Inverter device and electric motor device using same
The object of the invention is to provide an inverter device and an electric motor device using the same to shorten a dead time. Thus, an inverter device is provided, which includes: a switching element including a control terminal and a pair of main terminals; a control circuit configured to output a control signal which indicates whether to instruct an ON state of the switching element; a decision circuit configured to output a decision signal which indicates a state of the switching element based on a voltage between the main terminals of the switching element; and a drive circuit configured to control the ON state or an OFF state of the switching element based on the control signal and the decision signal.
1. An inverter device comprising:
a switching element including a control terminal and a pair of main terminals;
a control circuit configured to output a control signal which indicates whether to instruct an ON state of the switching element;
a decision circuit configured to output a decision signal which indicates a state of the switching element based on a voltage between the main terminals of the switching element; and
a drive circuit configured to control the ON state and an OFF state of the switching element based on the control signal and the decision signal;
wherein the drive circuit includes an OR circuit configured to input the control signal and the decision signal as logical signals and output a logical sum of the control signal and the decision signal.
2. The inverter device according to claim 1 , wherein
the decision signal is a signal indicating whether to instruct the ON state of the switching element, and
the drive circuit is configured to set the switching element into the ON state when at least one of the control signal and the decision signal instructs the ON state.
3. The inverter device according to claim 2 , wherein
the switching element contains SiC as a semiconductor material.
4. The inverter device according to claim 2 , wherein
in the decision circuit, a first level of the voltage between the main terminals at which the decision signal shifts from a state where no ON state of the switching element is instructed to a state where the ON state of the switching element is instructed, and a second level of the voltage between the main terminals at which the decision signal shifts from the state where the ON state of the switching element is instructed to the state where no ON state of the switching element is instructed are equal.
5. The inverter device according to claim 1 , wherein
the switching element is a MOSFET.
6. The inverter device according to claim 1 , wherein
a plurality of switching elements are provided, and
the decision circuit is provided for each of the switching element.
7. The inverter device according to claim 1 , wherein
the switching element is provided between a direct current power source and a load device and is configured to perform a rectification operation when electric power is regenerated from the load device to the direct current power source, and
the control circuit has a function of stopping level control over the control signal when the switching element performs the rectification operation.
8. The inverter device according to claim 1 , wherein
the drive circuit further includes a driver circuit configured to drive the control terminal of the switching element based on an output signal of the OR circuit.
9. The inverter device according to claim 8 , wherein
the driver circuit is configured to drive the control terminal such that a speed at which the switching element is switched from the ON state to the OFF state is faster than a speed at which the switching element is switched from the OFF state to the ON state.
10. The inverter device according to claim 1 , wherein
the decision circuit is a comparator configured to compare voltages of the pair of main terminals.
11. The inverter device according to claim 1 , further comprising:
a voltage step-down circuit inserted between one of the main terminals of the switching element and the decision circuit and configured to apply a voltage lower than the voltage between the main terminals to the decision circuit.
12. An electric motor device comprising:
an inverter device; and
a motor driven by the inverter device, wherein the inverter device includes:
a switching element including a control terminal and a pair of main terminals;
a control circuit configured to output a control signal which indicates whether to instruct an ON state of the switching element;
a decision circuit configured to output a decision signal which indicates a state of the switching element based on a voltage between the main terminals of the switching element; and
a drive circuit configured to control the ON state and an OFF state of the switching element based on the control signal and the decision signal;
wherein the drive circuit includes an OR circuit configured to input the control signal and the decision signal as logical signals and output a logical sum of the control signal and the decision signal.
13. An inverter device comprising:
a switching element including a control terminal and a pair of main terminals;
a control circuit configured to output a control signal which indicates whether to instruct an ON state of the switching element;
a decision circuit configured to output a decision signal which indicates a state of the switching element based on a voltage between the main terminals of the switching element; and
a drive circuit configured to control the ON state and an OFF state of the switching element based on the control signal and the decision signal; wherein
the switching element is provided between a direct current power source and a load device and is configured to perform a rectification operation when electric power is regenerated from the load device to the direct current power source, and
the control circuit has a function of stopping level control over the control signal when the switching element performs the rectification operation.
14. An inverter device comprising:
a switching element including a control terminal and a pair of main terminals;
a control circuit configured to output a control signal which indicates whether to instruct an ON state of the switching element;
a decision circuit configured to output a decision signal which indicates a state of the switching element based on a voltage between the main terminals of the switching element;
a drive circuit configured to control the ON state and an OFF state of the switching element based on the control signal and the decision signal; and
a voltage step-down circuit inserted between one of the main terminals of the switching element and the decision circuit and configured to apply a voltage lower than the voltage between the main terminals to the decision circuit.