the terminal N1 is connected to the negative output bus side of the converter section 11. The diode D
8, a switch SW2 and a capacitor C2, the diode D8 has a cathode connected to the terminal P22 side, and the switch SW2 has a diode D2.
8 connected in series with the terminal N2, and a capacitor C2
Is connected in parallel with the series connection of the diode D8 and the switch SW2. A terminal PR is connected to a connection point between the diode D8 and the switch SW2, and a resistor R2 is connected between the terminal P22 and the terminal PR. The terminals P12 and N1 on the side of the inverter device 10g are connected to the terminals P22 and N2 on the side of the brake unit by cables.

In FIG. 10 of the third embodiment,
Although the example in which the brake unit including the diode D8, the switch SW2, and the capacitor C2 and the resistor R1 are externally provided has been described, in this embodiment, the resistor R1 is mounted in the inverter device, and the diode D8 and the switch SW are connected.
2. An external brake unit composed of a capacitor C2 and an external resistor R2 as a discharge resistor.

When the capacitor C1 in the inverter device is not charged, a current flows through the resistor R1, and when the capacitor C1 is charged, the switch SW1 is turned on to pass a current through the switch SW1. Is discharged by a resistor R2 externally connected to the inverter device.

In the above-described embodiment, an inverter device has been described as an example of a power conversion device. However, other electric devices, rectifying an alternating current, converting the alternating current into a direct current, accumulating charges in a capacitor, and utilizing the direct current voltage are utilized. The same effect can be obtained even if it performs AC conversion, voltage conversion, current conversion, or the like.

[0049]

Since the present invention is configured as described above, it has the following effects.

A control circuit having an inrush current preventing function, an overvoltage preventing function, and a discharging function according to the present invention includes a first switch provided between a converter unit and a capacitor;
A first diode provided in parallel with the first switch in the discharge direction of the capacitor, a series body of a resistor and a second diode provided in parallel with the first switch and the first diode; A second switch provided between a connection point with the second diode and an electrode at the other end of the capacitor. When the capacitor is not charged, current flows through the resistor and the second diode to charge the capacitor. ,
When the capacitor is in a charged state, the first switch is turned on to pass a current through the first switch to charge the capacitor. When the capacitor is discharged, the second switch is turned on and the first diode, the resistor and Since the current is passed through the second switch and discharged, the same resistor can be used as the inrush current prevention resistor, the overvoltage prevention resistor, and the discharge resistor, and the size and the cost can be reduced.

When the capacitor is not charged, current flows through the resistor and the second diode to charge the capacitor.
When the capacitor is in the charged state, the first switch is turned on to pass the current through the first switch to charge the capacitor, and when the voltage of the capacitor exceeds a predetermined voltage, the second switch is turned on. Since current flows through the first diode, the resistor, and the second switch to discharge the charge of the capacitor, overvoltage of the capacitor can be easily prevented.

Furthermore, a control circuit having an inrush current preventing function, an overvoltage preventing function, and a discharging function according to the present invention includes a first circuit provided between the converter section and the capacitor.
A first diode provided in parallel with the first switch in the discharge direction of the capacitor, and first and second terminals provided at both ends of the parallel connection of the first switch and the first diode. A third terminal provided on the other end of the capacitor not connected in parallel with the first switch and the first diode, a series body of the second diode and the second switch, and a second diode. Second
And a fourth capacitor connected to the second and third terminals, and an auxiliary capacitor connected in parallel to the series body of the second diode and the second switch. A sixth terminal provided at a connection point between the second diode and the second switch, a seventh terminal connected to the first terminal, and connected to the sixth terminal and the seventh terminal. A resistor between the first terminal and the seventh terminal;
And the fourth terminal and between the third terminal and the fifth terminal are connected by a cable, and when the capacitor is not charged, current flows through the resistor and the second diode, and the capacitor and the auxiliary capacitor And when the capacitor is in the charged state, the first switch is turned on to charge the first switch.
When the capacitor and the auxiliary capacitor are discharged, the second switch is turned on and the current is discharged through the first diode, the resistor and the second switch when the capacitor and the auxiliary capacitor are discharged. As a result, the surge voltage that is generated when the second switch is turned off is absorbed by the auxiliary capacitor through the second diode. There is no limit to the distance between the inverter SW2 and the diode D8). Further, if a large-capacity electrolytic capacitor is used as the auxiliary capacitor, the capacitor C1 in the inverter device can add a capacity limited by its size, and can reduce the ripple voltage of the DC voltage and the AC voltage. It has the effect of strengthening against instantaneous power outages. In addition, normal resistance,
Generally, winding resistance and the like can be used, and the cost is low.

