Parallel synchronous machines with single motor drive

A method of operating a system, the system comprising a single motor drive, a plurality of synchronous motors connected in parallel to the single motor drive, and a sensor to detect an output signal of the single motor drive, the method comprising:

• receiving, by the single motor drive, an input signal based on a user input,
• determining, by the single motor drive, the output signal based on the input signal;
• receiving, by the single motor drive, a feedback of the output signal from the sensor,
• wherein only one sensor detects the output signal;
• determining, by the single motor drive, a power perturbation by the plurality of synchronous motors based on the feedback from the sensor;
• and
• controlling, by the single motor drive, an operation of the plurality of synchronous motors based on the input signal and an output current;
• wherein the sensor detects the power perturbation from the plurality of synchronous motors in the output signal and the single motor drive rejects the power perturbation to maintain the plurality of synchronous motors in synchronous operation.

An apparatus for controlling multiple synchronous motors, comprising:

• a single motor drive comprising:
• an input,
• wherein the input comprises an input signal based on a user input,
• an output,
• wherein the output comprises an output signal, and
• an inverter,
• wherein the inverter converts a DC voltage to a three-phase AC output;
• at least two current sensors external to the single motor drive for detecting current on an associated two phases of the three-phase AC output at a common node, the common node comprising a node for each respective phase of the three-phase AC output,
• wherein only the at least two current sensors detect the output signal on the associated two phases of the three-phase AC output and provides a feedback to the single motor drive;
• and
• a plurality of synchronous motors,
• wherein the plurality of synchronous motors comprises being connected to the single motor drive in a parallel configuration;
• wherein the single motor drive controls an operation of the plurality of synchronous motors by controlling the output signal based on the input signal and an output current;
• and
• wherein the at least two current sensors detect a power perturbation from the plurality of synchronous motors in the output signal and the single motor drive rejects the power perturbation to maintain the plurality of synchronous motors in synchronous operation.