Power Converter Phase Transition Control
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Solution Overview
Problem
Existing power converters suffer from discontinuous phase transition current and high total harmonic distortion (THD) in output alternating-current power.
Innovation Solution
A power converter design incorporating a first, second, and third half-bridge circuit with a controller generating control signals by comparing a mixed sine wave with a high-frequency triangular carrier, utilizing a first inductor and capacitor for rectification and a second inductor and capacitor for filtering, to maintain continuous output current and reduce THD.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional control means are used in power converters, then the device complexity is reduced, but discontinuous phase transition current and high total harmonic distortion occur in the output alternating-current power
Solution Approach 1:
The control signal generation performs preliminary action by pre-mixing the third-order harmonic wave with the fundamental sine wave before comparison with the triangular carrier wave. This preliminary mixing action ensures that the PWM control signals inherently contain the necessary harmonic components to maintain continuous output current during phase transitions, preventing discontinuous phase transition current before it occurs.
Solution Approach 2:
The invention changes the parameter of the control signal by mixing in a third-order harmonic wave (150Hz when fundamental is 50Hz) with the fundamental sine wave. This parameter modification transforms the control approach from simple sine-wave PWM to harmonic-enhanced PWM, which maintains continuous current flow during phase transitions while also reducing total harmonic distortion in the output power.
2Manufacturing precision
If conventional PWM control is used, then the device complexity is minimized, but total harmonic distortion in output AC power increases
Solution Approach 1:
The control signal processing changes parameters by adding a third-order harmonic component to the fundamental sine wave used for PWM modulation. This parameter enhancement modifies the PWM control strategy to produce output power with reduced total harmonic distortion, improving power quality without requiring complex additional filtering or correction circuits.
Solution Approach 2:
The invention converts the potentially harmful effect of simple PWM control (which produces high THD) into a beneficial outcome by deliberately adding third-order harmonic mixing. This transforms the control signal processing from a source of distortion into a mechanism that actively reduces THD in the output power, turning a harmful effect into a benefit.
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 ensures continuous phase transition stability and reduces total harmonic distortion in output AC power, improving the quality of alternating-current power conversion.
Implementation Method 1
the control signal provided for the second half-bridge circuit or the third half-bridge circuit by the controller is generated by comparing a mixed sine wave with a high-frequency triangular carrier
Implementation Method 2
utilizing a first inductor and capacitor for rectification
Implementation Method 3
a second inductor and capacitor for filtering, to maintain continuous output current and reduce THD
Data Source
Figure 1
Figure 2
Figure 3(A)~3(C)
AI summary
A power converter (100) includes an AC power input line (11), an AC power output line (12), a neutral line (13), a first capacitor (14) connected to the AC power input line (11) and the neutral line (13), a first inductor (15) connected to the AC power input line (11), a first bus (16), a second bus (17), a second capacitor (18) connected to the first bus (16) and the second bus (17), a first half-bridge circuit (19) connected to the first bus (16), the second bus (17) and the first inductor (15), a second half-bridge circuit (20) connected in series with the first half-bridge circuit (19) and connected to the AC power output line (12), a third half-bridge circuit (21) connected in series with the first half-bridge circuit (19), a second inductor (22) connected to the third half-bridge circuit (21) and the neutral line (13), and a controller (23).