Driving System Single Connection Route Circulating Currents

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Solution Overview

Problem

The existing driving systems with alternating-current rotary electrical machines face issues of deteriorated controllability and increased loss due to potential differences in electrical paths and circulating currents, which affect the efficiency and control of motor generators.

Innovation Solution

A driving system configuration that includes a step-up converter to raise the output voltage of a direct-current power source and connect it to both first and second inverters, while ensuring the second direct-current power source and first alternating-current rotary electrical machine are connected by a single route, preventing circulating currents and optimizing power distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the second direct-current power source and the first alternating-current rotary electrical machine are connected via multiple inverters and electrical paths, then power distribution flexibility is improved, but circulating currents occur and controllability deteriorates

Engineering Contradiction:

Improvepower distribution flexibilityVSAvoidcontrollability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces a single connection route as an intermediary path between the second direct-current power source and the first alternating-current rotary electrical machine. This single route acts as a mediator that eliminates circulating currents while maintaining power distribution capability, resolving the contradiction between flexibility and controllability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multiple inverters are used to connect power sources to motor generators, then power supply versatility is improved, but loss increases due to circulating currents

Engineering Contradiction:

Improvepower supply versatilityVSAvoidloss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent converts the potential harm of complex multi-inverter connections into benefit by identifying and implementing a single connection route. This approach eliminates circulating currents and energy loss while preserving the versatility benefits of having multiple inverters for other power distribution needs.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Adaptability or versatility

If a step-up converter is used to raise output voltage and connect to both inverters, then voltage compatibility is improved, but component size increases

Engineering Contradiction:

Improvevoltage compatibilityVSAvoidstep-up converter size

Core Design Contradiction:

Adaptability or versatilityVSVolume of stationary object

Solution Approach 1:

The patent applies partial action by implementing the step-up converter only where necessary in the single connection route, rather than in all possible connection paths. This selective approach maintains voltage compatibility where needed while minimizing the overall size and complexity of the power conversion system.

Inventive Principle:

Principle #16Partial or excessive action

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 configuration enhances controllability and reduces losses by eliminating circulating currents and minimizing current flow through electrical paths, leading to improved efficiency and downsizing of components like the step-up converter.

Implementation Method 1

a step-up converter that raises an output voltage of the first direct-current power source and outputs the output voltage to the first inverter and the second inverter

Methodology Applied

Scientific EffectVoltage conversion:

Data Source

PatentUS11214153B2Driving system

Publication Date: 2022.01.04 DENSO CORP

AI summary

A driving system includes a first alternating-current rotary electrical machine and a second alternating-current rotary electrical machine. The driving system includes: a first inverter electrically connected to the first alternating-current rotary electrical machine; a second inverter electrically connected to a first end of each of phase windings constituting the second alternating-current rotary electrical machine; a step-up converter; and a third inverter that is electrically connected to a second end of each of the phase windings and transfers power to a second direct-current power source different from the first direct-current power source to drive the second alternating-current rotary electrical machine. The step-up converter raises an output voltage of the first direct-current power source and outputs the output voltage to the first inverter and the second inverter. The second direct-current power source and the first alternating-current rotary electrical machine are connected by a single connection route.