Interleaved Boost Converter Overcurrent Sensing With Fewer Detectors

Solution Overview

Problem

The existing power supply configurations require a large number of current detectors, which increases device size, cost, and reduces reliability, especially when the number of switching elements is increased for higher interleaved phases.

Innovation Solution

A power supply with an even number of boost circuits, each including a reactor, switching element, and backflow prevention diode, utilizing a first-current detector and at least one second-current detector to detect a sum current across multiple boost circuits, with overcurrent determiners to stop operation when overcurrent is detected, thereby controlling the number of current detectors needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the number of current detectors is increased to match the number of switching elements for overcurrent detection, then the detection reliability is improved, but the device size and cost increase

Engineering Contradiction:

Improveovercurrent detection reliabilityVSAvoidnumber of current detectors

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the current detection function for multiple switching elements into a single common current detector. The detector measures the total current flowing through the power source, and the control unit calculates individual switching element currents by subtracting detected currents from reference currents, thereby detecting overcurrent conditions without requiring multiple physical current detectors.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The control unit acts as an intermediary that processes the total current measurement from the single current detector and derives individual switching element current information through calculation. This intermediary processing enables overcurrent detection for each switching element using a shared detection resource.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Power

If the number of switching elements is increased to increase interleaved phases for higher power output, then the power supply capability is improved, but the number of current detectors must also increase

Engineering Contradiction:

Improvepower supply capabilityVSAvoidnumber of current detectors

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The patent merges the current detection function for multiple switching elements into a single common current detector. The detector measures the total current flowing through the power source, and the control unit calculates individual switching element currents by subtracting detected currents from reference currents, thereby detecting overcurrent conditions without requiring multiple physical current detectors.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single current detector serves multiple functions by measuring the total current that contains information about all switching elements. The control unit processes this single measurement to monitor all switching elements simultaneously, making the detector universal for the entire power supply system rather than dedicated to a single element.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If a single common current detector is used to reduce the number of current detectors, then the device size and cost are reduced, but the ability to detect overcurrent in individual switching elements is compromised

Engineering Contradiction:

Improvenumber of current detectorsVSAvoidovercurrent detection capability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The control unit acts as an intermediary that processes the total current measurement from the single current detector and derives individual switching element current information through calculation. This intermediary processing enables overcurrent detection for each switching element using a shared detection resource.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system uses feedback from the single current detector's measurement of total current, combined with reference current information, to continuously monitor individual switching element currents. The control unit adjusts and calculates individual currents based on the feedback from the common detector, enabling reliable overcurrent detection despite using a single detection point.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11831230B2Power supply, motor driver, blower, compressor, and air conditioner

Publication Date: 2023.11.28 MITSUBISHI ELECTRIC CORP

AI summary

A power supply includes: a converter circuit including boost circuits, the converter circuit boosting a voltage output from a power source; a current detector that detects a first current flowing between the power source and the converter circuit; current detectors that each detect a second current, the second current being a sum current of currents flowing in switching elements of the boost circuits; and overcurrent determiners that determine whether the second currents are overcurrent on the basis of detection values of the second currents. When a result of the determination made by corresponding one of the overcurrent determiners indicates overcurrent, the boost circuits stop operating.