Controllers for controlling hybrid motor drive circuits configured to drive a motor are provided herein. A controller is configured to drive the motor using an inverter when a motor commanded frequency is not within a predetermined range of line input power frequencies, and couple line input power to an output of the inverter using a first switch device when the motor commanded frequency is within the predetermined range of line input power frequencies.

An induction-type AC electric motor system has a variable frequency motor (VFD) drive having at least two outputs, the VFD drive coupled to be powered by a solar input and to power the motor with a switching device in a first setting. With the switching device in a second setting, a run winding of the AC electric motor couples to an AC input and a start winding of the AC motor couples through a capacitor and start switch to the AC input. The system is configured to, upon determining motor start, put the contactor in first setting and use the VFD drive to continue running the motor, and, when the AC motor is not rotating, the system is configured to periodically measure available solar power and to start the AC motor if the available solar power exceeds a first threshold power determined sufficient to run the AC motor.

Controllers for controlling hybrid motor drive circuits configured to drive a motor are provided herein. A controller is configured to drive the motor using an inverter when a motor commanded frequency is not within a predetermined range of line input power frequencies, and couple line input power to an output of the inverter using a first switch device when the motor commanded frequency is within the predetermined range of line input power frequencies.

Disclosed herein are a method for controlling a medium-voltage inverter, and a system including the same. The system includes a motor, a medium-voltage inverter driving the motor, a control unit configured to control an output voltage from the medium-voltage inverter, and an output voltage measuring unit configured to measure counter electromotive force data of the motor including a voltage and a frequency of the counter electromotive force, and transmitting it to the control unit. The control unit generates the output voltage based on the measured counter electromotive force data to re-drive the motor when the output voltage measuring unit completes the measurement of the counter electromotive force data.

The invention relates to a control apparatus for a refrigerator compressor having at least one two-phase AC asynchronous motor (K1, K2), having mains connection means (10) for connection to a preferably public voltage supply network Which nominally provides a mains AC voltage of between 85 V and 264 V, in particular between 100 V and 230 V, first voltage converter means (14) which are connected downstream of the mains connection means and are intended to generate an intermediate voltage, in particular an intermediate DC voltage, from the mains AC voltage, second voltage converter means (16-1, 16-2) which are connected downstream of the first voltage converter means and are intended to generate an output signal which is independent of a level and a mains frequency of the mains AC voltage, in particular has a constant voltage and/or frequency in periods, and is intended to control the refrigerator compressor with an AC voltage of a plurality of differently predefinable voltage levels, wherein the mains connection means are assigned voltage detector means (12) for capturing the mains AC voltage, the detector output signal from which can be evaluated by the second voltage converter means or control means (24) assigned to the latter for the purpose of generating a mains-voltage-dependent maximum value for a current of the output signal.

A compressor unit (2) for use in a refrigeration circuit, comprises at least two compressors (8, 10); and a common variable frequency drive (6), configured to be connected to a three phase grid voltage supply (4); each compressor (8, 10) having an inlet port (12) configured to be in refrigerant communication, via a suction line, with an outlet of an evaporator; an outlet port (14) configured to be in refrigerant communication, via a pressure line, to an inlet of a condenser; a compressor motor (18), particularly an alternating current induction motor, with a three phase supply line (32-1, 32-2); a power modulation means (24) for controlling the power of the compressor (8, 10) according to its load needs; wherein each compressor (8, 10) is switchable, independently from the respective other compressor(s) (8, 10), to be connected, during start-up and acceleration of the respective compressor (8, 10), to the common variable frequency drive (6), and to be connected, during rated-speed operation of the respective compressor (8, 10), to a common three phase grid voltage supply (4).

Controllers for controlling hybrid motor drive circuits configured to drive a motor are provided herein. A controller is configured to drive the motor using an inverter when a motor commanded frequency is not within a predetermined range of line input power frequencies, and couple line input power to an output of the inverter using a first switch device when the motor commanded frequency is within the predetermined range of line input power frequencies.

Disclosed herein are a method for controlling a medium-voltage inverter, and a system including the same. The system includes a motor, a medium-voltage inverter driving the motor, a control unit configured to control an output voltage from the medium-voltage inverter, and an output voltage measuring unit configured to measure counter electromotive force data of the motor including a voltage and a frequency of the counter electromotive force, and transmitting it to the control unit. The control unit generates the output voltage based on the measured counter electromotive force data to re-drive the motor when the output voltage measuring unit completes the measurement of the counter electromotive force data.

A system for reducing inrush loading when a source power is restored includes a device for switching power that selectively connects a load to the source of power and a circuit for measuring the AC voltage at the source and for determining when the AC voltage is within operating range. Responsive to the AC voltage being within operating range, the system delays for a time period then connects the load to the source of power by way of the device for switching power.

Solar Motor Controller is an electronic device with DC power input terminals that may connect directly to solar PV panels, and output terminals that may connect directly to single or multiphase phase AC electric motors without requiring an energy storage subsystem. The Controller runs electric motors of many frequencies and is capable of interfacing to multiple voltages of solar PV panels with or without maximum power point tracking. The Controller may drive motors in water pumping, HVAC, refrigeration, compressors operation, blowers, machine tools, and many other applications; some controller applications may operate at motor speeds adjusted to conform to power available from attached solar panels.