Fast valve power loss evaluation method for modular multi-level converter operating at high-frequency

Abstract

There is no common accepted way for calculating the valve power loss of modular multilevel converter (MMC). Valve power loss estimation based on analytical calculation is inaccurate to address the switching power loss and valve power loss estimation based on detailed electro-magnetic simulation is of low speed. To solve this problem, a method of valve power loss estimation based on the detailed equivalent simulation model of MMC is proposed. Results of valve power loss analysis of 201-level 500MW MMC operating at 50Hz~1000Hz are presented. It is seen that the valve power loss of a MMC increased by 12, 40 and 93 % under 200Hz, 500Hz and 1000Hz operating frequency. The article concludes that in a device with isolated inner AC system, MMC operating at higher frequency will be more competitive than typical 50Hz/60Hz MMC with moderate increase of operating power loss and significant reduction of the size of the AC components.

UUDAT based on the modular multilevel converter and diode bridges for high‐voltage DC application

“…The valve power loss estimation method of [10] which is based on simulations is adopted. The valve power loss of MMC is composed by the insulated‐gate bipolar transistor (IGBT) conduction losses, diode conduction losses, IGBT switching losses, diode recovery losses, and IGBT and diode cut‐off losses.…”

Interline dc power flow controller with fault current‐limiting capability

“…HVdc is developed from a two-terminal system to a direct current (dc) grid, which considerably increases the reliability of the power supply. However, the power flow in some transmission lines cannot be independently controlled using VSC [4][5][6]. This problem limits the transmission capacity of dc lines; in such cases, a dc power flow controller (DCPFC) may supplement the control capability of dc grids to achieve overall power flow control [7].…”

Power shift‐based optimal corrective control for bipolar multi‐terminal high‐voltage direct current grid

“…In recent years, as a promising VSC topology, the modular multi-level converter (MMC)-based MTDC grid offers an attractive solution to cope with the increased renewable energy source (RES) integration [11][12][13]. The MTDC grid with bipolar configuration takes the middle point between the positive and negative poles as the neutral bus, to which the ground electrode or dedicated metallic return is connected [14].…”