Voltage Compensation for Converter Dead Time
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Solution Overview
Problem
Grid-connected converters experience output voltage loss and waveform distortion due to the delay time in switching semiconductor switch components, leading to potential short-circuits and weakened performance.
Innovation Solution
A voltage compensating method that detects current values during dead time periods, calculates voltage compensation values based on these currents, and adjusts switching times for the switch modules to minimize voltage loss and distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dead time period is set to prevent simultaneous switching on of switch modules, then short-circuit prevention is achieved, but output voltage loss and waveform distortion occur
Solution Approach 1:
The patent adjusts switching parameters dynamically by calculating compensation values based on dead time duration and inductor current. The compensation value is added to the PWM wave to offset voltage loss during dead time periods, thereby maintaining output voltage accuracy while preserving the protective dead time function.
Solution Approach 2:
The patent implements a feedback mechanism where the actual inductor current during dead time is detected and used to calculate compensation values. This closed-loop approach continuously adjusts the PWM wave to compensate for voltage distortion, ensuring output voltage waveform accuracy is maintained despite the presence of dead time periods.
2Power
If semiconductor switch components are used for bipolar sinusoidal pulse width modulation, then DC power is converted to AC power, but delay time in switching causes potential short-circuits
Solution Approach 1:
The patent applies preliminary action by pre-calculating compensation values based on the known dead time duration and inductor current characteristics before the actual switching occurs. This allows the system to proactively offset the inevitable voltage loss and timing delays, preventing short-circuits while maintaining power conversion functionality.
Solution Approach 2:
The patent implements preliminary anti-action by adding compensation values to the PWM wave in advance to counteract the harmful effects of switching delays. This preemptive compensation prevents the voltage distortion and potential short-circuits that would otherwise result from the inherent delay time in semiconductor switch components.
3Reliability
If dead time period is extended to buffer delay time, then switching safety is improved, but voltage compensation requirement increases
Solution Approach 1:
The patent uses feedback by detecting the actual inductor current during dead time periods and using this information to calculate precise compensation values. This ensures that the compensation is optimized for the actual operating conditions, minimizing energy loss while maintaining the extended dead time safety buffer.
Solution Approach 2:
The patent dynamically adjusts compensation parameters based on the extended dead time duration and actual current conditions. By changing the compensation value according to the specific dead time period and load conditions, the system minimizes voltage loss and energy waste while preserving the safety benefits of extended dead time.
Data Source
AI summary
A voltage compensating method is applied to a converter for converting a DC voltage into an AC voltage. The converter includes a first switch module, a second switch module, and an inductor. In a first dead time period, detect a first current value related to the inductor. According to the first current value, calculate a second current value and a third current value related to the inductor. According to polarities of the first, second and third current values, determine an output mode of the converter indicating a voltage compensation model after the first dead time period. According to the voltage compensation model, the first current value, and the second current value or the third current value, calculate a voltage compensation value. In a second dead time period, adjust a switching time for the first switch module and the second switch module according to the voltage compensation value.