JPH118977A - Fusing circuit of inverter fuse device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of secondary accidents of an inverter device with a single fuse, even if the main circuit element group of the inverter device or the semiconductor switching element of a DC/DC converter part is short- circuited. SOLUTION: This circuit consists of an inverter 3, and a DC/DC converter provided with a pulse transformer whose one end of a primary winding is connected to the positive electrode of a serial connection body of a DC power source 1 and a fuse 2, a semiconductor switching element 5 whose output terminal is connected to the other end of the primary side winding 4 of the pulse transformer, and a resistor element 6 which is connected between a negative electrode of the serial connection body of the DC power source 1 and the fuse 2, and the other remaining output terminal of the semiconductor switching element 5. In this case, serial connection bodies 7a, 7b of more than one diodes are also provided, whose anode side is connected with the connection point of the resistor element 6 and the semiconductor switching element 5, and whose cathode side is connected with the negative electrode of the serial connection body of the DC power source 1 and the fuse 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter device using a semiconductor switching device, and more particularly to a fuse blowing circuit of the inverter device for preventing occurrence of a secondary disaster when the semiconductor switching device is damaged.

[0002]

2. Description of the Related Art FIG. 4 shows a first configuration example of a conventional fuse blowing circuit in an inverter device. In FIG. 4, 1 is a DC power supply, 2 is a fuse, and 3 is six IGBTs.
Inverter section composed of a transistor and a freewheeling diode, 4 is a primary winding of a pulse transformer, 5 is an N-channel MOS-FET, 6 is a resistor for detecting a drain current flowing through N-channel MOS-FET 5, 8 is a motor, and 9 is an inverter. An IGBT transistor ON / OFF drive circuit section of section 3, a pulse transformer secondary-side voltage rectification diode, 11 a pulse transformer secondary-side voltage smoothing capacitor, 12 a pulse transformer secondary-side winding, and 13 an N On / off drive and pulse transformer secondary side voltage control circuit unit having a drain current overcurrent detection cutoff function of channel MOS-FET5, 14 is a gate resistance for driving the N-channel MOS-FET5, and 15 and 16 are N-channel MOS-
Reference numeral 17 denotes an RC filter resistor and a filter capacitor for detecting a drain current flowing through the FET 5 and a circuit portion for detecting a secondary voltage of the pulse transformer (a voltage between terminals of the smoothing capacitor 11) and transmitting a detected voltage. The occurrence of the secondary disaster of the inverter device from the short-circuit current when the semiconductor switching element group of the inverter unit 3 is short-circuited and broken is prevented by blowing the fuse 2, and similarly, the N-channel M
The occurrence of a secondary disaster of the inverter device due to a short-circuit current when the OS-FET 5 is short-circuit-damaged is also prevented by blowing the fuse 2.

FIG. 5 shows a second configuration example of a conventional fuse blowing circuit in an inverter device. 5, the configurations 1 to 17 are the same as those in FIG. Further, the configuration differs from the configuration in FIG. 4 in that a fuse 19 is provided.
In this case, the short-circuit current in the case where the semiconductor switching element group of the inverter unit 3 is short-circuit-damaged is used to determine the inverter device
Prevent the next disaster from occurring by blowing the fuse 2,
The fuse 19 prevents the occurrence of secondary disaster of the inverter device due to the short-circuit current when the N-channel MOS-FET 5 is short-circuited and damaged.

FIG. 6 shows a third configuration example of a conventional fuse blowing circuit according to Japanese Patent Publication No. 7-83590. 6, 101 is a commercial AC power supply, 102 is a current fuse,
103 is a rectifying / smoothing circuit, 104 is a high-frequency transformer, 10
5 is a switching transistor, 106 is an overcurrent detection resistor, 107 is a protection circuit, 108 is a base drive low voltage circuit, 109 is a secondary side rectifying and smoothing circuit, 110 and 111 are output terminals, and 112 is a short circuit current. . Switching transistor 105 base and overcurrent detection resistor 106
A protection circuit 107 composed of a series connection of diodes is connected in parallel between the rectifying and smoothing circuit 103 and the side connected to the negative electrode, and the anode side of the series connection of the diodes is connected to the base of the switching transistor 105. Connected. If the switching transistor 105 is short-circuited and damaged, the short-circuit current 112 is supplied to the protection circuit 107 composed of a series connection of the high-frequency transformer 104, the switching transistor 105, and the diode until the current fuse 102 is blown, as shown in FIG. The base voltage of the switching transistor 105 can be clamped by the total forward voltage of the series connection of diodes, so that the base driving low voltage circuit 108 connected to the base of the switching transistor 105 can be protected.
Prevent the occurrence of the next disaster.

