The present invention relates to a Robot Electronics Unit (REU) motor controller board (MCB) with a trapezoid wave design, which can utilize power efficiently and reduce electromagnetic interference. The MCB uses a modulator or Buck Converter to regulate the voltage before it is passed to the motors used in robotic arms in space applications. The REU MCB includes: a commutator disposed on the MCB and connected to a three-phase induction motor; and a modulator disposed on the MCB and which precedes the commutator, the modulator which utilizes pulse width modulation (PWM) to regulate a voltage to the commutator and provide a predetermined current to the commutator. The modulator regulates the voltage by stepping it down from a 100V power input signal before the voltage is passed to the motor. The output of the modulator includes a trapezoid waveform design which controls the motor and reduces electromagnetic interference.