Power Converter Circuit Eliminates Dead Time Distortion
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Solution Overview
Problem
In voltage-fed three-phase PWM inverters, the dead time required to prevent concurrent switching of upper and lower arm devices leads to significant distortion of the output voltage waveform.
Innovation Solution
A power converter circuit configuration that includes specific switching devices, diodes, coils, and capacitors, allowing for controlled charging and discharging of capacitors to maintain sinusoidal output voltages without dead time, using IGBTs and diodes in series configurations to prevent through currents and maintain current connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dead time is provided to prevent concurrent switching of upper and lower arm devices, then device safety is improved, but output voltage waveform distortion increases
Solution Approach 1:
The patent introduces a third switching device as an intermediary element between the upper and lower arm switching devices. This third device acts as a mediator that allows controlled concurrent switching of the upper and lower arm devices while preventing direct through-current paths. The intermediary device enables the system to achieve both device safety and reduced waveform distortion by managing the switching transitions in a controlled manner.
2Reliability
If dead time is extended to ensure safe switching transitions, then device protection is improved, but productivity decreases
Solution Approach 1:
The patent enables continuous power delivery through the introduction of the third switching device and associated capacitor, which maintains current flow continuity during switching transitions. This allows the inverter to operate without traditional dead time gaps, maintaining productive operation while ensuring safe switching transitions. The useful action of power conversion continues uninterrupted, improving both reliability and productivity simultaneously.
3Device complexity
If conventional switching configuration is used, then device simplicity is maintained, but output voltage waveform distortion increases
Solution Approach 1:
The patent segments the conventional two-level switching structure into a three-level configuration by introducing a third switching device and associated components. This segmentation allows independent control of switching transitions, enabling precise management of current paths during switching events. The segmented structure reduces waveform distortion by providing additional control degrees of freedom while maintaining manageable device complexity through modular architecture.
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 solution effectively suppresses waveform distortion and ensures smooth current changes during switching operations, maintaining sinusoidal output voltages and preventing device breakdowns, even with concurrent IGBT switching.
Implementation Method 1
a first coil and a second coil connected in series between a first node, at which the first switching device and the first diode are connected, and a second node, at which the second switching device and the second diode are connected
Implementation Method 2
a first capacitor connected between a third node, at which the first coil and the second coil are connected, and the third line
Data Source
AI summary
A power converter circuit includes: a first switching device connected to a first line on a positive voltage side; a first diode having a cathode connected to the first switching device and an anode connected to a second line on a negative voltage side; a second diode having a cathode connected to the first line; a second switching device connected to an anode of the second diode and the second line; a first coil and a second coil connected in series between a first node, at which the first switching device and the first diode are connected, and a second node, at which the second switching device and the second diode are connected; and a first capacitor connected between a third node, at which the first coil and the second coil are connected, and a third line.