[0005]

In FIG. 4, which is the above-mentioned conventional structure, both when the semiconductor switching element group of the inverter unit 3 is short-circuited and damaged and when the N-channel MOS-FET 5 is short-circuited and damaged,
In each case, the fuse 2 is blown to prevent the occurrence of a secondary disaster of the inverter device. However, when the N-channel MOS-FET 5 is short-circuited and damaged when the semiconductor switching element group of the inverter unit 3 is short-circuited and damaged, the winding resistance of the primary winding 4 of the pulse transformer and the N-channel MOS- Since the short-circuit current value is suppressed by the drain current detecting resistor 6 flowing through the FET 5, the fusing of the fuse 2 is slowed down. In addition, since the voltage between the terminals of the drain current detecting resistor 6 increases, the There is also a problem such as burnout or burnout of the RC filter resistor 15 and the filter capacitor 16 connected to the resistor. In order to shorten the fusing time of the fuse 2, the current rating value of the fuse may be reduced, but in such a case, the load of the inverter device cannot be increased.

FIG. 5 shows a configuration example which solves this problem. The fuse 2 is used for protection in the case where the semiconductor switching element group of the inverter unit 3 is short-circuited and damaged.
The protection in the case where the N-channel MOS-FET 5 is short-circuited and broken is provided with a fuse 19, and the rated current value of the fuse 19 is reduced to solve the problem in the configuration example of FIG. However, this FIG.
In this configuration, since two fuses having greatly different capacities are used, there is a problem that the cost is increased. FIG.
The protection circuit 107 composed of a series connection of diodes in the above-described conventional configuration example has a problem that it cannot be applied to a MOS-FET transistor requiring a high voltage value for ON driving.

SUMMARY OF THE INVENTION Accordingly, the present invention is to solve the above-mentioned conventional problems.
In any case where the semiconductor switching element of the DC / DC converter is short-circuited and damaged, it is possible to prevent the secondary disaster of the inverter device due to the quick blow of the fuse, and to use an inexpensive configuration for the DC / DC converter. It is an object of the present invention to provide a fuse blowing circuit for an inverter device realized by a configuration that does not select a semiconductor switching element.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a DC power supply, a fuse connected in series to the DC power supply, and a parallel connection of a series connection of the DC power supply and the fuse. An inverter unit composed of a group of semiconductor switching elements, a pulse transformer having one end of a primary winding connected to a positive electrode side of a series connection of the DC power supply and the fuse, and a primary winding of the pulse transformer A semiconductor switching element having an output terminal connected to the other end thereof, and a resistance element connected between the negative electrode side of the series connection of the DC power supply and the fuse and the other output terminal of the semiconductor switching element. An inverter device comprising a DC / DC converter provided with an anode connected to a connection point between the resistance element and the semiconductor switching element. It is characterized by comprising a series connection of one or more diodes connected to the cathode side to the anode side of the series connection of the fuse and. The series connection of one or more diodes is replaced with a constant voltage diode, and the cathode side of the constant voltage diode is connected to a connection point between the resistance element and the semiconductor switching element, and the anode side of the constant voltage diode is connected. Is connected to a negative electrode side of a series connection body of the DC power supply and the fuse.

