Sensorless Motor Position Estimation in MDPS Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing motor control systems for motor-driven power steering (MDPS) systems rely on position sensors to detect the rotor position, which are large, complex, and fail when broken, preventing motor operation.
Innovation Solution
A motor control apparatus and method that estimates the rotor position using calculated motor position increments based on current command values, measured currents, and stored motor parameters, allowing for motor control without a position sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a position sensor is installed to detect rotor position, then motor control accuracy is improved, but device complexity and size increase
Solution Approach 1:
The patent extracts the position detection function from a separate physical sensor and implements it through calculation using existing current measurement data. The rotor position is derived by calculating the phase electrical angle from current command values and measured current values, eliminating the need for a dedicated position sensor and its associated complexity.
Solution Approach 2:
The patent uses current measurement values as an intermediary to infer rotor position. Instead of directly measuring position, the system uses current data as a mediator to calculate the phase electrical angle, which then represents the rotor position information needed for control.
2Ease of operation
If a position sensor is used to detect rotor position, then motor control is enabled, but reliability decreases when sensor fails
Solution Approach 1:
The system uses its own existing current measurement infrastructure to perform position detection, making the system self-sufficient. The same current sensors used for motor control also provide the data needed for position detection, eliminating single points of failure and reducing reliability concerns associated with additional sensors.
Solution Approach 2:
The current measurement system serves dual purposes: both motor control and position detection. By making the current measurement infrastructure multi-functional, the patent eliminates the need for separate position sensors and ensures that position information remains available even if dedicated position sensing components fail.
3Ease of operation
If a position sensor is installed to detect rotor position, then motor operation is enabled, but weight and size increase
Solution Approach 1:
The patent extracts position detection capability from separate sensing hardware and embeds it within the existing current measurement and control processing infrastructure. This eliminates the need for additional position sensor components, reducing overall system weight.
Solution Approach 2:
The control system performs multiple functions using the same hardware components. The current measurement system simultaneously provides data for both motor control and position detection, eliminating redundant components and reducing overall system weight.
Data Source
AI summary
A motor control apparatus of a motor driven power steering (MDPS) system may include: a steering logic controller configured to calculate a current command value for motor control, and transmit the current command value; a current measurement sensor configured to measure a current applied to the motor; and a controller configured to calculate a motor position increment based on the current command value received from the steering logic controller, the measured current value received from the current measurement sensor, and previously stored motor parameters, estimate a current motor position by integrating the calculated motor position increments, and control the motor using the estimated current motor position.