Further, a control circuit having an inrush current preventing function, an overvoltage preventing function and a discharging function according to the present invention includes a first switch provided between a converter unit and the capacitor, and a first switch provided between the converter and the capacitor. A first diode provided in parallel in the discharge direction of the capacitor, a resistor connected to the converter portion side of the parallel connection of the first switch and the first diode, and a first switch and a first diode of this resistor A first terminal provided on the other end side of the connection with the parallel connection of the first, a second terminal provided on the capacitor side of the parallel connection of the first switch and the first diode, a first switch of the capacitor, A third terminal provided on the other end of the first diode that is not connected in parallel, a series body of the second diode and the second switch, and a second diode. And a fourth switch connected to the second and third terminals and connected in parallel to a series body of the second diode and the second switch. An auxiliary capacitor; and an eighth terminal provided at a connection point between the second diode and the second switch, wherein an eighth terminal is provided between the first terminal and the eighth terminal.
And the fourth terminal and between the third terminal and the fifth terminal are connected by a cable, and when the capacitor is not charged, current flows through the resistor and the second diode, and the capacitor and the auxiliary capacitor And when the capacitor is in the charged state, the first switch is turned on to charge the first switch.
When the capacitor and the auxiliary capacitor are discharged, the second switch is turned on and the current is discharged through the first diode, the resistor and the second switch when the capacitor and the auxiliary capacitor are discharged. As a result, the surge voltage to be generated when the second switch is turned off is absorbed by the auxiliary capacitor through the second diode, and is extracted outside the inverter device (switch SW2, diode D8). There is no limit on the distance to the inverter device. Also, if a large-capacity electrolytic capacitor is used for the auxiliary capacitor,
The capacity limited by the size of the capacitor C1 in the inverter device can be added, which has the effect of reducing the ripple voltage of the DC voltage and increasing the resistance to the instantaneous blackout of AC.

Further, a control circuit having an inrush current preventing function, an overvoltage preventing function, and a discharging function according to the present invention includes a first switch provided between a converter section and a capacitor, and a first switch provided in parallel with the first switch. A first diode provided in the discharge direction of the capacitor; a resistor provided in parallel with the first switch and the first diode;
, A first terminal provided at a connection point between the resistor and the second diode, and a second terminal provided on the capacitor side of the parallel connection of the first switch and the first diode. A third terminal provided on the other end of the capacitor, which is not connected in parallel with the first switch and the first diode, and an auxiliary diode and a second terminal.
A fourth body and a fourth body connected to the second and third terminals, and a fourth body and a fifth terminal provided in the series body of the auxiliary diode and the second switch. An auxiliary capacitor connected in parallel to a series body of the first switch and an eighth terminal provided at a connection point between the auxiliary diode and the second switch, wherein a first terminal and an eighth terminal are provided. And between the second terminal and the fourth terminal and between the third terminal and the fifth terminal. When the capacitor is not charged, a current flows through the resistor and the second diode. When the capacitor is in a charged state, the first switch is turned on so that current flows through the first switch to charge the capacitor and the auxiliary capacitor, and the capacitor and the auxiliary capacitor are charged. When discharging the capacitor, the second switch is turned on to discharge current through the first diode, the resistor and the second switch. Therefore, if a large-capacity electrolytic capacitor is used as the auxiliary capacitor, the inverter device can be used. The capacitor inside can add the capacity limited by its size, which has the effect of reducing the ripple voltage of the DC voltage and strengthening against the instantaneous blackout of AC.

Further, the third switch is provided in series on the capacitor side of the series body of the resistor and the second diode provided in parallel with the first switch and the first diode. By opening the switch of No. 3, the charging current of the capacitor can be limited.
Further, by turning off all of the first switch, the second switch, and the third switch, it is possible to electrically disconnect from the alternating current, and to enhance the operational safety.

The function of the first switch provided between the converter unit and the capacitor and the function of the first diode provided in parallel with the first switch in the discharging direction of the capacitor may be performed by using a MOSFET. Therefore, it is not necessary to use the first diode, and the number of components can be reduced.

