Power Module Temperature Estimation from Switch Loss in Motor Drives
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Solution Overview
Problem
Existing motor drive technologies face challenges in optimizing power conversion efficiency and torque generation, leading to reduced fuel efficiency and limited acceleration performance due to increased windings and voltage utilization rate disparities, necessitating a solution that can manage both low- and high-power intervals effectively.
Innovation Solution
A motor driving apparatus with dual inverters and changeover switches, utilizing a controller to determine power losses and temperature of power modules based on driving modes and operation states without separate temperature sensors, enabling precise temperature estimation and current control to protect switch elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the number of windings is increased to enhance maximum torque, then the maximum torque is improved, but the voltage utilization rate section moves away from the low torque region, resulting in poor fuel efficiency
Solution Approach 1:
The system dynamically switches between two inverter configurations (first inverter with Y-connection for low torque, second inverter with W-connection for high torque) based on the motor's operating conditions. This dynamic adaptation allows the system to operate at high voltage utilization rate in low torque region for fuel efficiency, while providing high maximum torque when needed, resolving the contradiction between torque enhancement and fuel efficiency.
2Device complexity
If a single inverter is used to drive the motor, then the device complexity is reduced, but the system cannot effectively cover both low- and high-power intervals, limiting productivity
Solution Approach 1:
The power conversion system is segmented into two separate inverters with different connection configurations. The first inverter uses Y-connection optimized for low torque region operation, while the second inverter uses W-connection optimized for high torque region operation. This segmentation allows each inverter to be specialized for its operating range, improving overall power conversion efficiency and enabling effective coverage of both low- and high-power intervals.
3Measurement precision
If separate temperature sensors are used for each switch element, then the measurement precision is improved, but the device complexity and cost increase
Solution Approach 1:
The system uses itself to measure temperature by calculating power loss in each switch element based on operating conditions (current, voltage, switching state) and using this power loss information to estimate temperature. This self-service approach eliminates the need for separate temperature sensors while providing accurate temperature estimation for thermal management and protection of switch elements.
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
Improves temperature estimation accuracy and protects switch elements by controlling current based on determined temperature, enhancing system efficiency and preventing component failure.
Implementation Method 1
determine a power loss of each of the top switch, the bottom switch, and the changeover switch based on the motor driving mode and an operation state of the motor to obtain a total power loss of the at least one power module, and determine a temperature of the at least one power module based on the total power loss
Data Source
AI summary
A motor driving apparatus includes: a driving unit which is implemented as at least one power module and includes a top switch, a bottom switch, and a changeover switch configured to switch a motor driving mode; and a controller configured to determine a power loss of each of the top switch, the bottom switch, and the changeover switch to obtain a total power loss of the at least one power module, and determine a temperature of the at least one power module based on the total power loss.