Motor Inverter Hill Hold Control for Power Module Overheating
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Solution Overview
Problem
In electrified vehicles, the inverter's hill hold state causes unbalanced current flow, leading to overheating and potential damage in specific power modules due to excessive direct current.
Innovation Solution
A control apparatus and method for the inverter that generates a current command based on torque and temperature, compensating for overheated switching elements by reducing current input and balancing temperatures across phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hill hold control is engaged with continuous direct current output, then the motor can remain stationary on an incline, but concentrated overheating occurs in specific power modules
Solution Approach 1:
The patent implements periodic switching of the direct current output among the three-phase power modules. Instead of continuously outputting DC through one specific phase combination, the system periodically alternates between different phase combinations, distributing the thermal load across all power modules over time. This prevents concentrated overheating while maintaining the hill hold function.
Solution Approach 2:
The patent changes the operating parameters of the inverter by dynamically adjusting which switching elements are activated and how the direct current is distributed among phases. By modifying the switching patterns and current distribution parameters, the system maintains hill hold capability while preventing thermal concentration in any single power module.
2Reliability
If unbalanced direct current flows through power modules, then hill hold state is achieved, but excessive current concentrates in specific phases causing damage
Solution Approach 1:
The patent applies local quality by treating each phase differently through selective switching. Different phase combinations are activated at different time intervals, ensuring that no single phase continuously bears the full burden of the direct current output. This localized variation in current distribution prevents harmful current concentration.
Solution Approach 2:
The system periodically rotates which phases carry the direct current output, creating a time-varying current distribution pattern. This periodic redistribution ensures that excessive current is not permanently concentrated in any specific phase, thereby preventing damage while maintaining hill hold functionality.
3Temperature
If current compensation is applied to overheated switching elements, then overheating is mitigated, but current command complexity increases
Solution Approach 1:
The patent employs feedback mechanisms by monitoring the temperature or thermal state of switching elements and using this information to adjust the current commands. When a switching element is identified as overheated, the system provides feedback to modify the current distribution, reducing current to that element while redistributing it to cooler phases. This feedback-based approach mitigates overheating through a systematic but relatively simple control adjustment.
Data Source
AI summary
Provided is an apparatus and method for controlling an inverter to drive a motor installed in a vehicle, and a vehicle including the same. The apparatus includes a current command generation unit. The current command generation unit generates a current command based on a torque command, determines a current compensation value in response that the motor is in a hill hold state and a junction temperature of any of three-phase switching elements in the inverter exceeds a predetermined threshold temperature, and varies the current command based on the current compensation value and outputs the varied current command.