Circuits for DC energy stores

摘要

A dc energy store includes auxiliary systems operable in different modes, including self-supporting, island mode and normal modes. In the self-supporting mode a first controller uses a voltage demand signal indicative of desired ac voltage of an AC/DC power converter to control semiconductor power switching devices to achieve the desired level of ac voltage. The voltage demand signal is derived from comparing a voltage feedback signal and a second voltage demand signal preset to provide the desired ac voltage for the auxiliary systems. A second controller uses a current demand signal indicative of the desired dc link current to control the semiconductor power switching devices of a DC/DC power converter to achieve the desired level of dc link current. The current demand signal is derived from comparing a dc link voltage demand signal indicative of a desired dc link voltage and a dc link voltage feedback signal.

主权项

1. A dc energy store circuit comprising:
a dc energy store having auxiliary systems and dc terminals; an AC/DC power converter including a plurality of semiconductor power switching devices, the AC/DC power converter having ac terminals that are electrically connected to an ac supply network and dc terminals; a DC/DC power converter including a plurality of semiconductor power switching devices, the DC/DC power converter having first dc terminals electrically connected to the dc terminals of the AC/DC power converter by means of a dc link and second dc terminals electrically connected to the dc terminals of the dc energy store; a first controller for the AC/DC power converter; and a second controller for the DC/DC power converter; wherein, when the dc energy store is operating in a self-supporting mode in which power is supplied from the dc energy store to the auxiliary systems of the dc energy store:
the first controller uses a voltage demand signal indicative of desired ac voltage at the ac terminals of the AC/DC power converter to control the semiconductor power switching devices of the AC/DC power converter to achieve the desired level of ac voltage that corresponds to the voltage demand signal, the voltage demand signal being derived from a comparison of a voltage feedback signal and a second voltage demand signal that is preset to provide the desired ac voltage for the auxiliary systems of the dc energy store; andthe second controller uses a current demand signal indicative of desired dc link current to control the semiconductor power switching devices of the DC/DC power converter to achieve the desired level of dc link current that corresponds to the current demand signal, the current demand signal being derived from a comparison of a dc link voltage demand signal indicative of desired dc link voltage and a dc link voltage feedback signal.