EV Battery and Cabin Cooling With Suction Pressure Control
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Solution Overview
Problem
Electric vehicle cooling systems face challenges in maintaining uninterrupted and smooth thermal management, particularly when transitioning between cabin-only, battery-only, and hybrid cooling modes, leading to fluctuations in cabin and battery coolant temperatures and compressor operation delays.
Innovation Solution
A control circuitry-based method that determines a compressor suction pressure target and generates control signals using feedforward and feedback signals to adjust compressor suction pressure, allowing for seamless transitions between cooling modes and minimizing disturbances to the cabin and battery systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the cooling system transitions between cabin-only, battery-only, and hybrid cooling modes, then the system can meet diverse cooling demands, but temperature fluctuations and compressor operation delays occur
Solution Approach 1:
The system performs preliminary action by determining a target compressor suction pressure in advance before mode transitions occur. This target pressure is calculated based on anticipated cooling demands and used to generate feedforward control signals that proactively adjust compressor operation, preventing temperature fluctuations rather than reacting to them after they occur.
Solution Approach 2:
The system implements feedback control by continuously monitoring actual compressor suction pressure and comparing it to the target suction pressure. Feedback signals are generated based on the difference between actual and target values, and these signals are combined with feedforward signals to dynamically adjust compressor control, ensuring stable operation during mode transitions.
2Device complexity
If traditional cooling control methods are used, then the system structure remains simple, but compressor operation delays and cooling interruptions occur
Solution Approach 1:
The control system performs preliminary calculation of the target compressor suction pressure based on anticipated cooling requirements before mode transitions. This advance determination allows the compressor to be pre-positioned for optimal performance, eliminating delays that would occur with reactive control methods.
Solution Approach 2:
The system dynamically adjusts compressor control by combining feedforward and feedback signals in real-time. The control approach transitions from static, simple control to dynamic control that adapts to changing cooling demands while maintaining smooth operation, improving response efficiency without requiring complex hardware modifications.
3Reliability
If feedforward and feedback control signals are combined for precise compressor control, then temperature stability improves, but control system complexity increases
Solution Approach 1:
The system uses feedback control by monitoring actual compressor suction pressure and generating correction signals based on the difference from target values. This feedback mechanism provides automatic stabilization, maintaining temperature stability while using standard control components rather than complex custom-designed control systems.
Solution Approach 2:
The target compressor suction pressure serves as an intermediary parameter that mediates between cooling demands and compressor control. By using this intermediate target value, the system decouples the complex relationship between multiple cooling requirements and compressor operation, simplifying the control architecture while achieving precise temperature stability.
Data Source
AI summary
A vehicle includes a vehicle cooling system for cooling a cabin and a battery system, each having a respective target operating range. The cooling system is configured to select among a cabin-only mode, battery-only mode, or a hybrid cooling mode for cooling the cabin and the battery system. In the hybrid mode, the system determines a desired pressure at an inlet of a compressor corresponding to a suction pressure of the compressor, to avoid cooling interruptions. The system generates a control signal based on the desired suction pressure, and applies the control signal to the compressor. Generating the control signal may include generating a feedforward signal the desired suction pressure, generating a feedback signal based on the suction pressure, or a combination thereof. For example, the use of hybrid mode based on suction pressure allows smoother response to targets with reduced delays in response in meeting the cooling demands.