Multi-Motor Inverter Control for Sensorless Speed Shift Stabilization
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Solution Overview
Problem
Existing technologies lack an effective solution for operating multiple sensorlessly controlled PMSM/EC motors on a single inverter, as they require complex current detection and multiple observers, leading to inefficiencies and pendulum movements between motors.
Innovation Solution
The implementation of an additional current detection device to measure phase currents for each motor, allowing for the detection of rotor position shifts and system oscillations, which are then regulated by a stabilization controller using the dq transformation and rotor-position-dependent current sampling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple sensorlessly controlled motors are operated on a single inverter using conventional methods, then the system can run multiple motors, but complex current detection and multiple observers are required leading to high device complexity and pendulum movements between motors
Solution Approach 1:
The patent combines multiple motor phase current measurements into a single residual current measurement at the inverter output. Instead of requiring separate current detectors for each motor phase, the system measures the sum of all motor phase currents (residual current) and uses this single measurement to control all motors, significantly reducing device complexity while maintaining the ability to operate multiple motors
Solution Approach 2:
The residual current measurement serves multiple functions simultaneously: it provides speed information for all motors, enables sensorless rotor position detection, and facilitates stable parallel operation of multiple motors. This multi-functional approach eliminates the need for separate observation systems for each motor
2Measurement precision
If separate current acquisition is carried out for each motor connected to the multi-motor inverter, then individual motor control is achieved, but the number of current sensors and computing power requirements increase
Solution Approach 1:
The patent extracts the essential control information from individual motor phase currents by computing their sum (residual current). Instead of measuring each motor's phase currents separately with dedicated sensors, the system extracts the combined current information at the inverter output, which contains sufficient data to control all motors without requiring individual sensor measurements for each motor
Data Source
AI summary
The invention relates to a control system (1) comprising a multi-motor inverter (PWR) for the controlled parallel operation of a number of n EC motors (M1, . . . , Mn) whose respective rotor position is detected sensorlessly and controlled by the common inverter.