Series Semiconductor Switch Drivers With Paired Power Supply
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Solution Overview
Problem
The energy supply to drivers of semiconductor switches in series-connected power converter modules is challenging due to high voltage fluctuations and inefficiencies when using capacitors, particularly when multiple capacitors are connected in series.
Innovation Solution
A circuit arrangement where pairs of semiconductor switches are supplied with energy from a switching power supply using the voltage between the load connections of a first semiconductor switch, with each pair having a driver and a freewheeling diode for overvoltage protection, and the switches are arranged in a series connection with a partial series circuit to minimize potential differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If energy is supplied from a capacitor connected to a single semiconductor switch, then the driver receives energy, but voltage fluctuations occur and the solution is not scalable to series connections
Solution Approach 1:
The series connection of semiconductor switches is divided into pairs, with each pair having a dedicated switching power supply. This segmentation allows the system to scale to any even number of switches while maintaining stable energy supply, as each power supply handles only two switches rather than the entire series string.
Solution Approach 2:
A switching power supply is introduced as an intermediary between the high-voltage series connection and the low-voltage driver circuits. This intermediary converts the voltage from one switch's load terminals into a stable supply for two drivers, isolating the drivers from voltage fluctuations in the series string.
2Reliability
If energy is extracted from a capacitor circuit for the entire series connection, then all drivers can be supplied, but the high voltage causes difficulties and risks
Solution Approach 1:
Instead of using a single capacitor circuit for the entire series connection, the system uses multiple switching power supplies, each handling only two switches. This segmentation distributes the high voltage exposure across multiple isolated units, reducing the risk associated with any single point of failure.
Solution Approach 2:
Each switching power supply uses the voltage from one of its own switches (the first switch in the pair) to supply energy to both drivers in the pair. This self-service approach eliminates the need to extract energy from the entire series string, isolating each power supply from the full high voltage of the series connection.
3Ease of operation
If voltage is taken from one capacitor among several in series, then drivers can be supplied, but voltage distribution fluctuations between capacitors cause problems
Solution Approach 1:
The switching power supply acts as an intermediary that takes the potentially fluctuating voltage from one capacitor and converts it into a stable supply for two drivers. This conversion process isolates the drivers from voltage distribution fluctuations in the series capacitor string.
Solution Approach 2:
The harmful effect of voltage fluctuations is extracted and isolated within the switching power supply circuitry. The power supply takes in the fluctuating voltage from one capacitor, processes it internally, and outputs a stable voltage to the drivers, effectively removing the instability from the driver supply.
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
This solution ensures stable and efficient energy supply to drivers of semiconductor switches in series connections, reducing voltage fluctuations and overvoltage risks while maintaining a compact and efficient design.
Implementation Method 1
a switching power supply for each two semiconductor switches forming a pair of switches is supplied with energy from an electrical voltage between the two load connections of a first semiconductor switch of the switch pair
Implementation Method 2
a freewheeling diode is connected in parallel to each semiconductor switch. This protects the semiconductor switches from overvoltages when their switching state changes
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a circuit arrangement (3) comprising an even number of semiconductor switches (5, 6), which are connected in series and comprise in each case two load terminals (7, 8) and a control terminal (9) and are associated with one another in pairs. The circuit arrangement (3) also comprises, for each semiconductor switch (5, 6), a driver (11) for actuating the semiconductor switch (5, 6) via the control terminal (9) thereof and, for every two semiconductor switches (5, 6) that form a switch pair (15), comprises a switching power supply (17) which is supplied with energy from an electrical voltage between the two load terminals (7, 8) of a first semiconductor switch (5) of the switch pair (15) and supplies both the driver (11) of the first semiconductor switch (5) and the driver (11) of the second semiconductor switch (6) of the switch pair (15) with energy.