Controller Optimizes Phase Offsets for Switching Converters

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Solution Overview

Problem

Conventional power supply systems with multiple switching converters face challenges in optimally distributing switching phases to minimize input ripple current and radiated emissions, particularly as the number of converters increases, making manual selection of phase offsets impractical and slow to adjust to changes in load conditions.

Innovation Solution

A computationally efficient controller calculates and optimizes switching phase offsets for voltage converters by determining a switching order based on contributions to ripple current or voltage, ensuring consistent spacing of control pulses within a switching period to reduce ripple and emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual selection of phase offsets is used in power supply systems with multiple switching converters, then the system can be configured, but the process becomes impractical and slow as the number of converters increases

Engineering Contradiction:

Improvephase offset configurationVSAvoidnumber of converters

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The system automatically determines optimal phase offsets using a controller that calculates the contribution of each converter to ripple current and autonomously assigns phase offsets based on ranked contributions, eliminating the need for manual configuration even as the number of converters increases

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system dynamically adjusts phase offset parameters based on operating conditions by calculating ripple current contributions and reassigning phases according to changing load conditions, making the configuration adaptive rather than static

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If switching phases are synchronized in multiple voltage converters, then the control is simple, but large ripple current in the intermediate bus and high radiated emissions occur

Engineering Contradiction:

Improvecontrol simplicityVSAvoidripple current and radiated emissions

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The system introduces periodic phase offsets between converters based on their ranked contributions to ripple current, distributing switching edges uniformly across the switching period to reduce peak currents and radiated emissions while maintaining controlled operation

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system applies different phase offset strategies to different converters based on their individual contributions to ripple current, with higher-ranked converters receiving different phase treatment than lower-ranked ones, optimizing the overall system performance

Inventive Principle:

Principle #3Local quality

3Object-generated harmful factors

If phase spreading is implemented by allowing converters to operate from internally generated clocks, then switching pulse edges are randomized, but the control precision and consistency are reduced

Engineering Contradiction:

Improvepeak current reductionVSAvoidswitching phase control precision

Core Design Contradiction:

Object-generated harmful factorsVSMeasurement precision

Solution Approach 1:

The system introduces a central controller as an intermediary that generates reference clocks and calculates optimal phase offsets, which are then applied to individual converters, maintaining both the phase spreading benefits and precise controlled operation through the mediating controller

Inventive Principle:

Principle #24Intermediary (Mediator)

4Power

If the number of voltage converters in the power supply system increases, then the power delivery capability improves, but the difficulty of manually selecting optimal phase offsets increases dramatically

Engineering Contradiction:

Improvepower delivery capabilityVSAvoidphase offset optimization difficulty

Core Design Contradiction:

PowerVSDifficulty of detecting and measuring

Solution Approach 1:

The system uses feedback from measured or calculated ripple current contributions from each converter to automatically determine optimal phase offsets, with the controller continuously monitoring and adjusting phases based on actual performance rather than manual preconfiguration

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS9954428B2Determination of phase offsets in a supply system having multiple switching converters

Publication Date: 2018.04.24 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A controller, and related method, to control switching elements of a plurality of voltage converters of a power system. The controller receives a signal representing an operating condition that indicates a contribution of each of the plurality of voltage converters to a ripple component of an input current or an input voltage of the power system. The controller ranks the plurality of voltage converters based on the contribution of each of the plurality of voltage converters to the ripple component. The controller calculates a switching phase offset for each switching element of the plurality of voltage converters by determining a switching order for each switching element of the plurality of voltage converters based on an alternating extremum contribution to the ripple component, and arranging control signals for each switching element of the plurality of voltage converters based on the switching order.