2618results about How to "Reduce switching losses" patented technology

An inverter circuit allowing a single drive circuit to perform both tracking control for tracking resonance frequency fluctuations caused by load fluctuations, and power control, thereby reducing switching loss. An inverter drive circuit part obtains a phase difference between output current and output voltage directed to a load circuit connected to a midpoint of two arm circuits of the inverter circuit, and controls a phase of the driving signal directed to each semiconductor switch such that the phase difference becomes zero or a predetermined value, enabling an operating frequency of the inverter circuit part to track a resonance frequency of the load circuit, and enabling a current phase to be delayed with respect to a voltage phase, thereby achieving ZCS. Since the phase difference is used, an auxiliary circuit is not necessary for measuring a current value in proximity to the semiconductor switches.

A switching power source comprises a current comparator 27 for comparing a voltage level of signals acquired by a current detector 9 with a reference voltage level VDT to produce detection signals VCP of first or second level L or H; an edge detector 28a for sensing an edge of drive signal VG supplied to a gate terminal of MOS-FET 3 during the period of transition from turning on to off of MOS-FET 3; and a decision means 28b for receiving a current detection signal VCP from current comparator 27 to produce an output signal VLD when edge detector 28a catches an edge of drive signal VG; wherein decision means 28b produces different output signals VLD of respectively first and second voltage levels L and H under the light and heavy load conditions to precisely and certainly detect on the primary side of transformer 2 the load condition on the secondary side of transformer 2 for improvement in conversion efficiency.

The invention discloses a submodule topology for a modular multi-level transverter. The submodule topology comprises a first switching module, a second switching module, a direct current capacitor and a third switching module, wherein the first switching module and the second switching module are connected in series, the negative end of the first switching module is connected with the positive end of the second switching module, and the first switching module and the second switching module are formed by connecting full-controlled devices and diodes in an antiparallel mode. The positive electrode and the negative electrode of the direct current capacitor are connected with the positive end of the first switching module and the negative end of the second switching module. The third switching module is electrically connected with the first switching module and the second switching module, so that a full-controlled device of the third switching module applies trigger pulses all the time during normal operation and is in a conducting state all the time, and currents of direct current faults can be blocked by locking the trigger pulses of the third switching module when direct current faults happen. The invention further comprises the transverter comprising a submodule and application of the transverter. By means of the submodule topology for the modular multi-level transverter and application of the modular multi-level transverter, a function of isolating the direct current faults is achieved, quantity and switching losses of switching devices in the submodule are decreased, and requirements on trigger simultaneity are reduced.