Sensorless Motor Control via Magnetic Pole Discrimination
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Solution Overview
Problem
In eco-friendly vehicles, motor control systems relying on rotor position sensors can fail due to wiring issues or short circuits, leading to unsafe driving conditions when the sensor's position information is distorted, causing unintended driving forces and requiring the inverter to stop motor current control, thus compromising driver safety.
Innovation Solution
An apparatus that estimates the rotor position using a sensorless algorithm, comprising a current controller, signal generator, inverter, and processor, which generates a magnetic pole discrimination reference signal and determines the rotor's polarity based on response components from the driving current, allowing motor control without a position sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rotor position sensor is used to control motor current, then motor control precision is improved, but system reliability deteriorates due to wiring issues and sensor failures
Solution Approach 1:
The patent extracts and eliminates the rotor position sensor from the motor control system. Instead of using a physical sensor to detect rotor position, the system uses sensorless control algorithms that estimate rotor position based on motor current and voltage measurements. This removes the wiring connections and sensor components that cause reliability issues while maintaining the necessary position information for control.
Solution Approach 2:
The patent replaces the mechanical/electrical sensor system with an electronic estimation system. Rather than physically measuring rotor position with a sensor, the system uses mathematical models and signal processing to estimate position based on electrical measurements (current and voltage), substituting a reliable electronic computation approach for the fragile physical sensing approach.
2Measurement precision
If error logic stops inverter current control when sensor problems are detected, then measurement precision is maintained, but vehicle safety deteriorates due to loss of motor control
Solution Approach 1:
The patent implements preliminary action by proactively eliminating the sensor that could fail before any failure occurs. The sensorless control system is designed from the beginning without a physical rotor position sensor, so there are no sensor wiring issues or sensor failures to trigger error conditions. The system continuously estimates rotor position through calculation rather than measurement, preventing the need to stop control due to sensor problems.
Solution Approach 2:
The patent ensures continuity of useful action by maintaining motor control capability at all times through sensorless estimation. Since there is no physical sensor that can fail, the control system continues to operate continuously without interruption. The rotor position is continuously estimated based on ongoing current and voltage measurements, ensuring uninterrupted motor control and maintaining vehicle safety.
3Measurement precision
If a rotor position sensor is installed in the motor, then rotor position detection is improved, but device complexity increases due to additional wiring and connectors
Solution Approach 1:
The patent extracts and removes the rotor position sensor and its associated wiring from the motor system. The sensorless control approach eliminates the need for external signal wiring between the motor and control unit for position feedback. Only basic current sensing remains, which is already necessary for motor control, thereby reducing wiring complexity and the number of connectors.
Solution Approach 2:
The patent applies universality by using the existing current sensors and voltage measurements (already present for motor control) to serve dual purposes: both motor control and rotor position estimation. This eliminates the need for separate position sensing wiring, as the same electrical measurements used for control also provide position information through computational estimation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables safe and accurate motor control by determining the rotor's position and magnetic pole in a wider range, preventing unsafe driving conditions and ensuring continuous vehicle operation even when sensor issues arise.
Implementation Method 1
a processor including a control logic deriving a response component to the magnetic pole discrimination reference signal from a driving current transferred to the motor from the inverter, the processor determining a polarity of a rotor of the motor based on the response component
Data Source
AI summary
An apparatus for controlling a motor of a vehicle includes: a current controller generating a voltage instruction for driving the motor; a signal generator generating a magnetic pole discrimination reference signal that is combined with the voltage instruction; an inverter driving the motor on the basis of a corrected voltage instruction obtained by comparing the voltage instruction and the magnetic pole discrimination reference signal; and a processor including a control logic for deriving a response component to the magnetic pole discrimination reference signal from a driving current transferred to the motor from the inverter, and for determining a polarity of the rotor of the motor on the basis of the response component.