Compressor Stall Detection via Driving Circuit Temperature Rise
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Solution Overview
Problem
Existing compressor control devices face challenges in detecting and responding to stalled conditions quickly and efficiently, often leading to potential damage from overcurrents and high power consumption, with existing solutions like thermo-mechanical switches and series resistors being either slow or costly.
Innovation Solution
A compressor control device featuring a driving circuit, a temperature sensor thermally coupled to the driving circuit, and a control stage that selectively prevents coil supply based on a minimum temperature increment detected within a predetermined control time window, using a digital processing unit and a stall detector module to rapidly identify and respond to stall conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermo-mechanical switch is used to detect stalled compressor conditions, then the control device can protect against overcurrents, but the response is not sufficiently fast and power consumption remains high
Solution Approach 1:
The patent replaces the mechanical thermo-mechanical switch with an electronic temperature sensor and control circuit. The temperature sensor thermally couples to the control circuit to detect temperature changes, and the control circuit processes this information to detect stall conditions and control the power switch, eliminating the mechanical response limitations.
Solution Approach 2:
The patent monitors temperature changes over time by comparing temperature readings at different moments. The control circuit detects stall conditions by identifying when the temperature increment exceeds a threshold within a specific time window, enabling fast response to stall conditions without continuous high power consumption.
2Speed
If a series resistor is used to sense current, then timely reaction to stall conditions is achieved, but manufacturing costs increase and power consumption rises
Solution Approach 1:
The patent replaces the electrical current sensing method (series resistor) with thermal sensing. The temperature sensor detects temperature changes in the control circuit caused by overcurrent conditions, and the control circuit translates these temperature changes into stall detection, avoiding the continuous power consumption of resistive sensing.
Solution Approach 2:
The patent introduces temperature as an intermediary parameter to detect stall conditions. Instead of directly measuring current with a power-consuming resistor, the system uses temperature changes as an indirect indicator of overcurrent conditions, enabling timely detection with minimal power consumption.
3Measurement precision
If phase shift detection is used to detect stalled conditions, then accurate detection is achieved, but device complexity and size increase
Solution Approach 1:
The patent replaces complex electrical phase shift detection circuits with a simple temperature-based detection system. The temperature sensor and control circuit provide accurate stall detection by monitoring temperature changes, eliminating the need for special processing units and dedicated phase-sensing components.
Solution Approach 2:
The patent changes the detection parameter from electrical phase shift to temperature change. This parameter change simplifies the detection mechanism while maintaining accuracy, as temperature changes provide a direct indicator of stall conditions without requiring complex signal processing.
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
This solution effectively prevents overheating and potential damage by quickly identifying compressor stalls through temperature monitoring, reducing power consumption and manufacturing costs, while maintaining reliability and precision across varying environmental conditions.
Implementation Method 1
a temperature sensor, thermally coupled to the driving circuit for providing a temperature sensing signal correlated to a temperature in the driving circuit
Data Source
AI summary
A compressor control device includes a driving circuit, for controllably supplying a coil of an electric motor of a compressor. A temperature sensor is thermally coupled to the driving circuit and provides a temperature sensing signal correlated to a temperature in the driving circuit. A control stage, coupled to the driving circuit and to the temperature sensor, selectively prevents the driving circuit from supplying the coil, in response to a minimum temperature increment being detected by the temperature sensor within a pre-determined control time window.