Multiphase Power Converter Current Sensing and Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multiphase power converters face challenges in accurately sampling and controlling phase currents due to large current ripples, which are difficult to manage with digital signal processors, and achieving current balance among phases.
Innovation Solution
A multiphase converter system that includes terminal and low side bridge current sensors, a low pass filter to remove high frequency components, an over current protection device, and a system controller for accurate digital sampling and control, ensuring balanced phase currents and stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If digital signal processors are used to sample phase current, then control capability is improved, but measurement precision deteriorates due to large current ripple
Solution Approach 1:
The patent segments the current sensing function into two parts: terminal current sensing (for total current control) and low-side switch current sensing (for phase current balance). This segmentation allows each sensor to measure different aspects of current, avoiding the problem of directly sampling large ripple currents with digital processors.
Solution Approach 2:
The patent introduces low-pass filters as intermediary components between the current sensors and the digital signal processor. These filters act as mediators that remove high-frequency ripple components from the phase current signals before they reach the processor, enabling accurate digital sampling without being overwhelmed by large current variations.
2Ease of operation
If phase current is sampled directly, then current balance control is improved, but device complexity increases due to handling large ripple signals
Solution Approach 1:
The patent applies preliminary action by filtering out high-frequency ripple components from phase current signals before they are processed by the digital signal processor. The low-pass filters are positioned in the signal path to pre-process the currents, removing problematic ripple components ahead of time and simplifying subsequent digital processing operations.
3Speed
If high frequency components are retained in phase current signals, then dynamic response is improved, but stability deteriorates due to large current ripple
Solution Approach 1:
The patent applies parameter changes by carefully selecting and adjusting the cutoff frequencies of the low-pass filters to achieve an optimal balance between dynamic response and stability. By changing the filter parameters (cutoff frequency, filter order), the system can maintain adequate dynamic performance while effectively suppressing harmful high-frequency ripple that would otherwise compromise stability.
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
The system effectively controls total terminal current and balances phase currents, improving dynamic response and stability by processing only low ripple signals, thus enhancing the performance of multiphase power converters.
Implementation Method 1
a low pass filter for filtering out high frequency component of the low side switch current signal for each phase leg
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A multiphase converter (100) is disclosed. The multiphase converter (100) comprises multiple phase legs. Each leg has a combination of power semiconductors. The multiphase converter (100) further comprises a terminal current sensor (130) configured to generate output signals indicating a terminal current (160) flowing through the multiphase converter (100). The multiphase converter (100) further comprises a plurality of current sensors (134, 136, 138) configured to generate output signals indicating low side switch phase current of each phase leg. The multiphase converter (100) further comprises a low pass filter (142) for filtering out high frequency component of the low side switch current signal for each phase leg.