Method, power unit, and power system having gate voltage limiting circuit

A power unit, comprising:

• a solid-state switch having a control terminal and first and second power terminals;
• a drive circuit remotely connected to the control terminal for controllably activating the switch;
• and
• a clamping circuit electrically coupled between the control terminal and one of the first or second power terminals, wherein the clamping circuit is configured to limit a voltage across the control terminal and said one of the first or second power terminals to a voltage level that is above a turn-on voltage of the switch and below a maximum voltage of the switch.

A power system, comprising:

• an inverter module controllable to generate an alternating-current output waveform for driving a motor, the inverter module comprising a clamping circuit and a transistor switch contained within a switch housing;
• and
• a drive circuit operatively coupled to the transistor switch through a first wire lead coupling a first terminal of the drive circuit to a gate terminal of the transistor switch and a second wire lead coupling a second terminal of the drive circuit to an emitter terminal of the transistor switch;
• wherein the clamping circuit is disposed in parallel with the transistor switch between the gate terminal and the emitter terminal for limiting a voltage across the gate and emitter terminals, and wherein the clamping circuit is disposed inside the switch housing or on an outer surface of the switch housing.

A power unit comprising:

• a transistor switch electrically coupleable to a remotely-mounted drive circuit through two or more first wire leads;
• and
• a clamping circuit electrically coupled to first and second terminals of the transistor switch and configured to limit a voltage across the first and second terminals of the transistor switch, wherein the clamping circuit comprises:
• a first set of parallel-connected diodes connected to one of the first terminal or the second terminal;
• and one of:
• at least one capacitor connected in series with the first set and connected to the other of the first terminal of the second terminal;
• or
• a second set of diodes connected in series with the first set and connected to the other of the first terminal or the second terminal.

A method comprising:

• applying a first voltage signal to a control terminal of a first transistor of an inverter module to generate an alternating-current output waveform;
• upon the first transistor transitioning from an on-state to an off-state, limiting a voltage between the control terminal and a power terminal of the first transistor to less than a voltage that would damage the first transistor, wherein the voltage between the control terminal and the power terminal of the first transistor is limited by a first clamping circuit electrically connected between the control terminal and the power terminal of the first transistor;
• and
• blocking current through the first clamping circuit when the first transistor is negatively biased between the control terminal and the power terminal above a first threshold.