公开(公告)号：EP4439905A1

公开(公告)日：2024-10-02

申请号：EP23165724.8

申请日：2023-03-30

申请人： Hitachi Energy Ltd

发明人： Hasler, Jean-Philippe ,  Heydari, Rasool ,  Zhang, Hongyang ,  Danielsson, Christer

IPC分类号： H02J3/18 ,  H02J3/24 ,  H02J3/32 ,  H02J3/40 ,  H02M1/00

CPC分类号： H02J3/40 ,  H02J3/18 ,  H02J3/24 ,  H02J3/32 ,  H02M7/53803

摘要： There is disclosed herein a method (100) of determining a phase angle reference (θ) for synchronizing a grid-connected voltage-source converter, VSC, (5) with a power grid (4). The VSC comprising an energy storage (3). The method (100) comprising estimating (110) an angular deviation (dω) of a VSC reference from a fundamental grid frequency, based on an amount of energy (E) stored in the energy storage (3) and determining (120) the phase angle reference (θ) based on the angular deviation (dω). There is further disclosed a control unit (10) for performing the method and a grid-connected VSC comprising the control unit.

公开(公告)号：EP4459823A1

公开(公告)日：2024-11-06

申请号：EP23171854.5

申请日：2023-05-05

申请人： Hitachi Energy Ltd

发明人： Heydari, Rasool ,  Zhang, Hongyang ,  Hasler, Jean-Philippe ,  Mitra, Pinaki

IPC分类号： H02J3/24

摘要： The present disclosure provides a method and a control unit for controlling a power unit (14) connected at a connection point (20) to a power grid (16). The method comprises obtaining a power oscillation damping, POD, signal (POD) based on an oscillation in the power grid. The method further comprises determining a gain value (G) based on a difference between a first voltage measurement ( U 1 ) measured at the connection point and a first voltage reference ( U ref1 ), or an estimated short circuit ratio, SCR, of the power grid. The method further comprises adding the POD signal to an input signal (In2) of a power unit regulator (108) to obtain an intermediate reference signal (ref i ). The method further comprises determining a combined reference signal ( ref c ) based on the POD signal multiplied by the gain value (G,POD) and the intermediate reference signal, and operating the power unit using the determined combined reference signal to damp the oscillation in the grid.

公开(公告)号：EP4307834A1

公开(公告)日：2024-01-17

申请号：EP22184832.8

申请日：2022-07-13

申请人： Hitachi Energy Ltd

发明人： Hasler, Jean-Philippe ,  Christe, Alexandre

IPC分类号： H05B7/144

摘要： The present disclosure relates to a method of operating an electric arc furnace by means of an electric arc furnace operation system connectable with the electric arc furnace to form an electric arc furnace system, and to a corresponding system. The electric arc furnace operation system comprises a converter device connectable with the AC grid for supplying the electric arc furnace with electric power, an electrode controller controlling electrodes of the electric arc furnace, and a converter controller. The method includes the following operations:
- receiving, at the converter controller a reference impedance comprising a reference inductance and a reference resistance, a reference voltage, and an electrode voltage;
- determining, by means of the converter controller, a converter reference voltage on basis of at least the reference voltage, the reference impedance, the electrode voltage, and a physical inductance of the electric arc furnace system; and
- controlling the converter device to generate an output voltage on basis of the converter reference voltage.