Integrated Starter-Generator Rotor Position Detection via PWM Current
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Solution Overview
Problem
Conventional Integrated Starter Generator (ISG) systems face issues with sensor reliability and cost due to harsh operating conditions, such as high temperatures and vibrations, which lead to sensor failure and require additional space and wiring for signal transmission, impairing system operation.
Innovation Solution
A method and system for controlling an integrated starter-generator using a control unit that determines the initial and updated rotor position through pulse-width-modulated signals and current measurement, eliminating the need for hall-effect sensors by utilizing an ignition trigger sensor to monitor rotor speed and position, thereby simplifying the system and reducing the risk of sensor failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hall-effect sensors are placed inside engine casing to sense rotor position, then rotor position detection is achieved, but sensor reliability deteriorates due to harsh operating conditions such as high temperature and vibrations
Solution Approach 1:
The patent extracts the rotor position detection function from the harsh engine interior environment by using the ignition trigger sensor located in the ignition system. Instead of placing sensors inside the engine casing where temperature and vibrations cause failure, the system utilizes the existing ignition trigger sensor that operates in a more favorable environment while still providing rotor position information through the ignition timing signal.
Solution Approach 2:
The ignition trigger sensor, originally designed for ignition timing purposes, is repurposed to also provide rotor position detection functionality. This multi-functional approach eliminates the need for dedicated rotor position sensors in the harsh engine environment, as the ignition trigger sensor serves dual purposes: ignition control and rotor position sensing.
2Measurement precision
If hall-effect sensors and magnetic rings are placed inside engine casing, then rotor position sensing is enabled, but device complexity increases due to special mounting arrangements and wiring requirements
Solution Approach 1:
The patent removes the complex sensor mounting arrangements and wiring by extracting the position sensing function to the ignition trigger sensor. This eliminates the need for separate magnetic rings, sensor housings, and wire routing through the engine casing, as the ignition trigger sensor is already integrated into the ignition system with existing connections to the ECU.
Solution Approach 2:
The ignition trigger sensor performs multiple functions: ignition timing control and rotor position detection. This eliminates the need for separate dedicated position sensing components and their associated mounting hardware and wiring, thereby reducing overall device complexity.
3Measurement precision
If multiple sensors and wiring are used for rotor position detection, then measurement accuracy is improved, but loss of time increases due to wire routing and connection requirements
Solution Approach 1:
The patent eliminates wire routing time by extracting the position sensing function to the ignition trigger sensor, which is already electrically connected to the ECU through the ignition system wiring. No additional wire routing or connection time is required compared to the existing ignition system installation.
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
This approach enhances the reliability and efficiency of the ISG system by reducing the complexity and cost associated with sensor placement and wiring, while maintaining accurate rotor position determination and excitation, thus improving overall system performance.
Implementation Method 1
The integrated starter-generator comprises a rotor having a plurality of permanent magnet poles and a stator having a plurality of phase windings disposed on the stator... applying a pulse-width-modulated signal to the stator winding corresponding to determined initial position of the rotor
Implementation Method 2
determining an initial position of the rotor with respect to a stator phase winding... monitoring a trigger signal from an ignition trigger sensor coupled to the engine
Data Source
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Figure 3
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AI summary
The present invention relates to a method for controlling an integrated starter-generator. The method comprising the steps of: receiving a start signal; determining an initial position of a rotor with respect to a stator phase winding integrated starter- generator of the integrated starter- generator; applying a pulse-width-modulated signal to the stator winding corresponding to determined initial position of the rotor; measuring current of the stator winding in response to applied pulse-width-modulated signal to determine current variation; if current variation is more than a threshold value, determining updated rotor position and applying a pulse-width-modulated signal to the stator winding corresponding to the updated rotor position; determining speed of the rotor, if speed of the rotor is more than a threshold value, monitoring a trigger signal from an ignition trigger sensor coupled to the engine; and if the trigger signal is received, determining the updated rotor position and exciting the stator winding corresponding to the updated rotor position.