Output voltage control for a DC servo amplifier

摘要

In a system having a plurality of electric motors which are rated at different voltages, a voltage control circuit enables the electric motors to be connected to a common power supply. The voltage control circuit determines a first voltage appearing between the positive bus of the power supply and the motor and a second voltage appearing between the negative bus and the motor. One voltage is inverted and then summed with the non-inverted voltage to provide an average voltage. The average voltage is compared to a reference voltage and when the average voltage exceeds the reference voltage, a limit signal is generated. The limit signal is used to prevent higher voltages from being applied across the motor.