[0009]

FIG. 1 shows the structure of a first embodiment of the present invention. In FIG. 1, 1 is a DC power supply, 2 is a fuse,
Reference numeral 3 denotes an inverter unit composed of six IGBT transistors and a freewheeling diode, 4 denotes a primary winding of a pulse transformer, 5 denotes an N-channel MOS-FET, 6 denotes a resistor for detecting a drain current flowing through the N-channel MOS-FET 5, 7
a and 7b are diodes, 8 is a motor, 9 is an IGBT transistor ON / OFF drive circuit of the inverter unit 3,
10 is a diode for voltage rectification on the secondary side of the pulse transformer, 1
1 is a capacitor for smoothing the voltage on the secondary side of the pulse transformer;
Is the secondary winding of the pulse transformer, and 13 is the N-channel MO.
On / off drive and pulse transformer secondary side voltage control circuit section having a drain current overcurrent detection cutoff function of S-FET5, 14 is a gate resistance for driving the N-channel MOS-FET5, and 15 and 16 are N-channel MOS. -FET5
Reference numeral 17 denotes a pulse transformer secondary-side voltage (a voltage between terminals of the smoothing capacitor 11) and a detection voltage transmission circuit unit.

FIG. 2 is a circuit diagram of the N-channel MOS transistor shown in FIG.
On / off drive / pulse transformer secondary voltage control circuit unit 13 having a drain current overcurrent detection / cutoff function of FET 5 and pulse transformer secondary voltage (voltage between terminals of smoothing capacitor 11) detection and detection voltage transmission Circuit section 17
Is specifically shown. The DC / DC converter section includes a secondary voltage of the pulse transformer (the smoothing capacitor 11).
Between the terminals of the resistor 72 in the detection and detection voltage transmission circuit unit 17 and the N-channel MOS-FET 5
In order to match the reference voltage 32 for the on / off driving and the voltage control circuit section 13 on the secondary side of the pulse transformer provided with the drain current overcurrent detection cutoff function of
-Controls the ON time width of FET5. Further, the drain current is detected from the voltage between the terminals of the resistor 6 after passing through the RC filter of the resistor 15 and the capacitor 16, and this detected voltage value (detected drain current value) is used as the reference voltage 38 for overcurrent detection. When it exceeds, the MOS-FET 5 is turned off instantaneously via the comparator 37, the RS flip-flop 36, and the NOR gate 39, and the ON / OFF oscillation frequency of the MOS-FET 5 (the triangular wave is input to the comparison input terminal of the comparator 35). After the elapse of one cycle time (which is made by inputting a voltage), the cutoff operation is released by the comparator 35, the RS flip-flop 36, and the NOR gate 39 so that the drain current is kept within the overcurrent detection level, and The secondary voltage is controlled.

The rated current value of the fuse 2 is selected according to the load capacity of the inverter. First, when short-circuit breakage occurs in the inverter section 3, there is almost no resistance for limiting the short-circuit current, and therefore a large short-circuit current flows through the fuse 2, so that the fuse can be blown instantaneously. When the MOS-FET 5 in the converter section is short-circuit-damaged, most of the short-circuit current passes through the diodes 7a and 7b in the initial stage of the short-circuit (the diode 7 is connected to the resistor 6).
After the diodes 7a and 7b are damaged by the short-circuit mode, all the short-circuit currents flow through the diodes 7a and 7b.
a and 7b, the short-circuit current is limited only by the winding resistance of the primary winding 4 of the pulse transformer. Since the primary winding 4 of this pulse transformer has a small winding resistance, a large short-circuit current
Flow and blow the fuse instantaneously.

FIG. 3 shows the configuration of a second embodiment of the present invention. 3, only the diodes 7a and 7b in FIG. 1 are replaced by constant voltage diodes 18 in the configuration example of FIG. 1, and other configurations are the same. In this case, when the MOS-FET 5 of the converter section is short-circuit-damaged, most of the short-circuit current passes through the constant-voltage diode 18 at the initial stage of the short-circuit (the constant voltage of the constant-voltage diode 18 is applied to the resistor 6). After the constant voltage diode 18 is damaged by the short-circuit mode, all the short-circuit current flows through the constant-voltage diode 18. Therefore, the short-circuit current is limited by the primary winding 4 of the pulse transformer. Only the winding resistance. Since the winding resistance of the primary winding 4 of this pulse transformer is small, a large short-circuit current flows through the fuse 2 and the fuse can be blown instantaneously.