Further, a control circuit having an inrush current preventing function, an overvoltage preventing function, and a discharging function according to the present invention includes a first switch provided between the converter section and the capacitor, and a control circuit provided in parallel with the first switch. Connected resistors,
A second terminal provided on the capacitor side of the parallel connection of the first switch and the resistor, a third terminal provided on the other end of the capacitor not connected in parallel with the first switch and the resistor, Fourth and fifth terminals provided in a series body of a diode and a second switch, provided in a series body of a second diode and a second switch, and connected to the second and third terminals; An auxiliary capacitor connected in parallel with a series body of a diode and a second switch;
A sixth terminal provided at a connection point between the diode and the second switch, an auxiliary resistor connected to the sixth terminal and the fourth terminal, and the second terminal and the fourth terminal. A cable is connected between the second terminal and the third terminal and the fifth terminal. When the capacitor is not charged, a current flows through the resistor to charge the capacitor and the auxiliary capacitor. Turns on the first switch to pass a current through the first switch to charge the capacitor and the auxiliary capacitor. Further, when the capacitor and the auxiliary capacitor are discharged, the second switch is turned on to turn on the first diode, Since the current flows through the auxiliary resistor and the second switch, the auxiliary resistor externally connected to the inverter device regardless of the on / off state of the first switch. It can discharge of the capacitor by.

In the power converter of the present invention, the inrush current preventing resistor, the overvoltage preventing resistor, and the discharging resistor can be shared by the same resistor, and the inrush current preventing function, the overvoltage preventing function, and the discharging function are provided. Since it has a control circuit with
Small size and low price. Further, by using a part of the control circuit having the inrush current prevention function, the overvoltage prevention function, and the discharge function as an external circuit, it is possible to use a normal resistor, generally a winding resistor, etc. It can be low price. In addition, the auxiliary capacitor for the external circuit facilitates the addition of the capacitor capacity, and has the effect of reducing the ripple voltage of the DC voltage and strengthening against the instantaneous blackout of AC.

[Brief description of the drawings]

FIG. 1 is a diagram showing a circuit configuration of an inverter device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a time chart and waveforms for explaining the operation of the inverter device according to one embodiment of the present invention;

FIG. 3 is a diagram showing a time chart and waveforms for explaining an operation of the inverter device according to the embodiment of the present invention at the time of overvoltage.

FIG. 4 is a diagram showing a time chart and waveforms for describing an operation at the time of rapid discharge of the inverter device according to one embodiment of the present invention;

FIG. 5 is a diagram showing a time chart and waveforms for explaining the operation of the inverter device according to the embodiment of the present invention at the time of overvoltage.

FIG. 6 is a diagram showing a circuit configuration of a control circuit for preventing inrush current, for preventing overvoltage, and for discharging in the inverter device according to one embodiment of the present invention (an example using MOSFETs);

FIG. 7 is a diagram showing a circuit configuration of a control circuit for preventing rush current, preventing overvoltage and discharging in the inverter device according to one embodiment of the present invention (an example using an IGBT).

FIG. 8 is a diagram showing a circuit configuration of a control circuit for preventing inrush current, preventing overvoltage, and discharging in the inverter device according to one embodiment of the present invention (an example using a thyristor);

FIG. 9 is a diagram showing a circuit configuration of an inverter device according to one embodiment of the present invention.

FIG. 10 is a diagram showing a circuit configuration of an inverter device according to one embodiment of the present invention.

FIG. 11 is a diagram showing a circuit configuration of an inverter device according to one embodiment of the present invention.

FIG. 12 is a diagram showing a circuit configuration of an inverter device according to one embodiment of the present invention.

FIG. 13 is a diagram showing a circuit configuration of an inverter device according to one embodiment of the present invention.

FIG. 14 is a diagram showing a circuit configuration of an inverter device according to one embodiment of the present invention.

FIG. 15 is a diagram showing a circuit configuration of a conventional inverter device.

FIG. 16 is a diagram showing a circuit configuration of a conventional inverter device (described in Japanese Patent Application Laid-Open No. 7-99784).

FIG. 17 is an external connection diagram in which a brake unit and a discharge resistor are attached to a conventional inverter device.

FIG. 18 is an external connection diagram in which a brake unit and a resistor unit are attached to a conventional inverter device.

[Explanation of symbols]

10a, 10b, 10c, 10d, 10e, 10f, 1
0g inverter device, 11 converter section, 12
Inverter section, 13a, 13b For rush current prevention,
Control circuit for overvoltage prevention and discharge, C1, C2
Capacitor, D7 diode, D8, D8a diode, D1-D6 rectifier, D11-D16 rectifier, M motor, MC1 electromagnetic contactor, R1,
R2 resistor, SW1, SW2 switch, TR1-T
R6 switching element, P11 first terminal, P1
2 2nd terminal, P21 7th terminal, P22 4th
Terminal, P23 eighth terminal, N1 third terminal,
N2 5th terminal, PR 6th terminal.

