Hella Kgaa Hueck and Company

Hella Gmbh & Co Kgaa

Hella Corporate Center Usa, Inc.

Juncheng Lu

Hua Bai

Hui Teng

An AC/DC conversion apparatus includes first, second, and third AC/DC conversion modules operated by a controller in two modes of operation. In the first mode, the input AC signal is 3-phase and each of the three modules are enabled to handle a respective one of the input phases. In the second mode, the input AC signal is single phase and the first and second modules are enabled to deliver output power based on the single-phase AC input, while the controller actuates an H-bridge switches in the third module to which active filter circuitry is connected, to reduce an AC component in the output signal. The active filter circuitry can be selectively connected to the H-bridge switches when single-phase operation is desired, which circuitry may be disposed in a filter housing having male electrical terminals that cooperate with corresponding female terminals associated with the third module.

Electric power conversion apparatus having single-phase and multi-phase operation modes

A hybrid switch apparatus includes a gate drive circuit producing a gate drive signal, a GaN high electron mobility transistor (HEMT) having a first gate, a first drain, and a first source. A silicon (Si) MOSFET has a second gate, a second drain, and a second source. The GaN HEMT and the Si MOSFET are connected in a parallel arrangement so that (i) the first drain and the second drain are electrically connected and (ii) the first source and the second source are electrically connected. The second gate is connected to the gate drive circuit output to receive the gate drive signal. A delay block has an input connected to the gate drive circuit output and an delay block output is configured to produce a delayed gate drive signal for driving the GaN HEMT.

Hybrid switch including GaN HEMT and MOSFET

A single-phase AC/DC electric power conversion apparatus includes an indirect matrix converter having an input interface to receive a first alternating current (AC) signal and an output interface to produce a second AC signal, where the first AC signal has a grid frequency. A transformer has a primary winding and an electrically isolated and magnetically coupled secondary winding. A coupling inductor is connected in series between the output interface of the indirect matrix converter and the primary winding. An H-bridge switching arrangement is connected to the secondary winding and produces an output signal having a DC component and at least one AC component. The at least one AC component has a second order harmonic of the grid frequency. An active filter reduces the second order harmonic AC component. A modular conversion apparatus for three-phase power replicates the single-phase apparatus as a module for each phase and omits the active filter.

Electric power conversion apparatus with active filter

An apparatus includes a gate drive circuit and a GaN HEMT switch where the gate drive circuit has a gate drive output to produce a gate drive signal in response to a gate control signal. The switch has a gate connected to the gate drive circuit through a gate drive resistor. The gate drive circuit includes a NPN (or NMOS) turn-on transistor and a PNP (or PMOS) turn-off transistor. The gate drive circuit includes a turn-on resistor with a first resistance coupled to the turn-on transistor and a turn-off resistor with a second resistance coupled to the turn-off transistor. The turn-on and turn-off transistors, gate drive resistor, the switching device, but not the turn-on and turn-off resistors are disposed in an integrated circuit to reduce a gate-drive loop inductance. The first and second resistances can be different to adjust the turn-on and turn-off speeds of the switching device.

Gate drive circuit for power conversion apparatus

A driver circuit has a gate drive terminal that produces a gate drive signal to control paralleled power semiconductor switches, such as GaN high electron mobility transistor (HEMT) devices. One of the switches is closest to the gate drive terminal such that its gate drive loop inductance is smaller than the remaining switches that are farther away having a larger loop inductance. An additional resistor or gate-source capacitor is provided in the gate drive circuit of the closest switch which increases the total gate resistance of the closest switch compared to the remaining switches, which delays the turn off time of the closest switch. The delay permits zero voltage switching turn-off of the remaining switches to reduce noise. The closest switch is hard switched off but has the smallest loop inductance, which allows optimized turn off.

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Flint, MI, United States of America

Juncheng Lu