This paper proposes a modular battery management system for an electric motorcycle. The system not only can accurately measure battery voltage, charging current, discharging current, and temperature but also can transmit the data to the mixed-signal processor for battery module monitoring. Moreover, the system can control the battery balancing circuit and battery protection switch to protect the battery module charging and discharging process safety. The modular battery management system is mainly composed of a mixed-signal processor, voltage measurement, current measurement, temperature measurement, battery balancing, and protection switch module. The testing results show that the errors between the voltage value measured by the voltage measurement module and the actual value are less than 0.5%, about 1% under the conditions of different charging and discharging currents of 9 A and 18 A for the current measuring module, less than 1% for the temperature measurement module; and the battery balancing in the battery management system during the charging process. When the module is charged at 4.5 A for about 805 s, each cell of the battery has reached the balancing state. Finally, the testing results validate that the modular battery management system proposed in this paper can effectively manage the battery balancing of each cell in the battery module, battery module overcharge, over-discharge, temperature protection, and control.

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Photovoltaic power generation systems often suffer from voltage instability and intermittent production of electricity due to shade, dust, rain, and so forth, resulting in unstable power quality. Such problems of photovoltaic power generation systems cause the malfunction of devices connected to the system, especially in systems with brushless DC motors. To solve these problems, a hybrid energy storage module and a precise control strategy for photovoltaic power generation systems are proposed. The system comprises solar cells, a hybrid energy storage module, a power conversion module, a sensing-type pyrheliometer, and a brushless DC motor. The hybrid energy storage module is composed of a supercapacitor and a lithium-ion battery, which are connected in parallel. The power conversion module includes a maximum power point tracking converter, a boost converter, a controller, and switches. The sensing-type pyrheliometer monitors the luminous intensity during operation, which enables the controller to analyze the signals of the system and control the system through the terminal voltage of the hybrid energy storage module. A brushless DC motor is connected to the system to investigate by how much the power quality and operation time are improved. The experimental results show that the system has a sustainable power supply because the brushless DC motor operates for up to 342 s without any interruption, longer than that for a photovoltaic system with a supercapacitor only. Thus, the photovoltaic power generation system with the proposed hybrid energy storage module and the control strategy effectively reduces the voltage instability and the interruption of power generation and improves the quality of the power.

In view of the intermittent and unstable output voltage of the photovoltaic power generation module, a supercapacitor is designed as the control system to improve the power quality and power supply continuity of the photovoltaic power generation system. The whole circuit includes a maximum power point tracking converter, a boost converter, a Hall element, a waveform recorder, and a supercapacitor bank. Because the output current of each solar photovoltaic module is very important for the control of the solar power generation system with a supercapacitor bank, a sensing circuit for accurately detecting the output current and current change rate of the solar power generation system is presented. When the sunshine is sufficient, the control system dispatches the output current of the solar photovoltaic module and provides power to the supercapacitor bank and the load terminal; when the sky is cloudy, the control system discharges the energy stored in the supercapacitor as an uninterruptible power source and provides power to the load such that the load terminal voltage is stable. The measured results show that the control system can effectively suppress the output voltage fluctuation of the photovoltaic power generation module, improve the power quality, and enhance the reliability of load power consumption.