Pre-driver Circuit for Electric Work Vehicle Parking Brake Safety

The patent introduces a pre-driver circuit as an intermediary component between the controller and the inverter. This pre-driver circuit receives the parking brake condition signal independently and can cut off the gate signal to the inverter directly, without relying on the controller's PWM output. This intermediary structure ensures that even if the controller malfunctions, the pre-driver circuit can still execute the power transmission cutoff function, thereby resolving the contradiction between simplified control system and reliable power cutoff.

The patent segments the control function into two independent parts: the controller handles normal motor drive control, while the pre-driver circuit handles the safety function of cutting off power transmission when the parking brake is activated. This segmentation allows the pre-driver circuit to operate independently with a simple logic circuit that monitors the parking brake condition and can cut off the gate signal directly, eliminating the need for redundant controllers while maintaining high reliability.

The patent replaces the traditional mechanical/electrical relay-based power cutoff mechanism with an electronic gate signal cutoff mechanism. The pre-driver circuit uses electronic logic to detect the parking brake condition and directly controls the gate signals to the inverter's switching elements. This electronic substitution achieves reliable power transmission cutoff with simpler circuitry compared to traditional mechanical relay systems, as the gate signal cutoff is achieved through logical operations rather than physical switching mechanisms.