Ge Energy Power Conversion Technology Gmbh

Ge Energy Power Conversion Gmbh

Ge Energy Power Coversion Gmbh

Martin Geske

Allan David Crane

Roland Jakob

Nicolas Lapassat

Hendrik Gloes

Thomas Brueckner

Joerg Janning

Duro Basic

Robert Oesterle

Samir Soua

Siegfried Nowak

Jörg Janning

Piotr Szczupak

Gregory Reichhold

Varun Raghunath

Kowalsky Jens

Josef Lutz

Thomas Brückner

Christian Keller

A power converter system is described. The power converter system includes a power converter comprising at least one converter unit, each converter unit comprising a plurality of semiconductor devices, each semiconductor device including at least a controllable semiconductor switch. A local controller is associated with at least one converter unit and adapted to receive CD and MD from a main controller. In response to a detected fault condition of the power converter system, the local controller is adapted to use at least one of the one or more locally-stored values to determine an operating state of the power converter system, and to use the determined operating state to select a fault operating procedure to control each associated converter unit according to the selected fault operating procedure without using any CD from the main controller.

Fault current reduction for power converter systems

A power converter system is provided and includes a power converter having a first converter that includes at least a controllable semiconductor switch having a threshold voltage and a gate voltage for normal on-state conduction, DC terminals connected to a DC link, and AC terminals, a controller of the system supplies current to the first converter for short circuiting by controlling the switches to create a short circuit path through the converter that carries the current. At least one switch in a short circuit path is operated with modified on-state conduction to increase conduction losses by applying a modified gate voltage less than the gate voltage for normal on-state conduction, the modified gate voltage equals the threshold voltage plus x volts, where x ranges from 100 mV to 4 V, and when the converter is short-circuited, the DC link voltage is less than that during a normal switching operation.

Methods of starting power converter systems, and power converter systems

A power converter system is described. The system includes a power converter with a first converter including a plurality of semiconductor devices. Each semiconductor device includes at least a controllable semiconductor switch having a threshold voltage and a gate voltage for normal on-state conduction. The first converter has first and second DC terminals connected to a DC circuit, and a plurality of AC terminals. A controller is configured to supply current to the first converter (e.g., from an AC power source) and enable a short circuit state of the first converter by controlling semiconductor switches of the first converter to create at least one short circuit path through the first converter that carries the supplied current. At least one of the semiconductor switches in at least one of the short circuit paths is operated with modified on-state conduction in order to increase conduction losses. A gate driver applies to the semiconductor switch a modified gate voltage that is less than the gate voltage for normal on-state conduction.

A method of short-circuiting a faulty submodule for a voltage-source power converter is disclosed. The submodule is based on a full-bridge, asymmetric full-bridge or half-bridge circuit design having power semiconductor switches with anti-parallel freewheeling diodes and optionally non-controllable semiconductor valves. The methodincludes identifying a faulty semiconductor device and determining a failure mode selected from a short-circuit failure mode and an open circuit failure mode. The method further includes selecting a minimum number of power semiconductor switches suitable to provide a bypass path through the submodule depending on the identified faulty semiconductor device and the determined failure mode and driving the selected power semiconductor switches by a modified driving voltage compared to normal operation to cause them to break down in order to provide a durable, stable, low impedance short-circuit path between the AC voltage terminals of the submodule. A power converter comprising a series connection of such submodules and supporting the method of short-circuiting a faulty submodule is also disclosed.

Method of short-circuiting a faulty converter submodule and power converter supporting same

A modular multipoint power converter for converting an AC voltage to a DC voltage or vice versa, and a method of operating it are provided. The multipoint power converter has a converter branches, whereby two converter branches are connected to each other respectively to form a phase branch of the converter. Each converter branch has a plurality of similar submodules, each of which is formed from a half-bridge circuit with power semiconductor switches. The branch currents through the converter branches are controlled in operation by increasing the DC component of the DC current or the DC intermediate circular current such that a unipolar current flows through the converter branches. As a result, with the same plurality of submodules per converter branch, the transmissible power can be increased, the power semi-conductor elements can be better utilized, or the plurality of submodules can be reduced while the transmissible power remains the same.

Modular multipoint power converter and method of operating it

A dual submodule is created for a modular multilevel converter, whereby the dual submodule has two interconnected submodules, whereby each submodule has an asymmetrical half-bridge circuit with two parallel bridge branches, which are connected between a first and a second terminal connection of the submodule, whereby each bridge branch is formed from a series circuit of a power semiconductor switch, and a diode, whereby the power semiconductor switch is allocated to an antiparallel free-wheeling diode, and has a capacitor, which is connected in parallel with the asymmetrical half-bridge circuit between the first and the second terminal connections of the module. The submodules are connected to each other via their AC terminals to form the dual submodule. Further, a modular multilevel converter is created, comprising a number of such dual submodules in each of its converter branches.

Dual submodule for a modular multilevel converter and modular multilevel converter including the same

An inverter system is described. The inverter system includes a DC power source such as a plurality of photovoltaic (PV) panels, an inverter and a controller. The inverter includes a plurality of semiconductor devices (e.g., controllable semiconductor switches such as IGBTs and anti-parallel connected diodes) arranged in a suitable inverter topology. The inverter includes DC input terminals connected to the PV panels by means of a DC link and at least one AC output terminal. When starting the inverter, the controller is configured to enable a short circuit state of the inverter by controlling the semiconductor switches to create a short circuit between the DC input terminals such that the inverter carries a current substantially equal to the short circuit current of the PV panels. This short circuit current may be used to pre-heat the semiconductor devices of the inverter to reduce failure rates caused by cosmic radiation when the semiconductor devices subsequently experience high blocking voltages during normal operation of the inverter.

