Inverter Gate Voltage Control for Parallel Switch Current Balance
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Solution Overview
Problem
Current imbalance among parallel-connected switching elements in inverters leads to reduced voltage output and reliability due to varying resistance components caused by assembly deviations and hardware complexity, resulting in inefficient power distribution.
Innovation Solution
A method and device for controlling inverters by detecting current imbalances and adjusting duty cycles of switching mode power supplies (SMPSs) to equalize current flow through parallel-connected switching elements, using a controller and SMPSs to manage gate voltages based on current differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a plurality of switching elements are connected in parallel to increase output voltage, then the power performance is improved, but current imbalance occurs due to varying resistance components
Solution Approach 1:
The patent applies local quality by adjusting the gate voltage of each switching element individually based on its specific current characteristics. The controller detects current through each switching element and applies different gate voltages to compensate for resistance variations, ensuring each element operates with optimal local conditions rather than uniform control.
Solution Approach 2:
The patent implements feedback control by continuously detecting the current flowing through each switching element and using this information to adjust the gate voltage dynamically. The controller receives current detection signals and modifies the driving signals accordingly, creating a closed-loop system that maintains current balance despite resistance variations.
2Power
If parallel connection of switching elements is used to increase power output, then the voltage output is improved, but the device complexity increases due to multiple SMPSs and control circuits
Solution Approach 1:
The patent merges multiple SMPS units into a coordinated system where each SMPS corresponds to a switching element. Rather than treating them as separate independent systems, the controller integrates their operation by dynamically adjusting duty cycles based on real-time current detection, combining multiple control functions into a unified management structure.
Solution Approach 2:
The patent applies dynamics by making the gate voltage and duty cycle adjustable rather than fixed. The controller dynamically modifies the driving parameters of each SMPS based on detected current conditions, allowing the system to adapt its complexity level according to operating conditions rather than maintaining static high complexity.
3Reliability
If duty cycle of an SMPS is reduced to decrease current through a switching element, then the current imbalance is resolved, but the gate voltage control precision must be increased
Solution Approach 1:
The patent changes the control parameter from fixed gate voltage to dynamically adjustable gate voltage based on duty cycle. By modifying the duty cycle parameter of each SMPS, the system achieves precise control over the average current through each switching element, allowing fine-tuned adjustment without requiring extremely high instantaneous voltage precision.
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
Resolves current imbalance, reduces temperature rise, improves output performance, and enhances reliability by equalizing current distribution, thereby increasing the efficiency and reliability of the inverter.
Implementation Method 1
the resistance component between paths according to the parallel connection of a plurality of switching elements varies due to parasitic components
Data Source
AI summary
A device for controlling an inverter controls the inverter including at least one switching module including a plurality of switching elements connected in parallel, detects current flowing through the plurality of switching elements, determines duty cycles of a plurality of switching mode power supplies (SMPSs) corresponding to the plurality of switching elements based on the detected plurality of currents, and controls a plurality of currents flowing through the plurality of switching elements according to the duty cycles of the plurality of SMPSs.