Schneider Electric It Corporation

Stefano De Cesaris

Patrick Chambon

Daniel Rozand

According to various aspects and embodiments, a power device is provided. The power device includes an input configured to receive input power, an output configured to provide output power to a load, a power conversion circuit coupled to the input and configured with a first output line and a second output line, the first output line coupled to the output and configured to provide output current at the output, a capacitor coupled to a junction of the first output line and the output, and coupled to the second output line, and a controller coupled to the power conversion circuit. The controller is configured to receive a first current measurement for the first output line receive a first voltage measurement across the capacitor, and determine a load current based on the first current measurement and the first voltage measurement.

Inverter regulation

An uninterruptible power supply (UPS) system () comprises a plurality of UPS units (UPS-1, UPS-2) connected in parallel. Each UPS unit comprises a power converter () for supplying a share (i load 1, i_load_2) of a total load current (i_tot). The total load is shared automatically between UPS units of power ratings, in a proportionate manner. A controllerof each converter is arranged to establish real-time feedback control of a current supplied by the power converter. An exchange current (i_exch) for each converter represents an imbalance between an output current of the converter in question and output currents of the parallel converters. Exchange current sensing circuits of the parallel-connected UPS units are connected together. The controller steers the exchange current of each converter toward a value (i_exc_c) that is a non-zero proportion of a current (i_mut) sensed within the converter. Said non-zero proportion is calculated such that the exchange current will be steered towards a positive value in the case of a converter with higher than average nominal power rating and toward a negative value in the case of a converter with lower than average power rating.

Methods and apparatus for controlling power converters in parallel connection

The present disclosure relates to a controller, a circuit and method for controlling a power converter using pulse width modulation (PWM). At least one logic block () of the controller is configured to remove a command () which is configured to control the other power semiconductor switch () in a half-bridge () so that the other power semiconductor switch () remains in a non-conductive state while an antiparallel diode () allows an electric current () to pass in one direction, called the diode's forward direction, while blocking current in the opposite direction. In case the diode () is conducting instead of the other power semiconductor switch during the duration of the state of the command, the switching command () for the latter is omitted. The controller is further configured to modify the dead time interval (Tdead) between switching from the power semiconductor switch () to another power semiconductor switch () or vice versa in order to avoid a discontinuity in the transfer function ().

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Grenoble, France

Stefano De Cesaris