Methods of starting an inverter system, and inverter systems

A double submodule for a modular multilevel converter comprising a first and second submodule coupled to the first. Each submodule comprises an asymmetric H bridge circuit with two parallel bridges branches, connected between a first and a second direct voltage node of the submodule. Each bridge branch is formed by a series connection from a controllable power semiconductor switch and a diode. A storage capacitor is connected in parallel to the asymmetric H bridge circuit between the first and the second direct voltage node of the submodule. The first and the second submodule are interconnected in such a way that a power semiconductor switch or a diode is part of a bridge branch of the first submodule as well as part of a bridge branch of the second submodule. A modular multilevel converter, comprises a series connection of such double submodules in each of its converter branches, is also disclosed.

Low loss double submodule for a modular multi-level converter and modular multi-level converter having same

A method and a device for controlling a commutation process of a load current between two switching modules are disclosed that each have a MOSFET that can be controlled by a gate-source voltage, and an intrinsic-body inverse diode. To reduce oscillations in the down-commutation of the inverse diodes caused by parasitic circuit parameters, after switching off one of the switching modules, the gate-source control voltage applied to this switching module is temporarily switched off until being increased again the vicinity of the threshold voltage for switching on the MOSFET, before and while the other switching module is switched on, in order to commutate the current from the inverse diode of the one switching module to the MOSFET of the other switching module.

Method and control device for controlling a commutation process of a load current between switching modules

A switch module and a converter developed with the help of a switch module. The switch module presents two series connections comprising a power semi-conductor switch and a diode and. Parallel to the first series connection a first capacitor is connected. Between the first capacitor and the second series connection at least one intermediate connection is connected. This is designed as quadripole, whereby between both the output connections a second capacitor is connected. The first output connection is connected through a third power semi-conductor switch with the first input connection. The second output connection is connected with the cathode of a third diode, whose anode is connected with the second input connection of the intermediate circuit. With this switch module at least five voltage levels can be set up for an output voltage. For each additionally present intermediate circuit the number of the possible voltage levels increases by two.

Switch module and converter with at least one switch module

A device () for the on-demand commutation of an electrical current from a first line branch () to another, second line branch () is created, which has a number of power semiconductor switching elements (), which are arranged in series and/or parallel to one another in the second line branch (), and a control unit () for controlling the number of power semiconductor switching elements (). The control unit () is adapted to apply to each of the number of power semiconductor switching elements () an increased control voltage (VGE) whose level is above the maximum permissible control voltage specified for continuous operation, in order to switch on or maintain the conduction of the number of power semiconductor switching elements and to cause an increased current flow through it, whose current rating is at least double the nominal operating current. The control unit () is further adapted to switch off the number of power semiconductor switching elements after a respectively provided short switch-on duration by switching off the control voltage (VGE) again while they conduct an increased current flow. The device () can thus be designed for a higher power in operation, or, at a given operating power, the semiconductor area and size of the device () can be reduced.

Device for temporarily taking over electrical current from an energy transfer or distribution device, when needed

A method and a device for controlling a voltage-controlled power semiconductor switch that can be switched off again, which has a first and a second connection and a control connection and which is conductive in the switched on state between the first and the second connection is provided. Firstly, a first control voltage comprising a first value is applied to the control connection to switch on the power semiconductor switch. Subsequently, conditions are detected, which indicate the progress of the switch-on procedure of the power semiconductor switch. As soon as conditions are detected, which are indicative of the fact that the switch-on procedure is deemed to be complete, a second control voltage comprising a second value higher than the first value is applied to the control connection to operate the power semiconductor switch in the conductive state with a higher control voltage to reduce its conduction losses.

Method and device for controlling a voltage-controlled power semiconductor switch that can be switched off again

A short-circuit device and a protection method for a submodule for a power converter are disclosed. The submodule includes a bridge circuit having at least one power semiconductor branch extending between a first and a second DC voltage node and at least one controllable power semiconductor switch disposed therein to which a freewheeling diode is connected in anti-parallel, and a capacitor connected in parallel to the bridge circuit. The short-circuit device has at least one selected of the freewheeling diodes anti-parallel to the power semiconductor switches of the bridge circuit, wherein the at least one selected freewheeling diode is manufactured in press pack design and rated such that, when a fault occurs in the submodule, the at least one selected freewheeling diode breaks down due to the fault conditions and provides a durable, stable, low-impedance short circuit path between a first and a second AC voltage connection of the submodule.

Converter submodule with short-circuit device and power converter having same

A thyristor circuit comprising at least one series circuit in which two or more thyristors are connected in series. Each thyristor is parallel-connected to an RC member. A control device can energize the thyristors individually and independently of each other by a control signal, so that each thyristor can be individually switched into its conducting condition. During a test sequence, the thyristors are switched successively into their conducting condition, wherein, in a series circuit and/or in the thyristor circuit, respectively only one thyristor is in its conducting condition. While a thyristor is conducting, the capacitor of the associate RC member discharges and produces a thyristor current. As a result, the conducting condition is maintained until the thyristor current falls below the holding current. The control device can use the thyristor voltage and/or the thyristor current to evaluate the function or the switching behavior of the thyristor.

Circuit arrangement with a thyristor circuit, as well as a method for testing the thyristor circuit

A circuit arrangement connected to an electrical circuit including a transformer with primary winding connected to the electric power grid and secondary winding connected to a power converter with a capacitor, the circuit arrangement has a primary winding coupled to the auxiliary winding, which is connected to a switching device.

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Berlin, Germany

Martin Geske