A PLD-controlled multi-speed drive circuit for small electric vehicles

The core of control circuits for electric motors based on the pulse width modulation (PWM) principle can be realized using discrete analog or digital logic devices, microprocessors or dedicated mixed signal circuits. This paper describes a method based on a programmable logic device (PLD). The PLD follows a state machine concept and controls the bi-directional flow of energy between the source (e.g. batteries) and the motor. The complete circuit-control and power section-is currently used to supervise the drive and brake mode of small electric vehicles (bicycles, wheelchairs, carts).