Two-Wire Compressor Controller Using Capacitor Power Storage
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Solution Overview
Problem
Conventional climate-control systems with three-wire schemes require additional installation effort and cost due to the need for a separate power wire from the thermostat to the outdoor control unit, limiting efficiency in energy usage and installation convenience.
Innovation Solution
A two-wire climate-control system where a power converter generates power from the demand signal and charges a capacitor, allowing the system to operate without continuous power supply from the thermostat, enabling efficient compressor control based on normalized thermal load and slope data stored in a nonvolatile memory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a three-wire scheme is used with a separate power wire from thermostat to outdoor control unit, then the controller can continuously receive power and control data, but the installation complexity and cost increase
Solution Approach 1:
The patent combines the power signal and demand signal into a single two-wire configuration. The converter circuit integrates both power conversion and capacitor charging functions, eliminating the need for separate power and signal wires while maintaining reliable controller operation throughout the demand cycle and intermediate period.
Solution Approach 2:
The capacitor is charged in advance during the demand cycle when power is available, storing energy before the intermediate period begins. This preliminary energy storage ensures the controller can operate without interruption during the time between demand cycles, maintaining reliability without requiring continuous power wiring.
2Device complexity
If a two-wire scheme is used without continuous power supply, then installation complexity is reduced, but the controller must operate with intermittent power availability
Solution Approach 1:
The system operates in periodic cycles: during the demand cycle, the converter charges the capacitor and powers the controller; during the intermediate period, the capacitor discharges to maintain controller operation. This periodic charge-discharge pattern ensures continuous energy availability despite intermittent power input.
Solution Approach 2:
The capacitor acts as an energy intermediary, decoupling the intermittent power input from the controller's continuous power requirements. It buffers energy during the demand cycle and releases it during the intermediate period, ensuring uninterrupted controller operation without requiring complex power management circuitry.
3Productivity
If the compressor operates continuously at high capacity, then cooling demand is met faster, but energy consumption increases
Solution Approach 1:
The controller dynamically adjusts compressor capacity based on real-time thermal load conditions. By monitoring temperature differentials and calculating cooling demands, the system switches between high and low capacity modes appropriately, optimizing the balance between cooling speed and energy consumption rather than operating continuously at fixed capacity.
Solution Approach 2:
The system changes operational parameters (compressor capacity level) based on measured thermal conditions. When thermal load exceeds thresholds, the controller increases compressor capacity; when demand is lower, it reduces capacity, thereby adapting energy consumption to actual cooling needs and avoiding unnecessary energy expenditure.
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 two-wire system reduces installation complexity and energy consumption by optimizing compressor operation based on thermal load and slope analysis, maintaining comfort while minimizing high-capacity mode usage and energy expenditure.
Implementation Method 1
a power converter generates power from the demand signal and charges a capacitor
Data Source
AI summary
A system includes a converter and a controller to control a compressor and operates without receiving power supply from a thermostat. The converter receives a demand signal from the thermostat that is used to power the controller and charge a capacitor. When the thermostat de-asserts the demand signal, the charged capacitor powers the controller, which saves system parameters in a nonvolatile memory and enters a power save mode. The life of the nonvolatile memory is extended by alternately storing the system parameters in different memory locations. The system normalizes outdoor ambient temperature (OAT) during a demand cycle. The system determines OAT slope, which is used to select durations to operate the compressor at different capacities, by performing time based calculations during a demand cycle, demand cycle based calculations at the start of a demand cycle, or time and demand cycle based calculations during a demand cycle.