Katsutoshi Yamanaka

A novel neutral point potential stabilization technique using the information of output current polarities and voltage vector

This paper proposes a new neutral point potential control technique for the three-level neutral-point-clamped PWM inverter. Utilizing the phase current polarity information, this technique distributes the redundant voltage vectors in a manner to obtain stable neutral point voltage under all operating conditions including the zero power factor condition. Detailed analysis and computer simulations show the superiority of the proposed method. The feasibility of the proposed method has been proven via laboratory experiments.

Bidirectional dc-ac conversion topology using matrix converter technique

The matrix converter is a power conversion topology, directly connecting the input and output with bidirectional switches. It has advantages such as high reliability and long life, bidirectional power flow and reduced current harmonics. This paper proposes a bidirectional dc-ac conversion topology with step-up and step-down capabilities using matrix converter technique. Detail of circuit operation and experimental results for various operating conditions will be described using a 1.0kW prototype.

Common-mode voltage reduction method of PWM current source inverter modifying the distribution of zero current vector

The common-mode voltage reduction method of the voltage source inverter has been studied extensively, but the studies for current-source inverter are less than that[1]. This paper proposes the new space vector PWM methods that can reduce the output common-mode voltage fluctuation of the PWM current source inverter. In the new PWM methods, the current source inverter output two nonzero current vectors and a zero current vector that has the minimum absolute value of common-mode voltage. The proposed method can reduce the amplitude of the common-mode voltage. This paper describes the principle of the proposed methods, the simulation results, and test results of experimental circuit.

Bidirectional DC-AC current source inverter using coupled inductor

This paper proposes a new current source inverter using a coupled inductor, which is derived from the circuit of the matrix converter using an additional inductor. The proposed circuit has the bidirectional power conversion ability, providing step-up and step-down operation in each direction, and can switch the direction of the power flow instantaneously. This paper describes the principle of operation, the simulation results and the experimental results of the proposed circuit.