This paper proposes a passivity-based control method for an IPM motor drive system to ensure stability. The proposed method is based on the design of an additional feedforward (FF) compensation loop and relaxation of the pole of the PI compensation, which makes the frequency characteristics of the DC input impedances resistive or passive. The method utilizes an extended small-signal IPM model and analytical expressions considering FF compensation. The frequency characteristics of the proposed method, as determined by the impedance method, are investigated and confirmed to be passive. System stability is validated both analytically and experimentally.

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Previous researches proposed a system in which multiple PMSMs are driven in parallel by a single inverter, but this system is not suitable for applications requiring position control. To solve this problem, this study propose a system in which one inverter drives both rotor position-independent IM and dependent PMSM in parallel, and reported good results obtained by simulation.

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Among conducted EMI noise, it is difficult to identify the cause of high-frequency components in the 10-30MHz band, and countermeasures are an issue. In this study, we aim to confirm that the noise terminal voltage in the 10-30MHz band changes depending on the circuit layout of the NTC-TH, and to investigate the mechanism and propose the optimal circuit layout.

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The load-independent operation provides the constant output voltage and the soft switching against load variations. Because it is unnecessary to prepare the control construction, the designs of the resonant converter become simple and easy. This paper present designs of the load-independent class-E2 DC-DC converter. By showing the experimental result, we can confirm the validity of the design in this paper.

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Bidirectional isolated DC-DC converters enable bidirectional conversion of DC power, and since they use a transformer, they can be grounded and have excellent safety. Conventional one-pulse DAB type converters have achieved downsizing and high efficiency of transformers by increasing the frequency, but they have not been put into practical use for large-capacity power transmission of about MW due to the limitation of the iron core structure of the transformer. This paper proposes a new control scheme for DC-DC converters for large-capacity applications in which the output waveform of the inverter is a PWM wave.

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GaN-HEMTs are increasingly adopted in power conversion circuits as next-generation semiconductor devices. Compared to conventional Si-based FETs, GaN-HEMTs exhibit low threshold voltage and require high-speed operation, complicating gate drive circuit design. This study presents a compact half-bridge circuit achieving 1 MHz hard-switching operation using Texas Instruments' GaN half-bridge modules with integrated gate drivers. We implement and evaluate a buck-converter and a three-phase inverter with the GaN half-bridge modules. The experimental results demonstrate the feasibility of high-frequency switching applications with simplified circuit design through the use of integrated gate drive solutions.

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This paper proposes a simple and effective compensator for a control method of a three-phase sinusoidal　system with inevitable asymmetry parameters in the phases. It is based on a sinusoidal compensator for a　negative sequence component. First, using a basic three-phase asymmetry circuit, the generation principle　of the negative component is explained. Then, it is proposed how to cancel the component with the compensator.　The proposed compensator is applied to a basic and a grid inverter examples with phase asymmetry　parameters. The effectiveness of the proposed method is validated by simulation.

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Wireless power transfer has been extensively studied. However, in the configuration proposed by the authors using a Dual Active Bridge (DAB) type DC/DC converter, it was necessary to constantly synchronize the processors on both the transmitting and receiving sides, since power transmission was controlled by the phase of a single pulse. To solve this problem, we propose a system that combines a wireless coil with a single-phase PWM inverter, enabling operation without synchronizing the two processors by utilizing the fundamental wave and carrier frequency. Simulation results demonstrated favorable performance, which we report here.

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In this research, we proposed replacing of matrix converters in place of conventional distribution transformers as a measure against voltage fluctuations caused by distributed power supplies. However, there is a problem that the output voltage of the matrix converter oscillates at the resonant frequency of the output filter when the load fluctuates. Therefore, we proposed a resonance suppression method using a state observer and a state feedback method, and confirmed its effectiveness through simulations.

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