Variable speed drive with secondary windings

Solution Overview

Problem

Current variable speed drives (VSDs) in medium voltage systems require external step-down transformers, leading to increased costs and footprint due to external wiring and components, especially when switching from a fixed voltage source to an alternate fixed-speed source.

Innovation Solution

Incorporating a second secondary winding within the VSD transformer allows for internal switching of the power source from a variable voltage to a fixed voltage, eliminating the need for an external transformer and associated components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If an external step down transformer is used to supply fixed voltage to the motor, then the motor can operate at threshold speed conditions, but the system footprint and cost increase due to external wiring and components

Engineering Contradiction:

Improvemotor operation at threshold speedVSAvoidsystem footprint

Core Design Contradiction:

Ease of operationVSArea of stationary object

Solution Approach 1:

The patent combines the external step-down transformer and its associated wiring into the VSD housing by integrating a secondary winding onto the existing transformer core. This merging eliminates the need for separate external transformer components and reduces system footprint while maintaining the ability to supply fixed voltage to the motor at threshold speed conditions.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The transformer in the VSD is designed to serve multiple functions: it provides both variable voltage output through the primary secondary winding for normal VSD operation and fixed voltage output through an added secondary winding for threshold speed conditions. This multi-functionality eliminates the need for a separate dedicated transformer for fixed voltage supply.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of operation

If an external step down transformer is used to supply fixed voltage to the motor, then the motor can operate at threshold speed conditions, but the system cost increases due to external wiring and components

Engineering Contradiction:

Improvemotor operation at threshold speedVSAvoidsystem cost

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

The patent combines the external step-down transformer and its associated wiring into the VSD housing by integrating a secondary winding onto the existing transformer core. This merging eliminates the need for separate external transformer components and reduces system footprint while maintaining the ability to supply fixed voltage to the motor at threshold speed conditions.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The transformer in the VSD is designed to serve multiple functions: it provides both variable voltage output through the primary secondary winding for normal VSD operation and fixed voltage output through an added secondary winding for threshold speed conditions. This multi-functionality eliminates the need for a separate dedicated transformer for fixed voltage supply.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If a traditional VSD with single secondary winding is used, then the system has simpler structure, but it cannot efficiently supply power at threshold speed conditions without external transformer

Engineering Contradiction:

Improvetransformer structureVSAvoidpower supply at threshold speed

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The transformer in the VSD is designed to serve multiple functions: it provides both variable voltage output through the primary secondary winding for normal VSD operation and fixed voltage output through an added secondary winding for threshold speed conditions. This multi-functionality eliminates the need for a separate dedicated transformer for fixed voltage supply.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 reduces system costs and electrical losses by enabling efficient power supply to motors at threshold speed conditions, enhancing overall system efficiency and reducing the footprint of chiller systems.

Implementation Method 1

a primary winding of a step down transformer coupled to an alternating current (AC) power source, a first secondary winding of the step down transformer, where the first secondary winding is configured to supply power at a variable supplied voltage to the motor

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS11512885B2Variable speed drive with secondary windings

Publication Date: 2022.11.29 TYCO FIRE & SECURITY GMBH

AI summary

Embodiments of the present disclosure relate to a refrigeration system that includes a compressor configured to circulate refrigerant along a refrigerant loop, a motor configured to drive the compressor, and a variable speed drive coupled to the motor and configured to supply power to the motor. The variable speed drive includes a primary winding of a step down transformer coupled to an alternating current (AC) power source, a first secondary winding of the step down transformer, where the first secondary winding is configured to supply power at a variable supplied voltage to the motor when the motor operates below a threshold voltage, and a second secondary winding of the step down transformer, where the second secondary winding is configured to supply power at a fixed supplied voltage when the motor operates at or above the threshold voltage.