Motor Control Switch Device Eliminates In-Rush Currents

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional motor control systems face issues with in-rush currents damaging the motor and filter capacitor when the switch element is turned on, and high costs due to switch elements handling large currents.

Innovation Solution

A control system with a switch device comprising first and second switch circuits, where the second switch circuit receives a control signal to turn on or off the first switch circuit, allowing the driver to control the motor without continuous charging and discharging of the filter capacitor, thus eliminating in-rush currents and reducing the need for high-current handling components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the switch element is switched on from turned-off state, then the motor can be driven, but in-rush current damages the motor and filter capacitor

Engineering Contradiction:

Improvemotor driving capabilityVSAvoidin-rush current damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The switch element is divided into two separate switch circuits: a first switch circuit that continuously controls power supply to the driver, and a second switch circuit that controls the switching signal to the driver. This segmentation allows the first switch to operate continuously at lower current while the second switch handles the switching function, eliminating in-rush current damage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The driver circuit acts as an intermediary between the first switch circuit and the motor. It receives the control signal from the second switch circuit and translates it into appropriate driving signals for the motor, while being continuously powered by the first switch circuit, thus mediating the switching action without generating in-rush current.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the switch element handles larger current to enable switching operation, then the motor can be controlled, but the cost of the switch element increases

Engineering Contradiction:

Improveswitching control capabilityVSAvoidcomponent cost

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

The switching function is separated from the power supply function. The first switch circuit provides continuous low-current power supply, while the second switch circuit provides the control signal. This allows both switches to be smaller and less expensive than a single high-current switch, reducing overall component cost.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first switch circuit operates continuously to provide power, while the second switch circuit operates only when switching is needed. This partial operation allows the use of smaller, cheaper switch elements compared to requiring a single switch to handle all current continuously at full capacity.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS7495401B2Control systems and switch devices thereof

Publication Date: 2009.02.24 DELTA ELECTRONICS INC(CN)

AI summary

A control system for a motor. The control system and the motor receive an external power. The control system comprises a driver and a switch device. The driver is electrically connected to the motor. The switch device is electrically connected between the external power and the driver and turned on or off according to a control signal. The driver drives the motor according to the external power when the switch device is turned on.