| 摘要 |
PURPOSE:To enable to calculate the average value of a motor current via one A/D conversion by correcting the current value of conducting or non-conducting points of a chopper with a power source voltage value, chopper conducting time and operating period, thereby calculating the average value of the motor current. CONSTITUTION:When an interrupt signal iRQ synchronized with the operating period of a chopper CH is generated from a timer TM, a microprocessor MPU applies a phase shift output to a programmable timer PTM. A motor iM is converted from analog to digital simultaneously upon the production of the signal iRQ, thereby obtaining the minimum value (IM)L of the iM. Thus, the average value (IM)m=(IM)L+1/2ES/LM.alpha(1-alpha/TCH) of the motor current is calculated, where ES represents power source voltage, LM represents motor circuit inductance, alpha represents chopper conducting time, TCH represents chopper operating period, and the phase shift output outputted next in response to the deviation with the command value Ip is calculated. |