In the configuration according to the first aspect, the rated current value of the fuse connected in series to the DC power supply is selected according to the load capacity connected to the output terminal of the inverter device. Therefore, when a short circuit breakage of the semiconductor switching element group occurs in the inverter section including the semiconductor switching element group connected in parallel to the series connection of the DC power supply and the fuse, the resistance that limits the short circuit current is almost zero. Since there is no short-circuit current, a sufficient current sufficient to blow the fuse can be secured, so that the secondary blow of the inverter device can be prevented by the quick blow of the fuse.

When the semiconductor switching element connected to the primary winding of the pulse transformer in the DC / DC converter section is short-circuited and damaged, the short-circuit current is applied to the primary winding of the pulse transformer and the short-circuited semiconductor. The current flows sequentially to a series connection of one or more diodes having a cathode connected to the negative side of the series connection of the switching element, the DC power supply and the fuse. Therefore, the terminal-to-terminal voltage value of the resistance element connected between the negative electrode side of the series connection of the DC power supply and the fuse and the output terminal of the semiconductor switching element is the total forward voltage of the series connection of the diodes. It will be clamped. After this state lasts for a while (extremely short time), the series connection of the diodes becomes (shorter current × total forward voltage) for the duration.
Damage caused by short-circuit mode. After this series connected diode is damaged by the short-circuit mode,
Since the voltage between the terminals of the resistance element is clamped to zero, even if a short-circuit current flows as it is, the resistance of the resistance, the resistance of another resistance connected to the resistance, or the damage of the capacitor does not occur. Similarly, the voltage between the terminals of the series connection of the diode that has been short-circuited and broken is also zero, so that the loss generated in the series connection of the diode is eliminated, and therefore, the short-circuit current (the short-circuit since the fuse has started to be blown) (The current is sharply reduced.). Here, in both cases before and after breakage of the series connection of the diodes, the only thing that limits the short-circuit current is the primary winding resistance of the pulse transformer, and this resistance value is generally small. Since the value is a value, a short-circuit current sufficient to blow the fuse can be secured, so that a secondary disaster of the inverter device can be prevented from occurring due to the quick blow of the fuse.

Here, the series connection of one or more diodes is used because the negative side of the series connection of the DC power supply and the fuse and the semiconductor switching element during normal operation of the DC / DC converter section. When the forward voltage value of the diode is lower than the voltage value between the terminals of the resistance element generated by the current flowing through the semiconductor switching element, the DC / D
Since it interferes with the normal operation of the C converter,
Therefore, in order to prevent this interference, the diode is connected in series so that the total forward voltage (hereinafter referred to as the diode clamping voltage) is set to be always larger than the voltage between the terminals of the resistor. Further, in the configuration according to claim 2, the series connection of the diodes is replaced with a constant voltage diode, and a cathode side of the constant voltage diode is connected to a connection point between the resistance element and the semiconductor switching element. Of the DC power supply and the fuse is connected to the negative electrode side of a series connection body of the DC power supply and the fuse.
The constant voltage value of the constant voltage diode corresponds to the diode clamp voltage in the configuration of the first aspect.

According to the second aspect of the present invention, if the semiconductor switching element connected to the primary winding of the pulse transformer is short-circuited and damaged in the DC / DC converter, the short-circuit current is reduced to the primary current of the pulse transformer. The current flows sequentially to the side winding, the short-circuit damaged semiconductor switching element, and the constant voltage diode. Therefore, the voltage value between the terminals of the resistance element connected between the negative electrode side of the series connection of the DC power supply and the fuse and the output terminal of the semiconductor switching element is clamped by the constant voltage value of the constant voltage diode. Will be. After this state lasts for a while (extremely short time), the constant voltage diode is damaged by the short circuit mode due to the loss caused by (short circuit current × constant voltage value) during the above period. After the constant voltage diode is damaged by the short-circuit mode, the voltage between the terminals of the resistance element is clamped to zero. Therefore, even if the short-circuit current flows as it is, the resistance is burned out, or another resistance connected to the resistance is connected. No resistance or capacitor burnout occurs. Similarly, the voltage between the terminals of the short-circuit damaged constant voltage diode becomes zero, so that no loss occurs in the constant voltage diode. Therefore, the short-circuit current thereafter (the short-circuit current sharply increases because the fuse has started to blow). ) In the series connection of the diodes. Here, in both cases before and after breakage of the series connection of the diodes, the only thing that limits the short-circuit current is the primary winding resistance of the pulse transformer, and this resistance value is generally small. Since the value is a value, a short-circuit current sufficient to blow the fuse can be secured, so that a secondary disaster of the inverter device can be prevented from occurring due to the quick blow of the fuse.

