48results about How to "Reduce the number of capacitors" patented technology

The invention discloses a modular multilevel dynamic switching DC-DC transformer which is composed of N DC-DC sub modules connected in series. Each DC-DC sub module is a symmetric structure which is composed of two half-bridge sub modules and isolating switches S1 and S2 arranged between the two sub modules and can realize bidirectional power flow. Capacitors C1 and C2 are arranged in parallel between the half-bridge sub modules and the isolating switches. The power input end is used as the primary side of the DC-DC transformer, and the power output end is used as the secondary side of the DC-DC transformer. The half-bridge sub modules are primary sub modules when on the primary side of the DC-DC transformer, and are secondary sub modules when on the secondary side of the DC-DC transformer. The primary and secondary sub modules are switched on or off by turning on or off a switching device. Compared with the prior art, the switching ratio of primary to secondary sub modules can be changed dynamically; the transmission power can be controlled flexibly, and the DC-DC transformer has DC power flow control ability; and the number of sub modules is greatly reduced, the advantage of economical performance is significant, the size of the DC-DC transformer is reduced, and the DC-DC transformer can be easily promoted and applied.

The invention discloses a resonant double power supply aviation electromagnetic launching device. The high-power main circuit module includes an AC generator set, a DC airborne power supply, a power conversion main circuit, a resonant main circuit and a transmitting circuit; the AC generator set and the DC airborne The power supply is connected in parallel to the main circuit of the power conversion, and the main circuit of the power conversion converts the direct current of the airborne power supply or the alternating current of the generator set into high-frequency alternating current through the high-frequency inverter bridge or controllable rectifier bridge-high-frequency inverter bridge, and the high-frequency alternating current is passed through The high-frequency uncontrolled rectifier bridge is converted into direct current, and the direct current is converted into an AC square wave by the half bridge; the power conversion main circuit is connected with the resonant main circuit, and the resonant main circuit converts the AC square wave into a sine wave with a fixed resonant frequency; the resonant main circuit It is connected with the transmitting circuit, and the electromagnetic wave of the required transmitting frequency and waveform is transmitted through the transmitting circuit. The invention adopts the mode of parallel power supply to reduce the capacity, weight and volume of the hoisting alternator.

The invention provides a half-bridge modular multi-level single-phase inverter and a modulation method, comprising: a capacitor bridge arm and a modular multi-level bridge arm; the modular multi-level bridge arm includes: two ports sub-module; the capacitor bridge arm and the modular multilevel bridge arm each include a DC positive terminal, a DC negative terminal and an AC terminal; the DC positive terminal of the capacitor bridge arm and the modular multilevel terminal The DC positive terminal of the bridge arm is connected to the positive terminal of the DC power supply; the DC negative terminal of the capacitor bridge arm is connected to the DC negative terminal of the modular multi-level bridge arm and is connected to the negative terminal of the DC power supply The AC terminal of the bridge arm of the capacitor and the AC terminal of the modular multi-level bridge arm together constitute the AC output port of the single-phase inverter. The novel nearest-level approximation modulation strategy proposed by the present invention for the topology can realize accurate topology output and maintain the effective operation of the system.