Power supply device for sub-module controller of MMC converter
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.
1. A power supply apparatus for a sub-module controller of a MMC, comprising:
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 respectively connected in parallel with the N energy storage units in a form of a bridge and connected in series with each other;
a switching unit for switching any one of a first output terminal formed at a first end of n (1≤n<N) series-connected energy storage units, among the N energy storage units, and a second output terminal formed at a first end of m (n<m≤N) series-connected energy storage units; and
a DC/DC converter for converting a voltage, output through the first output terminal or the second output terminal depending on switching of the switching unit, into a lower voltage than the output voltage, and supplying the lower voltage to the sub-module controller.
2. The power supply apparatus of claim 1 , wherein the switching unit is configured to perform switching to make a connection to the second output terminal during a period from an initial operation to a preset first voltage, thus enabling a voltage stored in the m energy storage units to be supplied to the DC/DC converter, and to change switching to make a connection to the first output terminal during a period after the first voltage, thus enabling a voltage stored in the n energy storage units to be supplied to the DC/DC converter.
3. The power supply apparatus of claim 1 , wherein the bridge circuit unit comprises any one selected from a half-bridge circuit and a full-bridge circuit.
4. The power supply apparatus of claim 2 , wherein the bridge circuit unit comprises any one selected from a half-bridge circuit and a full-bridge circuit.