[0017]

As described above, according to the present invention, both when the semiconductor switching element group of the inverter unit in the inverter unit is short-circuited and damaged and when the semiconductor switching element of the DC / DC converter unit is short-circuited and damaged. There is an effect that it is possible to prevent a secondary disaster of the inverter device by quickly blowing the fuse, and to realize the same at a low cost by using a single fuse configuration.

[Brief description of the drawings]

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

FIG. 2 is a partial detailed configuration diagram according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram of a fuse blowing circuit of an inverter device according to a second embodiment of the present invention.

FIG. 4 is a first configuration diagram of a fuse blowing circuit of an inverter device in a conventional example.

FIG. 5 is a second configuration diagram of a fuse blowing circuit of the inverter device in the conventional example.

FIG. 6 is a third configuration diagram of a fuse blowing circuit of an inverter device in a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 DC power supply 2 Fuse 3 Inverter part consisting of six IGBT transistors and a freewheeling diode 4 Primary winding of pulse transformer 5 N-channel MOS-FET 6 Drain current detection resistors 7a, 7b diodes flowing through N-channel MOS-FET5 Reference Signs List 8 Motor 9 ON / OFF drive circuit section of IGBT transistor of inverter section 3 10 Pulse transformer secondary side voltage rectification diode 11 Pulse transformer secondary side voltage smoothing capacitor 12 Pulse transformer secondary side winding 13 N-channel MOS-FET5 And a pulse transformer secondary-side voltage control circuit unit 14 having a drain current overcurrent detection cut-off function and a gate resistance for driving the N-channel MOS-FET 5 15 For detecting a drain current flowing through the N-channel MOS-FET 5 RC file Capacitor resistor 16 N-channel MOS-FET 5 the drain current RC filter capacitor 17 pulse transformer secondary voltage for detecting flowing (smoothing capacitor 1
Circuit for detecting and transmitting detected voltage 18) Constant voltage diode 19 Fuse 31 Resistor 32 Voltage control reference voltage 33 Operational amplifier 34a Upper transistor for gate drive of MOS-FET5 34b Lower stage for gate drive of MOS-FET5 Side transistor 35 Comparator 36 RS flip-flop 37 Comparator 38 Overcurrent detection reference voltage 39 NOR gate 71, 72 Resistance 101 Commercial AC power supply 102 Current fuse 103 Rectifier smoothing circuit 104 High frequency transformer 104a Primary winding of high frequency transformer 104b High frequency Transformer secondary winding 105 Switching transistor 106 Overcurrent detection resistor 107 Protection circuit 108 Base drive low voltage circuit 109 Secondary side rectification and smoothing circuit 110, 111 Output terminal 112 Short Fault current

Claims (2)

[Claims] An inverter unit including a DC power supply, a fuse connected in series to the DC power supply, and a semiconductor switching element group connected in parallel to a series connection of the DC power supply and the fuse; A pulse transformer in which one end of a primary winding is connected to a positive electrode side of a series connection of a power supply and the fuse; and a semiconductor switching element in which an output terminal is connected to the other end of the primary winding of the pulse transformer. An inverter device comprising a DC / DC converter unit having a resistance element connected between a negative electrode side of a series connection body of the DC power supply and the fuse and the other output terminal of the semiconductor switching element. An anode is connected to a connection point between the resistance element and the semiconductor switching element, and a cathode is connected to a negative side of a series connection body of the DC power supply and the fuse. Fuse circuit of an inverter apparatus comprising the series connection of one or more diodes connected to over de side. 2. A constant voltage diode, wherein the series connection of one or more diodes is replaced by a constant voltage diode, and a cathode side of the constant voltage diode is connected to a connection point between the resistance element and the semiconductor switching element. 2. The fuse blowing circuit of claim 1, wherein an anode of the diode is connected to a negative electrode of a series connection of the DC power supply and the fuse.