Inverter Switch Power Loss Measurement via Pre-stored Voltage
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Solution Overview
Problem
Existing inverters in wind power plants face challenges in accurately determining power losses in switches, which are essential for preventing thermal overload and extending the lifespan of semiconductor switches, due to limitations in measuring collector-emitter voltage and accounting for environmental factors like ambient temperature.
Innovation Solution
A method and device that detect instantaneous physical variables of switches, correlate these values with data from memory, and process them to output precise power loss calculations, allowing for real-time monitoring and statistical evaluation, and can be integrated into the inverter or wind energy installation control to adjust operational parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If collector-emitter voltage is measured to determine power loss, then power loss can be calculated, but measurement precision deteriorates due to the full intermediate circuit voltage being present in the blocked state
Solution Approach 1:
The patent applies preliminary action by pre-storing collector-emitter voltage values corresponding to different current values in a memory device before actual operation. During operation, the system only needs to retrieve the pre-stored voltage value based on the measured current, avoiding the need to measure the difficult collector-emitter voltage directly. This resolves the measurement precision problem while enabling power loss calculation.
Solution Approach 2:
The patent uses current measurement as an intermediary to indirectly obtain collector-emitter voltage information. Instead of directly measuring the difficult collector-emitter voltage (especially in blocked state with full intermediate circuit voltage), the system measures the easier current and uses it to retrieve the corresponding voltage from pre-stored data, thereby calculating power loss accurately.
2Reliability
If switch temperature is monitored to control the inverter, then thermal overload can be prevented, but the actual power loss cannot be precisely determined due to environmental factors
Solution Approach 1:
The patent implements feedback by continuously measuring the actual current through the switch and retrieving the corresponding collector-emitter voltage from pre-stored data to calculate actual power loss. This actual power loss measurement provides feedback that reflects environmental factors like ambient temperature, enabling more accurate thermal management and switch replacement decisions compared to fixed mathematical forecasts.
Data Source
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AI summary
The method involves detecting an instantaneous value of a physical parameter of an electronic switch (12) and retrieving a value correlated with the instantaneous value from a memory. The values are processed with one another in a preset manner by a processing device (18), and the processed result is transmitted by a transmitting device. Measured values and the processed result are stored in another memory. Independent claims are also included for the following: (1) a device for determining thermal power loss of an electronic switch, comprising a memory (2) a method for controlling an inverter (3) an inverter (4) a wind turbine comprising an inverter (5) a method for controlling a wind turbine.