Claims (10)

[Claims] A converter for converting AC power into DC power; a capacitor for smoothing the DC power; an inverter for inversely converting the DC power to required AC power;
A control circuit provided with an inrush current prevention function, an overvoltage prevention function, and a discharge function in a power conversion device having: a first switch provided between the converter section and the capacitor; A first diode provided in parallel with the discharge direction of the capacitor; a series body of a resistor and a second diode provided in parallel with the first switch and the first diode; A second switch provided between the connection point of the diode and the electrode at the other end of the capacitor;
When the capacitor is in an uncharged state, a current flows through the resistor and the second diode to charge the capacitor, and when the capacitor is in a charged state, the first switch is turned on so that the first switch is turned on. Current flows through the switch to charge the capacitor. Further, when the capacitor is discharged, the second switch is turned on and the first switch is turned on.
A control circuit having an inrush current prevention function, an overvoltage prevention function, and a discharge function, characterized in that a current flows through the diode, the resistor, and the second switch. 2. When the capacitor is not charged, a current flows through the resistor and the second diode to charge the capacitor, and when the capacitor is charged, the first switch is turned on. When a current flows through the first switch and charges the capacitor, and when the voltage of the capacitor becomes a predetermined voltage or more, the second
2. The switch according to claim 1, wherein a current passes through the first diode, the resistor and the second switch to discharge the capacitor.
A control circuit having the inrush current prevention function, the overvoltage prevention function, and the discharge function described above. 3. The method according to claim 1, wherein the first switch or the second switch is a MOSFET, a transistor, an IGBT,
3. The control circuit according to claim 1, wherein the control circuit comprises an inrush current preventing function, an overvoltage preventing function, and a discharging function. A converter for converting the AC power into DC power, a capacitor for smoothing the DC power, and an inverter for inversely converting the DC power into required AC power;
A control circuit provided with an inrush current prevention function, an overvoltage prevention function, and a discharge function in a power converter having: a first switch provided between the converter section and the capacitor; and a first switch provided between the converter section and the capacitor. A first diode provided in parallel with the discharge direction of the capacitor; first and second terminals provided at both ends of a parallel connection of the first switch and the first diode;
A third terminal provided at the other end of the capacitor not connected in parallel to the first switch and the first diode; a series body of a second diode and a second switch; And a fourth and a fifth terminal connected to the second and third terminals, and a series connection of the second diode and the second switch. An auxiliary capacitor connected in parallel to the body, a sixth terminal provided at a connection point between the second diode and the second switch,
A seventh terminal connected to the first terminal; and a resistor connected to the sixth terminal and the seventh terminal, wherein the second terminal is connected between the first terminal and the seventh terminal. Terminal and the fourth
And the third terminal and the fifth terminal are connected by a cable, and when the capacitor is not charged, a current flows through the resistor and the second diode and the capacitor and the auxiliary And charging the capacitor and the auxiliary capacitor by passing a current through the first switch by turning on the first switch when the capacitor is in a charged state,
Further, when the capacitor and the auxiliary capacitor are discharged, the second switch is turned on to discharge current through the first diode, the resistor, and the second switch. A control circuit having a current prevention function, an overvoltage prevention function, and a discharge function. 5. A converter for converting AC power into DC power, a capacitor for smoothing the DC power, and an inverter for inversely converting the DC power to required AC power.
A control circuit provided with an inrush current prevention function, an overvoltage prevention function, and a discharge function in a power converter having: a first switch provided between the converter section and the capacitor; and a first switch provided between the converter section and the capacitor. A first diode provided in parallel with the discharge direction of the capacitor, a resistor connected to the converter unit side of the parallel connection of the first switch and the first diode, and a first diode of the resistor. A first terminal provided on the other end of the connection between the switch and the first diode connected in parallel, and a second terminal provided on the capacitor side of the parallel connection of the first switch and the first diode. A third terminal provided on the other end of the capacitor not connected in parallel to the first switch and the first diode; And a fourth and fifth terminal provided in a series body of the diode and the second switch, and a series body of the second diode and the second switch, and connected to the second and third terminals. An auxiliary capacitor connected in parallel with a series body of the second diode and the second switch; and an auxiliary capacitor connected to the second diode and the second switch.
