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Fast charging of high-capacity battery packs contributes to more disruptions in ac-powered systems, thereby increasing the demand for intelligent converters that are both efficient and low in distortion. Therefore, it is crucial to have a battery charger that can respond to the battery's current condition and modify the charging procedure accordingly. To accommodate a wide battery voltage range in on-board battery charger (OBC) applications utilizing LLC resonant converters, a hybrid control technique that combines pulse-frequency modulation (PFM) with phase-shift modulation (PSM) has been proposed. It is. assumed that the input voltage of the LLC converter experiences a 100-Hz fluctuation as a result of power factor correction at the front-end power rectifier. When the control modes change between PSM and PFM due to input voltage fluctuations, a surge current is observed in the output current, which causes heat generation and battery deterioration. In addition to that, a change in the output gain of the main circuit has been confirmed. To mitigate this issue, a novel control state transition strategy known as overlapping mode of operation is proposed for the LLC resonant converters employing PSM and PFM. The experimental findings validated the reduction in surge current and showed that the proposed control method is effective in comparison to the conventional hybrid method.

HILS (Hardware-In-the-Loop Simulation) of SMPSs (Switched-Mode Power Supplies) requires a high real-time simulation capability for the power stage emulator. However, it is difficult to emulate the high-frequency switching operation of SMPSs in real-time. Thus, a technique has been proposed to make HILS of SMPSs possible by using an averaged model that does not include switching operations. However, the LLC resonant converter dealt with in this paper, cannot easily acquire this averaged model. In the past, our research team proposed the modeling method for LLC resonant converter in the form of a small-signal linearized model using circuit simulation. However, this model cannot express the wide operating range required by HILS. In this paper, by extending this small-signal linearized model to the LPV model, we propose the averaged model for LLC resonant converter that can express a wide operating range. In addition, we construct an actual HILS system using this averaged model for the LLC resonant converter and verify the validity of the model and the feasibility of HILS by comparing it with a real circuit.

In the past, arms used in the fields of industry and robotics have been designed not to vibrate by increasing their mass and stiffness. The weight of arms has tended to be reduced to improve speed of operation, and decrease the cost of their production. Since the weight saving makes the arms lose their stiffness and therefore vibrate more easily, the vibration suppression control is needed for realizing the above purpose. Incidentally, the use of various smart materials in actuators has grown. In particular, a shape memory alloy (SMA) is applied widely and has several advantages: light weight, large displacement by temperature change, and large force to mass ratio. However, the SMA actuators possess hysteresis nonlinearity between their own temperature and displacement obtained by the temperature. The hysteretic behavior of the SMA actuators affects their control performance. In previous research, an operator-based control system including a hysteresis compensator has been proposed. The vibration of a flexible arm is dealt with as the controlled object; one end of the arm is clamped and the other end is free. The effectiveness of the hysteresis compensator has been confirmed by simulations and experiments. Nevertheless, the feedback signal of the previous designed system has increased exponentially. It is difficult to use the system in the long-term because of the phenomenon. Additionally, the SMA actuator generates and radiates heat because electric current passing through the SMA actuator provides heat, and strain on the SMA actuator is generated. With long-time use of the SMA actuator, the environmental temperature around the SMA actuator varies through radiation of the heat. There exists a risk that the ambient temperature change dealt with as disturbance affects the temperature and strain of the SMA actuator. In this research, a design method of the operator-based control system is proposed considering the long-term use of the system. In the method, the hysteresis characteristics of the SMA actuator and the temperature change around the actuator are considered. The effectiveness of the proposed method is verified by simulations and experiments.