DC-DC Power Converter Phase Current Balancing
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Solution Overview
Problem
Multi-phase DC-DC power converters face challenges in current balancing, which leads to increased capacitor size and component stress due to unbalanced electric power load among phases, necessitating a method to reduce current ripple and evenly distribute power.
Innovation Solution
A DC-DC power converter system comprising multiple switched inductance circuits, current sensors, and a controller that determines and executes phase-shifted activation commands to balance currents across phases, using a shared current regulator to adjust activation commands based on average measured currents, thereby reducing capacitor size and minimizing component stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multi-phase DC-DC power converters are used to reduce current ripple, then the capacitor size can be reduced, but current balancing among phases becomes difficult to achieve
Solution Approach 1:
The patent implements a feedback mechanism where the controller continuously monitors the current output of each phase and adjusts the activation commands accordingly. The controller determines whether each phase exceeded its current limit and modifies the PWM duty cycle in subsequent cycles to prevent recurrence, creating a closed-loop control system that automatically balances current distribution among phases.
Solution Approach 2:
The patent employs dynamic adjustment of PWM duty cycles for each phase based on real-time current measurements. Instead of using fixed duty cycles, the controller dynamically modifies the activation commands for each switched inductance circuit, allowing the system to adapt to changing load conditions and maintain current balance across all phases.
2Stability of the object's composition
If phase-shifted activation commands are used to balance currents, then current distribution improves, but control complexity increases
Solution Approach 1:
The patent divides the control of each phase into independent segments, where each phase has its own current monitoring and control logic. The controller evaluates each phase separately, determining individual duty cycle adjustments based on each phase's current status, allowing for granular control that simplifies the overall balancing mechanism while maintaining current distribution stability.
Solution Approach 2:
The patent implements preliminary action by predicting current limits and adjusting PWM duty cycles before current imbalance occurs. The controller uses historical current data and predetermined current limits to proactively modify activation commands, preventing current imbalance rather than reacting to it, which simplifies the control mechanism by avoiding complex real-time correction algorithms.
3Quantity of substance
If current balancing is achieved through complex control algorithms, then current ripple is reduced, but processing time increases
Solution Approach 1:
The patent applies partial action by focusing control efforts only on phases that exceed their current limits, rather than continuously adjusting all phases. The controller identifies specific phases requiring correction and applies duty cycle modifications only to those phases, reducing processing time while still achieving effective current ripple reduction through targeted control actions.
Data Source
AI summary
A DC-DC power converter including switched inductance circuits arranged in parallel is described. Operation includes determining a commanded current and activation commands for the switched inductance circuits based upon the commanded current. This includes executing the activation commands and monitoring current in the switched inductance circuits. An average measured current is determined for each of the switched inductance circuits, and a modified activation command is determined for each of the switched inductance circuits based upon the average measured current. A time portion of the modified activation command that exceeds an end time point of a subsequent time period is determined, and the modified activation commands for the switched inductance circuits are executed, including forward-shifting that time portion of the modified activation command for each of the switched inductance circuits that exceeds the end time point.