Adaptive Inverter Control for Power Conversion Loss Reduction
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Solution Overview
Problem
Conventional power conversion devices experience efficiency reduction due to switching losses in switching elements when converting DC to AC power.
Innovation Solution
A power conversion device that selects between two modes: a first mode with a high-frequency pulse signal sequence and a second mode with a lower frequency and fixed pulse width pulse signal sequence, reducing switching losses by optimizing the control of switching elements based on load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PWM control with high-frequency pulse signal sequence is used to convert DC to AC power, then the power conversion accuracy is improved, but switching losses increase causing efficiency reduction
Solution Approach 1:
The patent applies dynamics by making the switching frequency adaptive rather than fixed. The control device dynamically adjusts the switching frequency of the inverter based on real-time power output detection. When the power output is small, the switching frequency is reduced to minimize switching losses. When the power output is large, the switching frequency is increased to maintain power conversion accuracy. This dynamic adjustment resolves the contradiction between maintaining high conversion accuracy and reducing switching losses.
Solution Approach 2:
The patent changes the parameter of switching frequency based on operating conditions. By detecting the power output and adjusting the switching frequency accordingly, the system optimizes the balance between conversion accuracy and efficiency. At low power outputs, a lower switching frequency reduces switching losses while still maintaining adequate conversion performance. At high power outputs, a higher switching frequency ensures accurate power conversion. This parameter change strategy effectively resolves the technical contradiction.
Data Source
AI summary
When a load current is larger than a predetermined value, a control device of an uninterruptible power supply device controls an inverter by gate signals having a relatively high frequency and having controlled pulse widths, and when the load current is smaller than the predetermined value, the control device controls the inverter by the gate signals having a relatively low frequency and having fixed pulse widths. Therefore, when a load is a light load, switching losses occurring in IGBTs of the inverter can be decreased.