System and method for cooling power electronics of refrigerant compressors
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Solution Overview
Problem
Refrigerant compressors lack effective cooling solutions for their power electronics, particularly during startup, leading to sudden current flows and potential overheating.
Innovation Solution
A refrigerant system with multiple cooling lines, including an electromechanically operated valve and a thermal exchange unit, directs refrigerant to cool insulated-gate bipolar transistors (IGBTs), silicon-controlled rectifiers (SCRs), and soft start circuits, with a controller managing the flow to prevent sudden current surges and maintain optimal temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If refrigerant is directed to cool power electronics during startup, then temperature control is improved, but sudden current flows occur
Solution Approach 1:
The soft start circuit is activated before the compressor motor starts, gradually increasing the refrigerant flow to power electronics while limiting inrush current. The electromechanically operated valve opens progressively during the startup sequence, allowing cooling to begin before full power is applied to the motor, thus preventing thermal shock and current surges.
Solution Approach 2:
The system uses an electromechanically operated valve that can dynamically adjust refrigerant flow rate based on operational phase. During startup, the valve opens gradually rather than fully, and during normal operation, it modulates flow to match thermal demands. This dynamic control prevents sudden current flows while maintaining optimal cooling.
2Temperature
If multiple cooling lines are added to cool different components, then cooling effectiveness is improved, but device complexity increases
Solution Approach 1:
The cooling system is segmented into three separate cooling lines, each dedicated to a specific component or component group: one line for power electronics, one for the motor, and one for the soft start circuit. This segmentation allows independent optimization of cooling flow to each component while maintaining a unified refrigerant distribution system through a common source and parallel architecture.
Solution Approach 2:
A single refrigerant distribution system serves multiple functions by branching into parallel cooling lines that can independently cool different components. The common source and valve assembly provide universal cooling capability, while the parallel line structure allows each branch to be optimized for its specific thermal requirements without requiring separate refrigerant loops.
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 cools critical components, preventing sudden current flows and maintaining optimal temperatures, thereby enhancing the reliability and efficiency of refrigerant compressors.
Implementation Method 1
refrigerant from the main loop to the motor and/or the power electronics
Implementation Method 2
conveying refrigerant from the main loop to the motor and/or the power electronics
Implementation Method 3
an electromechanically operated valve selectively opened in response to instructions from a controller
Implementation Method 4
the thermal exchange unit includes an evaporator adjacent a blower
Implementation Method 5
the thermal exchange unit includes an evaporator adjacent a blower
Data Source
AI summary
This disclosure relates to refrigerant compressors, and, in particular, relates to cooling for the power electronics of such compressors. An example refrigerant system includes a main refrigerant loop in communication with a condenser, an evaporator, and a compressor. The refrigerant system further includes at least one cooling line configured to direct refrigerant from the main refrigerant loop to cool a chamber containing electronic components. A method is also disclosed.