Abstract: A method and apparatus are implemented in software to control motor speed as a function of available power in a DC source—inverter—AC motor system, i.e. to perform maximum power tracking of motor speed. An inverter or motor drive converts DC power from a DC source, such as a solar panel, to AC power, to power the motor. The inverter or motor drive is controlled by software, implemented either by programmable features built directly into the inverter or drive or by a separate programmable device connected to the inverter or drive, to track motor power as a function of source power. The software-controlled inverter or drive sets motor speed as a function of source power by sensing only a single parameter, the DC source voltage. The software-controlled inverter or drive samples the source voltage at preset intervals, and changes the frequency of the AC output of the inverter or drive to match or track the available power so that the motor operates at or near its optimum for any source voltage.

Abstract: A method and apparatus are implemented in software to control motor speed as a function of available power in a DC source-inverter-AC motor system, i.e. to perform maximum power tracking of motor speed. An inverter or motor drive converts DC power from a DC source, such as a solar panel, to AC power, to power the motor. The inverter or motor drive is controlled by software, implemented either by programmable features built directly into the inverter or drive or by a separate programmable device connected to the inverter or drive, to track motor power as a function of source power. The software-controlled inverter or drive sets motor speed as a function of source power by sensing only a single parameter, the DC source voltage. The software-controlled inverter or drive samples the source voltage at preset intervals, and changes the frequency of the AC output of the inverter or drive to match or track the available power so that the motor operates at or near its optimum for any source voltage.

Abstract: A motor is shut off when its operation encounters no load conditions, e.g. low water conditions for a submersible pump motor. The shutoff signal is obtained from the motor frequency and motor power. When motor frequency exceeds the rated frequency and motor power drops to a preselected level below rated power, a shutoff signal is produced. The motor can be kept off for a preselected period of time before attempting to restart.