Mode switching for a centrifugal compressor
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Solution Overview
Problem
Centrifugal compressors in HVACR systems face limitations in energy and cost efficiency due to motor design constraints at partial-speed conditions, hindering the development of dual-mode systems that offer both ecological and economic benefits.
Innovation Solution
A permanent magnet motor with variable voltage taps and a VFD that switches between low-range and high-range voltage paths, along with wye-delta connections, to optimize motor operation for heating and cooling modes, enabling multiple configurations and operating points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If motors operate at partial-speed conditions, then energy efficiency is improved, but voltage decreases and current increases
Solution Approach 1:
The motor system dynamically switches between different winding configurations (wye-delta) and voltage ranges (low-range/high-range) based on operating conditions. This allows the motor to adapt its electrical characteristics to maintain optimal performance across varying speeds and loads, resolving the contradiction between energy efficiency at partial speed and adequate power output.
Solution Approach 2:
The invention changes key electrical parameters by switching between different voltage taps and winding connections. By varying the connection configuration (wye-delta switching) and selecting appropriate voltage ranges, the system modifies voltage, current, and impedance parameters to achieve both energy efficiency and sufficient power output at different operating points.
2Ease of manufacture
If component sizing is influenced by operating current at partial-speed conditions, then motor design is constrained, but flexibility for dual-mode operation is reduced
Solution Approach 1:
The motor is designed with multi-functionality to operate in both heating and cooling modes with a single component set. By incorporating switchable winding configurations and multiple voltage taps, the same motor components can serve multiple functions and adapt to different operating modes, eliminating the need for separate component sets for each mode.
Solution Approach 2:
The system uses dynamic switching between wye-delta connections and voltage ranges to provide adaptability across different operating modes. This dynamic reconfiguration allows the motor to maintain optimal performance characteristics for both heating and cooling applications without requiring separate component designs.
3Loss of energy
If voltage is reduced at partial-speed conditions, then energy consumption decreases, but power delivery capability is limited
Solution Approach 1:
The motor system dynamically adjusts its electrical configuration based on power delivery requirements. By switching between wye-delta connections and selecting appropriate voltage ranges, the system can optimize energy consumption during normal operation while maintaining the capability to deliver high power when needed through configuration changes.
Solution Approach 2:
The invention changes electrical parameters (voltage, current, impedance) through switching different winding configurations and voltage taps. This allows the system to reduce energy consumption during efficient operating conditions while maintaining power delivery capability by switching to configurations that provide higher voltage and current output when required.
Data Source
AI summary
The technologies described and recited herein pertain to a permanent magnet motor having multiple voltage taps so that the motor may run in multiple configurations, e.g., a low-range and a high-range, and have multiple optimal operating points.