[Piotrsko]

Frequency is important to most AC induction motors: freezers, fridges, fans, compressors. There's a lag angle built in for maximum efficiency. Transformer less powersupplies, maybe no effect. Being off frequency just causes power inefficiency, for fans/motors that just run faster or slower and get MUCH hotter. Some asynchronous motors rely on frequency to work. Could even crispy some electronics because they are shunting full voltage

Since most controllers use igbts for control, they also use pwm to change voltage through a LC time constant circuit. Generally called a chopper circuit back in the day. Guaranteed somewhere in the power band your EV has a 60 cycle output, dependent on pole count and rpm of the motor, even if it's DC.