Patent ID: 8226374

Claim:
A motor drive for an electric motor of a variable fluid circulating system comprising: a user interface configured to enable selection of a signal profile from a plurality of signal profiles; a processing module that receives a signal profile selected with the user interface and generates a control signal based on the selected signal profile; and a power module that modulates a carrier signal of a power signal based on the control signal and a direct current (DC) voltage to generate a first motor drive output signal in the electric motor that matches a first selected signal profile during a first time period and to generate a second motor drive output signal during a second time period to match another signal profile selected with the user interface; and a pump connected to an output shaft of the electric motor, the pump being driven by the electric motor with reference to the first motor drive output signal during the first time period and with reference to the second motor drive output signal during the second time period to adjust injection of a fluid by the pump into a reservoir.