| 摘要 |
PROBLEM TO BE SOLVED: To ensure protection of a motor and a motor drive, by calculating a value on the temperature of a motor coil or a motor drive driver stage based on motor coil current, voltage and inductive voltage, and limiting or inhibiting motor driving if it exceeds any of their temperature allowances. SOLUTION: A CPU16 determines a coil current value Ic from current measuring voltage V1 , stores it in a RAM18, and compares with preset maximum current ILMT. If an absolute current value|Ic|exceeds the maximum current ILMT, the CPU turns off an output inhibiting switch 4 through an output port 14, determines a coil resistance value Rc=(Vc -VA)/Ic from motor speed v=(p(t)-p(t-1))/Δt(p(t):p(t-1) stored present position, where p(t-1): last stored position andΔt: storage cycle) and inductive voltage VA=k.v (k: thrust constant) and compares it with the maximum current ILMT. If a coil resistance value Rc exceeds a maximum resistance value RLMT, the CPU turns off the output inhibiting switch 4. |
