Coil Switching Device for Rotary Machine Driving System

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Solution Overview

Problem

The existing coil switching devices for rotary machines in vehicles are bulky and costly due to complex configurations and large conductor areas required for high currents, which hinders miniaturization and cost reduction.

Innovation Solution

A rotary machine driving system with a coil switching device featuring a movable portion driven by an actuator, using simple rectangular parallelepiped or cylindrical conductors for short-circuiting coil ends, allowing for efficient switching between series and parallel connections based on rotation speed, thereby reducing size and manufacturing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a coil switching device with complex configuration and large conductor area is used to handle high currents, then the rotary machine can operate in wide rotation range with optimized efficiency, but the size and cost of the device increases significantly

Engineering Contradiction:

Improverotation rangeVSAvoidcoil switching device size

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The coil switching device is segmented into multiple independent switching units, each handling a specific phase or coil group. This segmentation allows the device to manage high currents through distributed switching elements rather than requiring a single large conductor, thereby reducing overall device volume while maintaining adaptability across wide rotation ranges.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The coil switching device employs dynamic switching mechanisms that adapt the connection configuration based on rotation speed requirements. By using movable contacts and reconfigurable circuit paths, the device can transition between different switching states without requiring large fixed conductor areas, thus reducing size while preserving versatility for both low-speed and high-speed operation.

Inventive Principle:

Principle #15Dynamics

2Power

If complex bending processing and assembling of bus bar is performed to cope with large current, then the current handling capability is improved, but the manufacturing cost increases significantly

Engineering Contradiction:

Improvecurrent handling capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

PowerVSEase of manufacture

Solution Approach 1:

The invention replaces expensive, complexly-processed bus bars with simpler, more economical switching elements that can be manufactured through standard processes. The switching device uses readily available components with simple geometries that require minimal bending or special assembly, significantly reducing manufacturing costs while maintaining adequate current handling capability through proper switching configuration.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention substitutes mechanical bus bar connections with electrical switching mechanisms controlled by semiconductor devices or simple contactors. This substitution eliminates the need for complex mechanical bending and assembly of large conductors, reducing manufacturing complexity and cost while achieving the same current handling function through controlled electrical paths.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If relay device is used to configure switching device, then the switching function is achieved, but the size and cost increase with increasing current

Engineering Contradiction:

Improveswitching functionVSAvoidswitching device size

Core Design Contradiction:

Ease of operationVSVolume of moving object

Solution Approach 1:

The invention replaces mechanical relay devices with solid-state switching elements such as transistors, IGBTs, or MOSFETs that can handle high currents without increasing in size proportionally. These semiconductor-based switches provide the same switching function as relays but with much smaller form factors and without the current-dependent size increase characteristic of electromagnetic relays.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The switching device employs universal semiconductor switching elements that can handle a wide range of current levels without requiring different device sizes. A single switching module design can accommodate varying current requirements through parameter optimization rather than physical scaling, unlike relay devices that must be oversized to handle peak currents.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11601082B2Rotary machine driving system and vehicle

Publication Date: 2023.03.07 HITACHI LTD

AI summary

A rotary machine driving system includes: a rotary machine including a plurality of coils; an inverter device configured to operate the rotary machine at a variable speed, including a control device for controlling power conversion by an inverter circuit, and a coil switching device for switching a connection of the coils according to the control device. The control device commands the coil switching device to switch the connection of the coils when rotation of the rotary machine transitions between a low-speed rotation range and a high-speed rotation range due to acceleration and deceleration. A starting end and a terminal end of at least one set of coils per phase of the rotary machine are drawn out in a freely connectable state. The coil switching device includes at least one movable portion driven by one actuator.