An eighth terminal provided at a connection point with the second switch, wherein the second terminal is provided between the first terminal and the eighth terminal;
And the fourth terminal and between the third terminal and the fifth terminal are connected by a cable, and when the capacitor is not charged, a current flows through the resistor and the second diode. Charge the capacitor and the auxiliary capacitor, and when the capacitor is in a charged state, turn on the first switch to allow current to flow through the first switch and charge the capacitor and the auxiliary capacitor. Further, when the capacitor and the auxiliary capacitor are discharged, the second switch is turned on so that a current flows through the first diode, the resistor, and the second switch. A control circuit having an inrush current prevention function, an overvoltage prevention function, and a discharge function. 6. A converter for converting an AC power supply to DC power, a capacitor for smoothing the DC power, and an inverter for inversely converting the DC power to required AC power.
A control circuit provided with an inrush current prevention function, an overvoltage prevention function, and a discharge function in a power conversion device having: a first switch provided between the converter section and the capacitor; A first diode provided in parallel with the discharge direction of the capacitor; a series body of a resistor and a second diode provided in parallel with the first switch and the first diode; A first terminal provided at a connection point with the first diode, a second terminal provided on the capacitor side of the parallel connection of the first switch and the first diode, and the first switch of the capacitor And a third terminal provided on the other end of the first diode that is not connected in parallel, and a series connection of an auxiliary diode and a second switch. And fourth and fifth terminals provided in a series body of the auxiliary diode and the second switch and connected to the second and third terminals; and the auxiliary diode and the second switch. An auxiliary capacitor connected in parallel with a series body of a switch, and an eighth terminal provided at a connection point between the auxiliary diode and the second switch, wherein the first terminal and the second terminal are connected to each other. 8 and between the second terminal and the fourth terminal, and between the third terminal and the fifth terminal, and when the capacitor is not charged, When a current flows through a resistor and the second diode, the capacitor and the auxiliary capacitor are charged. When the capacitor is in a charged state, the first switch is turned on so that a current flows through the first switch. Said The capacitor and the auxiliary capacitor are charged, and when the capacitor and the auxiliary capacitor are discharged, the second switch is turned on to discharge current through the first diode, the resistor, and the second switch. A control circuit having an inrush current preventing function, an overvoltage preventing function, and a discharging function. 7. A third switch is provided in series on the capacitor side of a series body of the resistor and the second diode, which is provided in parallel with the first switch and the first diode. A control circuit having an inrush current prevention function, an overvoltage prevention function, and a discharge function according to claim 1 or 2. 8. A first switch provided between the converter unit and the capacitor, and a first switch provided in parallel with the first switch in a discharging direction of the capacitor.
8. A control circuit having an inrush current prevention function, an overvoltage prevention function, and a discharge function according to claim 1, wherein the function of the diode is executed by using a MOSFET. . 9. A converter for converting an AC power supply to DC power, a capacitor for smoothing the DC power, and an inverter for inversely converting the DC power to required AC power.
A control circuit provided with an inrush current prevention function, an overvoltage prevention function, and a discharge function in a power conversion device having: a first switch provided between the converter section and the capacitor; A second terminal provided on the capacitor side of the parallel connection of the first switch and the resistor;
A third terminal provided on the other end of the capacitor where the first switch and the resistor are not connected in parallel; a series body of a second diode and a second switch;
A fourth terminal provided in a series body of the second diode and the second switch and connected to the second and third terminals.
And a fifth terminal, the second diode and the second
An auxiliary capacitor connected in parallel with a series body of the second switch, a sixth terminal provided at a connection point between the second diode and the second switch, the sixth terminal and the fourth terminal. An auxiliary resistor connected to a terminal, and a cable connection between the second terminal and the fourth terminal and between the third terminal and the fifth terminal, When the capacitor is not charged, current flows through the resistor to charge the capacitor and the auxiliary capacitor, and when the capacitor is charged, turning on the first switch causes current to flow through the first switch. Charging the capacitor and the auxiliary capacitor as
Further, when the capacitor and the auxiliary capacitor are discharged, the second switch is turned on to discharge current through the first diode, the auxiliary resistor, and the second switch. A control circuit having an inrush current prevention function, an overvoltage prevention function, and a discharge function. 10. A power conversion device comprising a control circuit having an inrush current prevention function, an overvoltage prevention function, and a discharge function according to any one of claims 1 to 9.