Electric Drive System Inverter Motor Connection Detection
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Solution Overview
Problem
The existing electric drive systems in automotive vehicles are costly and complex due to the use of non-standardized components, such as three-wire high-voltage cables with embedded dedicated low-voltage signal cables and multiple current sensors, which increase size, cost, and create false failure modes by not directly detecting the connection between the inverter and motor.
Innovation Solution
An electric drive system that includes a voltage source inverter generating high-frequency common-mode pulse-width-modulated voltage, a current transformer for sensing high-frequency common-mode current, and a controller to determine the electrical connection between the inverter and motor using a resolver for position information and dynamic state estimation, reducing the need for multiple current sensors and non-standardized components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple current sensors are used to detect current flowing through the high-voltage cable, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the interlock detection function from the existing current sensor system. By using the existing current sensors primarily for their intended purpose (current measurement for motor control) and extracting a small portion of their signal for interlock detection, the system avoids adding dedicated detection components while maintaining measurement precision.
Solution Approach 2:
The existing current sensors are made multi-functional by using them both for motor control current measurement and for interlock system detection. The controller processes the current sensor signals to detect both motor operating conditions and cable connection status, eliminating the need for separate dedicated detection sensors.
2Reliability
If a dedicated low-voltage signal cable is embedded in the high-voltage cable for interlock detection, then reliability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts the interlock detection function from the physical cable structure and relocates it to the control software. Instead of embedding a dedicated signal cable in the high-voltage connector, the system uses the existing electrical connection and detects interlock status through software-based analysis of current sensor signals and voltage measurements.
Solution Approach 2:
The patent replaces the mechanical/electrical interlock detection system (dedicated low-voltage signal cable embedded in connectors) with an electronic/software-based detection system. The controller uses algorithms to analyze electrical parameters and determine connection status, eliminating the need for specialized mechanical cable assemblies.
3Measurement precision
If non-standardized components are used for interlock detection, then measurement precision is improved, but ease of manufacture and cost increase
Solution Approach 1:
The patent makes existing standardized components multi-functional. The standard high-voltage cable with three wires serves both its primary function (power transmission) and the interlock detection function. The controller uses the existing current sensors and voltage measurements to detect connection status, eliminating the need for non-standardized dedicated detection cables and connectors.
Solution Approach 2:
The existing electrical connection infrastructure serves itself by providing both power transmission and interlock detection capabilities. The same three-wire high-voltage cable that transmits power also enables the controller to detect connection status through intelligent analysis of electrical parameters, eliminating the need for separate dedicated detection infrastructure.
4Reliability
If the interlock system uses a dedicated circuit and embedded signal cable, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the interlock detection function with the existing motor control system. The same controller that manages motor operation also performs interlock detection by analyzing current sensor signals and voltage measurements. This consolidation eliminates dedicated interlock circuits and reduces the number of separate components while maintaining safety functionality.
Solution Approach 2:
The controller is made multi-functional by integrating both motor control and interlock detection capabilities. The existing current sensors and voltage measurement circuits are used for both motor operation control and safety interlock monitoring, eliminating the need for separate dedicated interlock detection hardware.
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 solution simplifies the electric drive system, reduces costs, and enhances reliability by accurately detecting the connection between the inverter and motor, eliminating unnecessary failure modes and the need for non-standard components, while improving efficiency and accuracy.
Implementation Method 1
generating a high-frequency common-mode pulse-width-modulated voltage
Implementation Method 2
a current transformer for sensing high-frequency common-mode current
Data Source
AI summary
An electric drive system in an automotive vehicle includes a controller for determining a condition of the electric drive system. The electric drive system includes only two current sensors and a common-mode current transformer. In response to the current sensors and the common-mode current transformer, the controller determines the condition of the electric drive system. The condition of the electric drive system may depend on a condition of an electrical connection between a drive system inverter and a motor in the electric drive system as well as a calculated amount of error in the electric drive system. In addition, the controller may control various operations of the electric drive system, which may or may not depend on the condition of the electric drive system.