Power Converter Boost-PWM Control Waveform Distortion
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Solution Overview
Problem
Conventional power converters face challenges in suppressing distortions of AC voltage and current waveforms during switching between boost and PWM controls, particularly in power generation systems using solar cells or fuel cells, where efficient power conversion and distortion minimization are crucial for optimal performance.
Innovation Solution
A power converter system incorporating a boost circuit, single-phase inverter, and a controller that generates voltage and current references to alternately perform PWM control on the single-phase inverter and boost control on the boost circuit, using wide-bandgap semiconductor switching elements and filters to minimize distortions, with a current controller that adjusts gate signals based on detected currents and voltages to optimize power conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If boost control and PWM control are alternately performed, then AC voltage output capability is improved, but waveform distortion increases during switching
Solution Approach 1:
The control apparatus uses feedback control to generate voltage references based on the difference between current output and current reference. The control apparatus detects output current and voltage, and adjusts gate signals dynamically to maintain waveform quality during switching between boost and PWM control modes.
Solution Approach 2:
The control apparatus generates voltage references in advance by calculating the difference between current reference and detected current. Gate signals are prepared and adjusted before switching occurs, ensuring smooth transitions and minimizing waveform distortion during the switching between control modes.
2Power
If boost circuit and single-phase inverter are used together, then voltage boosting capability is improved, but device complexity increases
Solution Approach 1:
The power converter integrates the boost circuit and single-phase inverter into a unified system where both circuits share common components and control architecture. The control apparatus manages both circuits through a single control unit that generates coordinated gate signals, reducing overall system complexity despite the combined functionality.
Solution Approach 2:
The control apparatus serves multiple functions by generating voltage references for both boost control and PWM control, detecting currents and voltages from both circuits, and producing gate signals for all switching elements. This multi-functional control unit simplifies the overall system architecture by consolidating control functions.
3Measurement precision
If current controller generates voltage reference based on current difference, then current control precision is improved, but control complexity increases
Solution Approach 1:
The control apparatus implements feedback control by continuously detecting the output current and comparing it with the current reference. The voltage reference is generated based on the difference between these values, creating a closed-loop control system that precisely controls current while using straightforward computational logic.
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 suppresses distortions in AC voltage and current waveforms, enhancing the efficiency and accuracy of power conversion, reducing the size of passive components, and maintaining high performance across varying load conditions.
Implementation Method 1
a boost circuit which boosts a voltage of a direct-current (DC) power supply
Implementation Method 2
a single-phase inverter which outputs an alternating-current (AC) voltage based on a voltage output from the boost circuit
Data Source
AI summary
A power converter according to embodiments includes a boost circuit, a single-phase inverter, a current controller, and a power conversion controller. The current controller generates a voltage reference based on a difference between current output from the single-phase inverter and a current reference. The power conversion controller controls the single-phase inverter to generate a first portion of the AC voltage, and controls the boost circuit to generate a second portion of the AC voltage. The first portion corresponds to the voltage reference of which an absolute value is smaller than the voltage of the DC power supply. The second portion corresponds to the voltage reference of which an absolute value is greater than the voltage of the DC power supply.