Belt Slip Detection Using Electric Machine Electrical Parameters
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Solution Overview
Problem
Current methods for detecting belt slip between an electric machine and an internal combustion engine using a drive belt are inefficient, requiring expensive data bus systems and lacking accuracy at low engine speeds, especially with missing tooth speed sensors.
Innovation Solution
A method that determines belt slip by analyzing the rotational speed, current, and voltage of the electric machine, allowing for precise detection without external sensors or high-speed data buses, and reduces torque when slip is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a missing tooth speed sensor is used to detect belt slip, then the detection system is simple, but the accuracy is insufficient at low engine speeds
Solution Approach 1:
The patent replaces the mechanical missing tooth speed sensor with an electrical parameter-based detection method. By monitoring current, voltage, and rotational speed of the electric machine, the system detects belt slip conditions without requiring additional mechanical sensors, thereby maintaining simplicity while improving accuracy across all engine speeds including low-speed operation.
Solution Approach 2:
The patent changes the detection parameters from mechanical speed signals to electrical parameters (current, voltage, and rotational speed). This parameter transformation enables accurate belt slip detection at low engine speeds where traditional speed sensors fail, while keeping the detection system simple by utilizing existing electrical measurements.
2Measurement precision
If a high repetition frequency data stream is transmitted over a data bus, then the speed measurement is accurate, but the data bus system becomes expensive
Solution Approach 1:
The patent extracts the belt slip detection function from the high-frequency data bus system. By calculating belt slip conditions locally using current, voltage, and rotational speed measurements, the system eliminates the need for expensive high-repetition-frequency data bus transmission while maintaining accurate speed measurement and detection capabilities.
Solution Approach 2:
The patent replaces the expensive data bus system with a simpler, more cost-effective approach using existing electrical parameters. The solution uses readily available current, voltage, and speed data that are already measured by the electric machine control system, eliminating the need for additional expensive communication infrastructure.
3Measurement precision
If the number of teeth on the speed sensor is increased to improve accuracy, then the speed signal precision improves, but the data stream size increases requiring more processing power
Solution Approach 1:
The patent replaces the mechanical approach of increasing sensor teeth with an electrical parameter-based calculation method. By using current, voltage, and rotational speed measurements to detect belt slip, the system achieves high accuracy without generating large data streams, thereby maintaining high data processing efficiency while improving measurement precision.
4Reliability
If torque is reduced when belt slip is detected, then the belt is protected from damage, but the driving performance decreases
Solution Approach 1:
The patent applies preliminary anti-action by detecting belt slip conditions and preemptively reducing torque to prevent belt damage. The system monitors electrical parameters to identify slip conditions early and reduces motor torque before excessive belt wear or failure occurs, protecting the belt while minimizing impact on driving performance through controlled torque reduction.
Data Source
AI summary
A method and apparatus is disclosed for detecting whether belt slip is occurring between an electric machine and a machine drivingly connected together by a drive belt using only measurements of rotor speed, voltage and current derived from the electric machine, thereby improving the sensitivity of slip detection and eliminating the need for a comparison of rotor speed with a measurement of the rotational speed of the machine.