Multi-pulse constant voltage transformer for a variable speed drive in chiller applications
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing transformer technologies fail to provide a constant voltage output across a range of input voltages in variable speed drive systems for chiller applications, leading to harmonic distortion and inefficiencies, particularly in global applications with varying utility grid voltages.
Innovation Solution
A multi-pulse transformer with multiple taps on primary or secondary windings, which converts input AC power to sinusoidal output voltage waves with phase shifts, ensuring a constant AC output voltage magnitude across varying input voltages, and integrates with a DC link and inverter to provide variable voltage and frequency output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional transformer is used to convert input AC voltage to output AC voltage, then the transformer structure is simple, but the output voltage cannot remain constant across varying input voltages and harmonic distortion occurs
Solution Approach 1:
The transformer is divided into multiple primary windings (first, second, third primary windings) with different tap configurations, allowing selective connection to maintain constant output voltage across varying input voltages. This segmentation enables the transformer to handle different input voltage ranges effectively while reducing harmonic distortion.
Solution Approach 2:
The transformer incorporates dynamic tap switching capability where different primary winding configurations can be selectively engaged based on input voltage conditions. This dynamic adjustment allows the transformer to adapt to varying input voltages and maintain stable output voltage, resolving the contradiction between simplicity and performance.
2Reliability
If multiple pulse transformer with multiple taps is used to provide constant voltage output, then output voltage stability improves, but device complexity increases
Solution Approach 1:
The transformer design provides multiple functions within a single device: it can handle different input voltage ranges (e.g., 208V, 230V, 460V, 480V), provide constant voltage output, and reduce harmonic distortion simultaneously. The multiple primary windings with different tap configurations enable the transformer to serve multiple voltage conversion purposes without requiring separate transformers for each application.
3Ease of manufacture
If conventional transformer is used in variable speed drive system, then system cost is lower, but power quality and efficiency deteriorate due to harmonic distortion
Solution Approach 1:
The transformer converts the potentially harmful effect of varying input voltages and harmonic distortion into beneficial outcomes by using multiple primary windings with tap configurations. The design transforms what would be problematic voltage variations into controlled, stable output voltage while reducing harmonic content in the input current, effectively converting potential harm into system benefits.
4Adaptability or versatility
If single transformer design is used for global applications, then device simplicity is maintained, but adaptability to different utility grid voltages is limited
Solution Approach 1:
The transformer is designed with universal applicability to different global voltage standards through its multiple primary windings configured with various tap settings. The first, second, and third primary windings can be selectively connected to accommodate different input voltage ranges found in various countries, making the transformer adaptable to global applications while maintaining a single device design.
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 solution provides a cost-effective, efficient, and globally applicable variable speed drive system with reduced input current harmonics, improved power quality, and increased efficiency by maintaining a constant AC output voltage across different input voltages, enabling the use of a single motor family for all applications and optimizing system cost and size.
Implementation Method 1
A multi-pulse transformer with multiple taps on primary or secondary windings, which converts input AC power to sinusoidal output voltage waves with phase shifts
Data Source
AI summary
A multi-pulse transformer with multiple taps provides a constant magnitude voltage output to a variable speed chiller's compressor motor over a range of input voltages. The 3-phase transformer includes primary windings and a plurality of secondary windings. The secondary windings are electromagnetically coupled with the associated primary winding. The primary windings include taps for receiving multiple input AC voltages and the secondary windings have a single output terminal for supplying a predetermined output voltage which, after rectification produces a DC multi-pulse waveform for powering a DC link of a variable speed drive. Alternatively the 3-phase transformer includes multiple taps on the secondary windings. Each of the primary windings has a terminal for receiving an input AC voltage. The taps of the secondary windings provide an output voltage that is converted to a multi-pulse waveform for powering a DC link of a variable speed drive.