Vehicle Air Conditioning Compressor Speed Control
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Solution Overview
Problem
Existing air conditioning systems for motor vehicles fail to optimize compressor speed control effectively, leading to high electrical consumption and inefficient thermal comfort gain, with existing methods relying on unreliable measurement filters and dynamic values.
Innovation Solution
A control system for an air conditioning system with a compressor driven by an electric motor, which adjusts the compressor's rotation speed based on outside temperature, evaporator temperature setpoint, air flow, and refrigerant pressure, using maps and PI/PID regulation to minimize electrical power consumption while maintaining thermal comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the compressor speed is increased to improve thermal comfort, then the cooling performance is improved, but the electrical consumption increases
Solution Approach 1:
The patent implements dynamic speed control of the compressor by adjusting the electric motor's rotational speed based on real-time operating conditions. The control system continuously monitors parameters such as evaporator temperature, outside temperature, and air flow, then dynamically adjusts compressor speed to match actual cooling demands, avoiding both over-compression and under-compression scenarios
Solution Approach 2:
The patent changes the operational parameters of the compressor by using multiple maps (first map for thermal comfort, second map for electrical consumption) that define different speed limits based on outside temperature, evaporator temperature setpoint, and air flow conditions. The control system selects and switches between these parameter sets to optimize the balance between cooling performance and energy consumption
2Use of energy by moving object
If the compressor speed is decreased to reduce electrical consumption, then the electrical power usage is reduced, but the thermal comfort performance deteriorates
Solution Approach 1:
The patent applies partial action by using two distinct speed limit maps: a first map that ensures minimum thermal comfort requirements are met, and a second map that optimizes for electrical consumption reduction. The control system determines when to apply each map based on current operating conditions, applying partial compression when full cooling capacity is not needed, thereby reducing energy consumption while maintaining acceptable thermal comfort
Solution Approach 2:
The system dynamically switches between different control strategies based on real-time conditions. When electrical consumption needs to be reduced, the system transitions to the second map with lower speed limits, while continuously monitoring to ensure thermal comfort remains within acceptable parameters, allowing flexible adaptation to changing priorities
3Speed
If the compressor speed is controlled using dynamic values and measurement filtering, then the control responsiveness is improved, but the measurement reliability and detection accuracy deteriorate
Solution Approach 1:
The patent establishes predetermined speed limits through pre-defined maps that are calculated based on theoretical relationships between compressor speed, evaporator temperature, outside temperature, and air flow. These pre-calculated maps serve as reference guides that eliminate the need for complex real-time measurement filtering, providing reliable control boundaries without compromising measurement accuracy
Solution Approach 2:
The patent introduces maps as intermediary elements that mediate between raw sensor measurements and control decisions. Rather than directly using potentially noisy measurement data for control adjustments, the system uses the maps to translate desired thermal comfort and energy consumption targets into appropriate speed limits, filtering out measurement uncertainties through the intermediary mapping relationship
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
The system efficiently estimates the benefit of electrical consumption in terms of thermal comfort gain by dynamically adjusting compressor speed, optimizing thermal performance and reducing electrical power usage, thereby integrating a compromise between thermal performance and electrical consumption.
Implementation Method 1
The fluid then passes through the evaporator which allows heat to be exchanged from the outside with the fluid
Implementation Method 2
The fluid is then vaporized and continues its journey to the compressor
Implementation Method 3
The condenser allows the heat contained in the refrigerant to be exchanged with the outside
Implementation Method 4
The compressor increases the pressure of the refrigerant in gaseous form and circulates it to the condenser
Data Source
Figure 1~3
Figure 4
AI summary
The invention relates to a system for controlling an air conditioning system installed in a motor vehicle, comprising an evaporator and a compressor driven by an electric motor having a controlled rotation speed. The control system comprises: a means (2) for developing a compressor limit rotation speed as a function of the outside temperature and the temperature setpoint of the evaporator; a means (5) for developing a compressor rotation speed setpoint as a function of the limit rotation speed of the compressor; and means for controlling the rotation speed of the electric motor as a function of the compressor rotation speed setpoint.