Power conversion device, semiconductor switch drive device, and control method
A semiconductor switch drive device ( 3 ) includes a drive unit ( 10 ), a power supply unit ( 20 ), a switch ( 39 ), and a control unit ( 50 ). The drive unit ( 10 ) supplies a control signal to a semiconductor switch (Q) of a main circuit ( 2 ) and drives the semiconductor switch (Q). The power supply unit ( 20 ) supplies electric power to the drive unit ( 10 ). The switch ( 39 ) cuts off supply of electric power to the power supply unit ( 20 ) by detecting or controlling an overvoltage state on a primary side of the power supply unit ( 20 ). The control unit ( 50 ) switches a conductive state of the switch ( 39 ) on the basis of a voltage of a control terminal of the semiconductor switch (Q).
1. A semiconductor switch drive device comprising:
a drive circuit configured to supply a control signal to a semiconductor switch of a main circuit and drive the semiconductor switch;
a power supply circuit configured to supply electric power to the drive circuit;
a control circuit configured, by controlling, to switch a conductive state of the semiconductor switch on the basis of a voltage at a control terminal of the semiconductor switch; and
a gate power supply protection circuit including a second switch and configured to detect an overvoltage state and an undervoltage state on a primary side of the power supply circuit, and to cut off, by the second switch, supply of the electric power to the power supply circuit by detecting the overvoltage state, by detecting the undervoltage state, or by the controlling.
2. The semiconductor switch drive device according to claim 1 ,
wherein the drive circuit negatively biases the control signal when the semiconductor switch is turned off, and
wherein the control circuit causes the second switch to cut off the supply of the electric power to the power supply circuit if the voltage of the control terminal when the semiconductor switch is turned off is less than a prescribed value.
3. The semiconductor switch drive device according to claim 1 , wherein an output side of the power supply circuit is insulated from a power supply of the main circuit.
4. The semiconductor switch drive device according to claim 1 , wherein the semiconductor switch is an insulated gate bipolar transistor (IGBT).
5. The semiconductor switch drive device according to claim 1 , comprising a voltage detection circuit configured to detect the voltage of the control terminal of the semiconductor switch.
6. A power conversion device comprising:
a first main circuit including a first semiconductor switch that is controlled according to a first control signal supplied to a first control terminal;
a first drive circuit configured to supply the first control signal to the first control terminal and drive the first semiconductor switch;
a voltage detection circuit configured to detect a voltage of the first control terminal;
a second main circuit including a second semiconductor switch that is controlled according to a second control signal supplied to a second control terminal;
a second drive circuit configured to supply the second control signal to the second control terminal and drive the second semiconductor switch;
a power supply circuit configured to supply electric power to the first drive circuit and the second drive circuit;
a control circuit configured, by controlling, to switch a conductive state of the first semiconductor switch or the second semiconductor switch on the basis of a voltage at a control terminal of the first semiconductor switch or the second semiconductor switch; and
a gate power supply protection circuit including a third switch, configured to detect an overvoltage state and an undervoltage state on a primary side of the power supply circuit, and configured to cut off, by the third switch, supply of the electric power to the power supply circuit by detecting the overvoltage state, by detecting the undervoltage state, or by the controlling.
7. The power conversion device according to claim 6 , wherein the power supply circuit includes
a primary side circuit of the power supply circuit;
a first pulse transformer configured to convert electric power supplied from the primary side circuit and generate the electric power to be supplied to the first drive circuit; and
a second pulse transformer configured to convert the electric power supplied from the primary side circuit and generate the electric power to be supplied to the second drive circuit.
8. The power conversion device according to claim 6 , wherein the control circuit detects a short-circuit failure in the first semiconductor switch or the second semiconductor switch on the basis of the voltage of the first control terminal that has been detected.
9. A method of controlling a semiconductor switch drive device including a drive circuit configured to supply a control signal to a semiconductor switch of a main circuit and drive the semiconductor switch, a power supply circuit configured to supply electric power to the drive circuit, and a gate power supply protection circuit configured to detect an overvoltage state and an undervoltage state on a primary side of the power supply circuit, and configured to cut off, by a second switch, supply of the electric power to the power supply circuit either by detecting the overvoltage state, by detecting the undervoltage state, or by controlling, the method comprising:
switching a conductive state of the semiconductor switch by the controlling on the basis of a voltage at a control terminal of the semiconductor switch.