Parallel Synchronous Motor Drive Control for Power Balance
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Solution Overview
Problem
Existing systems for controlling multiple synchronous motors in parallel often result in voltage mismatch and excessive current draw due to lack of signal feedback, potentially leading to system damage.
Innovation Solution
A system and method utilizing a single motor drive with a current sensor to detect output signals and control multiple synchronous motors in parallel, incorporating vector control and scalar Volts per Hertz control with stabilization loops to maintain net active and reactive power equilibrium and reject power perturbations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single motor drive controls multiple synchronous motors in parallel without individual current sensor signals, then device complexity is reduced, but voltage mismatch occurs and motors draw excessive current
Solution Approach 1:
The patent combines multiple synchronous motors into a single parallel-controlled system using one motor drive unit, eliminating the need for separate drives for each motor. This merging approach reduces device complexity while maintaining system reliability through collective control and monitoring of all motors through a shared current sensor.
Solution Approach 2:
The patent implements a feedback mechanism where a current sensor monitors the total current drawn by all parallel-connected motors and relays this information back to the motor drive. This feedback loop enables the drive to detect voltage mismatches and adjust its output to prevent excessive current draw, thereby maintaining system reliability without requiring individual sensors on each motor.
2Reliability
If a single motor drive controls multiple synchronous motors in parallel with current sensor feedback, then system reliability is improved, but device complexity increases
Solution Approach 1:
The patent makes the single current sensor serve multiple functions by using it to monitor the collective current of all parallel motors. This universal sensing approach provides the necessary feedback for reliability while avoiding the complexity of installing and managing multiple individual sensors, thus improving reliability without proportionally increasing device complexity.
3Manufacturing precision
If vector control is used to control multiple synchronous motors in parallel, then manufacturing precision of motor operation is improved, but device complexity increases
Solution Approach 1:
The patent applies vector control algorithms to a single motor drive that controls multiple motors in parallel. By merging the control of multiple motors into one drive unit with unified vector control, the system achieves precise control of all motors simultaneously without the complexity of implementing separate vector control systems for each motor.
Data Source
AI summary
A system for controlling plurality of synchronous motors connected in parallel including a motor drive, current sensor, and plurality of synchronous motors connected in parallel to the motor drive. The synchronous motors connected to the motor drive can include the same size and power rating to allow synchronous operation and have similar load capacity. Further, the system can operate with substantially similar loads on each of the plurality of synchronous motors. The motor drive can be a variable speed drive using vector control and a closed loop current controller to control the motors. The motor drive can be a variable frequency drive using scalar control and open loop controller to control the motors. The motor drive controls the plurality of synchronous motors by maintaining net active power and net active power, and by rejecting power perturbations, at the common node.