Murata Manufacturing Co., Ltd.

Yue Ma

Hitoshi Tsuji

Koichi Ueki

A Vfc balance controller includes a coefficient multiplying circuit that calculates a value of one half of a voltage, a subtractor, an adder, and a corrector. The adder adds a correction term V&#x3b1;&#xb7;sin to the output from the coefficient multiplying circuit. The subtractor calculates the difference between voltage Vfcof a flying capacitor and the output from the adder. The corrector outputs a correction time of a pulse width so that the output from the subtractor converges to zero. The voltage of the flying capacitor is varied in this manner to reduce ripples on a DC line.

Multi-stage DC-AC inverter

An energy management system that includes a power generating device, bidirectional DC-DC converter, and inverter connected to an HVDC bus. A gain of a voltage change to a current change in the bidirectional DC-DC converter is equal to the gain in the inverter. When an output power of the inverter or the bidirectional DC-DC converter varies in response to a variation in an output current of the power generating device, the energy management system can control the output power of the inverter to conform to a target value by adjusting an offset of gain characteristics of the bidirectional DC-DC converter to gain characteristics of the inverter. As a result, the energy management system is capable of stabilizing the output power of the inverter.

Energy management system

A three-level inverter circuit includes first to fourth front-stage switches connected in series, and a floating capacitor connected between a connection point of the first and second front-stage switches and a connection point of the third and fourth front-stage switch elements, and outputs an intermediate voltage of a DC power supply through a connection point of the second and third front-stage switches. A bridge circuit includes first, second, third, and fourth rear-stage switches which are bridge-connected to first to fourth terminals. The first terminal thereof is connected to a connection point of the second front-stage switch and the third front-stage switch and a second terminal thereof is connected to the second input terminal.

Growing community of inventors

Nagaokakyo, Japan

Yue Ma