Precharge Resistor Circuit for Parallel Battery Inrush Control

The patent applies preliminary action by pre-charging the smoothing capacitor before connecting power storage devices in parallel. The processing circuit detects voltage differences and activates the precharge function, which charges the capacitor through a precharge resistor before parallel connection, thereby preventing inrush currents and overcurrents during system start-up while maintaining the power capacity benefits of parallel configuration

The patent uses the smoothing capacitor as an intermediary element between power storage devices with different voltages. By charging this intermediary capacitor first through a precharge resistor, the system creates a buffer that prevents direct high-current flow between devices with voltage differences, thus resolving the contradiction between parallel connection benefits and harmful current effects

The patent applies universality by making the precharge resistor serve multiple functions: it acts as a precharge resistor during system start-up to charge the smoothing capacitor, and simultaneously functions as a discharge resistor to discharge accumulated electric charges from both the smoothing capacitor and power storage devices. This eliminates the need for separate discharge resistors, reducing device complexity while maintaining reliable overcurrent prevention

The patent implements self-service by enabling the precharge resistor to discharge its own accumulated electric charges as well as charges from other circuit components. The processing circuit controls the precharge resistor to discharge charges from both the smoothing capacitor and power storage devices, making the system self-managing without requiring additional dedicated discharge components