Sensorless PMSM Angle Estimation Using Clarke Park Transforms
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Solution Overview
Problem
Existing sensor-less control systems for permanent magnet synchronous motors (PMSMs) require expensive and high-speed digital signal processing due to complex calculations, making them costly and unreliable, and there is a need for a low-cost alternative that can effectively estimate the angle without sensors.
Innovation Solution
A method and control system using a low-cost general microcontroller that includes a Clarke transform module, a Park transform module, and an angle estimation module to generate orthogonal current signals and commutation angle signals, allowing for sensor-less field-oriented control (FOC) by controlling the current signal to be approximately zero and generating three-phase motor voltage signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensor-less control systems use complex calculations with expensive DSPs, then angle estimation precision is improved, but system cost and complexity increase
Solution Approach 1:
The patent replaces expensive DSPs with low-cost microcontrollers that have sufficient processing capability for the simplified algorithm. The approach uses affordable hardware resources to achieve the required angle estimation precision without relying on high-end processors.
Solution Approach 2:
The patent extracts and removes the complex computational requirements from the control system by simplifying the angle estimation algorithm. The simplified algorithm eliminates the need for complex matrix operations and high-speed processing, retaining only the essential calculations needed for accurate angle estimation.
2Measurement precision
If hall-sensor devices are used to sense rotor position, then measurement precision is improved, but system cost and reliability are worsened
Solution Approach 1:
The motor system estimates its own rotor position using electrical measurements (currents and voltages) and a simplified algorithm, eliminating the need for external hall sensors. This self-service approach improves reliability by removing additional sensing components while maintaining sufficient measurement precision for control purposes.
3Measurement precision
If complex angle estimation algorithms are implemented, then angle estimation precision is improved, but processing speed requirements and cost increase
Solution Approach 1:
The patent extracts the essential angle estimation function from complex computational algorithms, retaining only the necessary calculations based on current and voltage measurements. This simplified approach achieves sufficient precision without requiring high-speed processing capabilities.
Solution Approach 2:
The patent changes the computational parameters and algorithm structure to reduce processing complexity. By modifying the estimation approach to use simpler mathematical operations and fewer computational steps, the system achieves acceptable precision with standard microcontroller processing speeds.
Data Source
AI summary
An angle estimation control system of a permanent magnet motor is provided. The angle estimation control system includes a Clarke transform module, a Park transform module, and an angle estimation module. The Clarke transform module generates orthogonal current signals in accordance with motor phase currents. The Park transform module generates a current signal in response to the orthogonal current signals and an angle signal. The angle estimation module generates the angle signal in response to the current signal. The angle signal is related to a commutation angle of the permanent magnet motor. The current signal is controlled to be approximately equal to zero. The angle signal is further coupled to generate three phase motor voltage signals.