DC-DC Converter Control Device for Polarity-Switching Current

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Solution Overview

Problem

Existing control devices for direct current to direct current converters (DC-DC converters) face challenges in applying peak current mode control due to the opposite polarity of currents during voltage boost and voltage step-down control periods, making it difficult to maintain efficient reactor current adjustment.

Innovation Solution

A control device with a first and second control part, and an operation part that selects switch turning-on or turning-off instructions based on the polarity of the reactor current, transmitting these instructions to corresponding switches in the DC-DC converter to maintain peak current mode control during both voltage boost and voltage step-down periods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If peak current mode control is applied to DC-DC converter during voltage boost control period, then reactor current can be quickly adjusted to instruction current, but the control becomes difficult during voltage step-down control period due to opposite polarity of reactor current

Engineering Contradiction:

Improvereactor current adjustment speedVSAvoidcontrol applicability across different operating modes

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The control device is divided into a first control part that generates switching control signals during voltage boost control period and a second control part that generates switching control signals during voltage step-down control period. This segmentation allows each control part to be optimized for its specific operating mode, resolving the polarity issue by treating boost and step-down periods separately with dedicated control logic.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The control device dynamically switches between the first control part and the second control part based on the operating period. An operation part selects which control part to use depending on whether the DC-DC converter is in voltage boost mode or voltage step-down mode, enabling the system to adapt its control strategy to the current operating conditions and maintain effective current control throughout.

Inventive Principle:

Principle #15Dynamics

2Device complexity

If a single control part is used for both voltage boost and voltage step-down control, then device complexity is reduced, but control precision and stability deteriorate due to opposite current polarities

Engineering Contradiction:

Improvecontrol device structureVSAvoidreactor current control precision

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The operation part provides a universal selection mechanism that determines whether to use the first control part or the second control part based on the operating period. This multi-functional approach allows a single control device to effectively handle both voltage boost and voltage step-down operations with appropriate control strategies for each mode.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If switch turning instructions are not properly selected during polarity transition, then device complexity is reduced, but oscillations occur and control stability is lost

Engineering Contradiction:

Improvecontrol logic complexityVSAvoidcontrol stability

Core Design Contradiction:

Device complexityVSStability of the object's composition

Solution Approach 1:

The operation part proactively selects the appropriate control part before the polarity transition occurs by monitoring the operating period. This preliminary selection ensures that the correct control logic is in place before the current polarity changes, preventing control instability and oscillations that would occur with improper switch turning instructions during transition.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control device uses feedback from the operating period detection to dynamically determine which control part should be active. The operation part continuously monitors whether the DC-DC converter is in voltage boost mode or voltage step-down mode and adjusts the active control part accordingly, ensuring stable control throughout polarity transitions.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11183933B2Control device for DC-DC converter

Publication Date: 2021.11.23 DENSO CORP

AI summary

A control device has a first control part and a second control part. The control device is applied to a DC-DC converter. The control device selects a first switch turning-on instruction or a first switch turning-off instruction generated by the first control part during a voltage boost control period, and transmits the selected first switch turning-on instruction or the selected first switch turning-off instruction to a first switch in the DC-DC converter. The control device selects a second switch turning-on instruction or a second switch turning-off instruction generated by the second control part during a voltage step-down control period, and transmits the selected second switch turning-on instruction or the selected second switch turning-off instruction to a second switch in the DC-DC converter.