Patent ID: 7456600

Claim:
A motor drive system utilizing pulse code width modulation (PCWM) technology which can drive a three phase AC motor sinusoidally, comprising: (1) an AC to DC converter which supplies a DC bus voltage to a gate drive and power transistor circuitry; (2) a unit sine function table comprising a maximum amplitude sine function to provide a unit sine function numeric n u to a PCWM signal encoder upon receipt of a table address from said PCWM signal encoder; (3) a frequency to voltage (V/F) function table to output a machine voltage v m to said PCWM signal encoder after receiving a machine frequency f m from said PCWM signal encoder; (4) said PCWM signal encoder comprising a finite state machine to update said machine frequency f m and said machine voltage v m based on an acceleration-deceleration constant k ad and a command frequency f c , and to provide PCWM numerics d to said PCWM signal decoder based on said unit sine function numeric n u using a frequency multiplication factor k fmf ; (5) said PCWM signal decoder comprising a serially connected D flip-flop, a 7-bit up-counter, and a toggle flip-flop to output center modulation pulse width modulation (PWM) signals g to said gate drive and power transistor circuitry based on said PCWM numerics d input from said PCWM signal encoder; and (6) said gate drive and power transistor circuitry to modulate said DC bus voltage corresponding to said center modulation PWM signals g output from said PCWM signal decoder, wherein said modulated DC bus voltage is for driving a three phase AC motor.