Analog Compressor Control Circuit for Battery-Powered AC Duration
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Solution Overview
Problem
Existing vehicle air conditioning systems that rely on auxiliary batteries for operation when the engine is off have limited duration due to battery capacity constraints, necessitating a solution to maximize run time while minimizing power consumption.
Innovation Solution
An auxiliary air conditioning system with a variable speed compressor and analog control circuit that adjusts compressor speed based on air temperature changes, using an auxiliary battery bank and a temperature sensor to generate control signals, thereby optimizing power usage and maintaining a setpoint temperature with low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the auxiliary air conditioning system operates with a fixed speed compressor, then the system structure is simple, but the power consumption is high and operational duration is limited
Solution Approach 1:
The patent applies a variable speed compressor that dynamically adjusts its operating speed based on real-time temperature feedback from temperature sensors. The compressor motor speed is modulated to match the actual cooling demand, allowing the system to extend operational duration by consuming only the necessary power rather than operating at fixed high speed continuously.
Solution Approach 2:
The system changes the operational parameters of the compressor by varying its speed according to temperature differential between the interior and exterior environments. When the temperature difference is small, the compressor operates at lower speed; when the difference is large, it increases speed, thereby optimizing power consumption across different operating conditions to extend battery duration.
2Measurement precision
If a microprocessor-based control system is used, then the temperature control precision is high, but the device complexity and cost increase
Solution Approach 1:
The patent replaces the electronic microprocessor-based control system with an analog control circuit that uses continuous electrical signals to regulate compressor operation. The analog circuit processes temperature sensor signals and generates motor control signals through continuous voltage/current relationships, achieving sufficient temperature control precision without the complexity, cost, and power consumption of digital microprocessors.
Solution Approach 2:
The analog control circuit operates autonomously using continuous feedback from temperature sensors to automatically adjust compressor speed without requiring external processing or programming. The circuit self-regulates the system based on real-time conditions, eliminating the need for microprocessors while maintaining effective temperature control.
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 effectively extends the operational duration of the auxiliary air conditioning by minimizing power consumption while maintaining a consistent temperature, enhancing reliability and simplicity through analog control, independent of microprocessor requirements.
Implementation Method 1
a temperature sensor connected to the auxiliary battery bank to receive the supply voltage via a first terminal thereof to generate a variable voltage at a second terminal thereof based on an air temperature
Implementation Method 2
an operational amplifier including first input coupled to the input line and a second input coupled to an output of the operational amplifier
Implementation Method 3
a first voltage regulator parallel to the output line, the first voltage regulator including a reference input connected to the output line via the node so as to produce a constant voltage output having a current depending on a variable voltage at the output
Implementation Method 4
The compressor includes a variable speed motor configured to pressurize refrigerant vapor received from the evaporator coil via the refrigerant conduit
Data Source
AI summary
The auxiliary AC system includes a temperature measurement device configured to generate a variable output based on an air temperature in an environment proximate to the AC system and a compressor control circuit communicably coupled to a variable speed motor. The compressor control circuit is configured to receive the variable output from the temperature measurement device, determine that the output indicates a change in the air temperature, and generate a control signal for the variable speed motor, the control signal including a current having a magnitude depending on the extent of the change to vary a rate at which a compressor pressurizes a refrigerant vapor.