Control method for phase-locked loop-network construction type MMC converter station parallel power supply system

The invention discloses a control method for a phase-locked loop-network construction type MMC converter station power supply system. According to the control method, constant alternating-current voltage amplitude and active power are adopted, the MMC keeps synchronous with an alternating-current power grid through a phase-locked loop, a d-axis current reference value is adjusted according to q-axis voltage and an active current reference value in a q-axis voltage control link, and therefore the active power is adjusted to keep the angular frequency and the power angle stable; in the d-axis voltage control link, the q-axis current reference value is adjusted according to the d-axis voltage, so that the reactive power is adjusted to keep the PCC voltage stable. According to the invention, the frequency deviation is introduced to adjust the active current reference value, so that the MMC outputs the active power to respond to the frequency change, and the MMC has the primary frequency modulation characteristic;