AC Motor Gear Control Circuit for Sequential Switching

The patent applies preliminary action by sequentially turning on intermediate gears before the target gear. When switching from gear n to gear m (where m > n), the controller first activates switches for gears n+1, n+2, ..., m-1 in sequence, and only then turns on the switch for gear m. This gradual transition prevents sudden inrush current by preparing the circuit path in advance, reducing energy losses and extending switch service life while maintaining acceptable switching speed.

The patent applies segmentation by dividing the gear switching process into multiple sequential steps rather than a single abrupt transition. When switching from gear n to gear m, the controller segments the operation into: (1) sequentially turning on switches for intermediate gears n+1 through m-1, and (2) finally turning on the switch for gear m. This segmentation transforms one large inrush current event into multiple smaller, controlled current transitions, maintaining productivity while protecting switch reliability.

The patent applies the intermediary principle by introducing a controllable switch (such as a triode or MOSFET) as a mediator between the PWM signal and the high-power electronic device. The PWM signal controls the switching of this intermediate component, which in turn controls the power flow to the high-power device. This intermediary approach allows the low-power PWM signal to effectively control high-power devices while maintaining energy efficiency, overcoming the limitation of direct PWM control.