EV Heat Pump Compressor Control for Cabin Heating Load
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Solution Overview
Problem
Battery electric vehicles (BEVs) rely on resistive heaters or heat pumps to heat the cabin, which reduces the vehicle's range due to the use of battery power for heating.
Innovation Solution
A vapor compression heat transfer system with a compressor, condenser, and electronic expansion valves is controlled using feedforward and feedback control to manage heat load and temperature, optimizing energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a heat pump is used to heat the cabin, then heating efficiency is improved, but energy consumption increases due to dynamic control operations
Solution Approach 1:
The patent implements dynamic control of the heat pump system by continuously adjusting the compressor speed based on real-time heat load calculations. The controller modifies operational parameters (compressor speed, expansion valve positions) dynamically rather than using fixed settings, allowing the system to adapt to changing thermal conditions and minimize energy consumption while maintaining heating efficiency.
Solution Approach 2:
The system employs feedback control by monitoring outlet air temperature and using it to calculate the required heat load. The controller continuously compares the actual temperature with the target temperature and adjusts the compressor speed and expansion valve positions accordingly. This closed-loop feedback mechanism ensures optimal energy usage by only providing the necessary heating power required to maintain the desired cabin temperature.
2Productivity
If compressor speed is increased to meet heat load demand, then heating performance is improved, but energy consumption increases
Solution Approach 1:
The patent implements dynamic control of the heat pump system by continuously adjusting the compressor speed based on real-time heat load calculations. The controller modifies operational parameters (compressor speed, expansion valve positions) dynamically rather than using fixed settings, allowing the system to adapt to changing thermal conditions and minimize energy consumption while maintaining heating efficiency.
Solution Approach 2:
The system changes operational parameters (compressor speed, electronic expansion valve positions) based on calculated heat load requirements. Instead of operating at fixed speeds, the compressor speed is continuously adjusted as a variable parameter to match the actual heating demand, thereby optimizing the balance between heating performance and energy consumption.
3Use of energy by moving object
If dynamic control with multiple sensors and actuators is implemented, then heating efficiency is improved, but device complexity increases
Solution Approach 1:
The controller serves multiple functions within a single integrated unit: it receives temperature sensor inputs, calculates heat load based on thermal models, determines optimal compressor speed, controls electronic expansion valves, and monitors system performance. This multi-functional approach consolidates what could be separate systems into one universal control unit, improving heating efficiency while limiting the increase in overall device complexity.
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
Enhances cabin heating efficiency, reducing energy consumption and maintaining vehicle range by dynamically controlling the heat pump's operation based on heat load and temperature feedback.
Implementation Method 1
a compressor configured to compress a refrigerant
Implementation Method 2
a condenser coupled to an outlet of the compressor and configured to receive air flow from a space
Data Source
AI summary
A vapor compression heat transfer system includes a compressor configured to compress a refrigerant and a condenser coupled to an outlet of the compressor and configured to receive air flow from a space, the condenser including an inlet air temperature sensor and an outlet air temperature sensor. One or more electronic expansion valves (EXVs) coupled to the outlet of the condenser. One or more heat exchangers are coupled to outlets of the one or more EXVs. A controller is configured to calculate a heat load of the condenser according to current heat transfer from the condenser to the space and an amount of heat transfer calculated to change an output of the outlet air temperature sensor to a target air temperature at a target rate. The controller at least partially controls a speed of the compressor to achieve the heat load at the condenser. Feedback control is also used to control the speed of the compressor, such as based on sensed temperature of the refrigerant, air in the space, or other temperature.