MMC Sub-Module Controller Power Supply Bridge Circuit
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Solution Overview
Problem
Conventional power supply apparatuses for sub-module controllers in MMCs connected to HVDC systems experience unnecessary loss due to the use of resistors for voltage division, which is inefficient.
Innovation Solution
A power supply apparatus utilizing a bridge circuit unit with energy storage units and power semiconductor devices connected in series, along with a switching unit and a DC/DC converter to convert high voltage into low voltage, minimizing losses by selectively switching between different output terminals based on voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If resistor-based voltage division is used to convert high voltage to low voltage, then voltage conversion is achieved, but unnecessary energy loss occurs
Solution Approach 1:
The patent changes the operating parameters of the power supply device by using a bridge circuit configuration with controllable switches that dynamically adjust the voltage conversion ratio. Instead of fixed resistor values, the system varies the effective impedance and voltage division ratio through switching operations, achieving efficient voltage conversion across different operating conditions without resistive losses.
Solution Approach 2:
The invention introduces dynamic control through controllable switches in the bridge circuit that can change the circuit configuration in real-time. This allows the voltage conversion ratio to be dynamically adjusted based on the input voltage level and power requirements, enabling the system to operate efficiently across a wide range of conditions rather than being fixed like resistor-based solutions.
2Power
If multiple series-connected resistors are used for voltage division, then voltage conversion is achieved, but power loss increases
Solution Approach 1:
The patent replaces the passive mechanical/resistive voltage division system with an active electronic switching system. Instead of using resistors that continuously dissipate power, the invention uses controllable switches that redirect current flow through different circuit paths, achieving voltage conversion without continuous resistive losses.
Solution Approach 2:
The bridge circuit operates by periodically switching between different configurations, creating a pulsed voltage conversion mechanism. The controllable switches open and close in specific sequences, transferring energy in discrete packets rather than continuous dissipation, which significantly reduces average power loss while maintaining effective voltage conversion.
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 minimizes losses and achieves higher efficiency compared to conventional resistor-based voltage division methods, providing stable and efficient power supply to sub-module controllers.
Implementation Method 1
a bridge circuit unit including N (N≥2, integer) energy storage units for storing a DC voltage in a sub-module of the MMC
Implementation Method 2
a DC/DC converter to convert the high voltage into a low voltage required for the sub-module controller
Data Source
Figure 1
Figure 2
Figure 3a
AI summary
Disclosed herein is a power supply apparatus for a sub-module controller of a Modular Multilevel Converter (MMC), which supplies driving power to the sub-module controller of an MMC connected to a High Voltage Direct Current (HVDC) system. The power supply apparatus includes a bridge circuit unit including N (N≥2, integer) energy storage units for storing a DC voltage in series-connected sub-modules in the MMC and multiple power semiconductor devices connected in parallel with the N energy storage units in a form of a bridge; and a DC/DC converter for converting a voltage output from output terminals formed between both ends of n (1≤n<N) series-connected energy storage units, among the N energy storage units, into a low voltage and supplying the low voltage to the sub-module controller.