Abstract: A method and apparatus are provided for balancing currents of two or more parallel-connected power semiconductor switches during an on-state of the switches. A control terminal of each switch is driven by a driver unit. The method includes determining ratios between the currents through the switches. For each switch, the method includes controlling the voltage at the control terminal on the basis of the ratios by controlling a level of a supply voltage of the driver unit of the switch, and after a turn-on commutation transient, modulating the output of the driver unit. The duty cycle of the modulation is controlled to minimize the time required for the transition of the voltage at the control terminal from the one voltage level to another.

Abstract: In a method for generating with a modular multilevel power converter (M2C) having a plurality of sub-modules a frequency-variable output voltage, the sub-modules are switched on and off to generate from an input voltage discrete voltage steps approximating an approximately sinusoidal alternating output voltage having a first angular frequency located between a zero frequency and a second angular frequency, and the input voltage is controlled or regulated as a function of the first angular frequency so as to be located between a lower angular frequency, which is equal to or greater than the zero frequency, and a third angular frequency, such that the input voltage increases with increasing first angular frequency, thereby reducing capacitor complexity in the power converter.

Abstract: A method for operating a multi-phase modular power inverter having DC input terminals and AC phase voltage output terminals connected to a load, phase modules connected between the DC input terminals, with each phase module composed of valve arms connected in series at a connection point forming an AC phase voltage output terminal which is connected to a load, each valve arm having a plurality of power inverter cells with turn-off semiconductor switches and a choke connected in series, includes controlling, with a control device, the turn-off semiconductor switches of each power inverter cell as a function of a plurality of setpoint values, wherein the setpoint values are generated such that a time-averaged energy value stored in a capacitor of a corresponding power inverter cells is predetermined by an operating point of the load and-or an operating mode of the modular multi-level power inverter.

Abstract: Unique systems, methods, techniques and apparatuses of a reverse-conducting IGBT (RC-IGBT) are disclosed. One exemplary embodiment is a circuit comprising a series connection of controllable switch components where at least one of the controllable switch components is an RC-IGBT. The circuit is operated by applying a pre-trigger pulse to the gate electrode of the RC-IGBT during reverse conduction of the RC-IGBT at a first time instant, the pre-trigger pulse corresponding to a turn-on gate pulse. Next, a turn-on gate pulse is applied at a second time instant to the other controllable switch component of the series connection for controlling the other controllable switch component to a conductive state such that the pre-trigger pulse and the turn-on gate pulse overlap, and ending the pre-trigger pulse after a delay time at the third time instant. The delay time is the time period when the turn-on gate pulse and the pre-trigger pulse overlap.

Abstract: A method and an arrangement of controlling a reverse-conducting IGBT (RC-IGBT) component in a circuit comprising a series connection of controllable switch components where at least one of the controllable switch components is an RC-IGBT and the other component is to be controlled to a conductive state. The method comprising applying a pre-trigger pulse to the gate electrode of the RC-IGBT during reverse conduction of the RC-IGBT at a first time instant (t1), the pre-trigger pulse corresponding to a turn-on gate pulse, applying a turn-on gate pulse at a second time instant (t2) to the other controllable switch component of the series connection for controlling the other controllable switch component to a conductive state such that the pre-trigger pulse and the turn-on gate pulse overlap, and ending the pre-trigger pulse after a delay time at the third time instant (t3), the delay time being the time period when the turn-on gate pulse and the pre-trigger pulse overlap.

Abstract: In a method for generating with a modular multilevel power converter (M2C) having a plurality of sub-modules a frequency-variable output voltage, the sub-modules are switched on and off to generate from an input voltage discrete voltage steps approximating an approximately sinusoidal alternating output voltage having a first angular frequency located between a zero frequency and a second angular frequency, and the input voltage is controlled or regulated as a function of the first angular frequency so as to be located between a lower angular frequency, which is equal to or greater than the zero frequency, and a third angular frequency, such that the input voltage increases with increasing first angular frequency, thereby reducing capacitor complexity in the power converter.

Abstract: A method and apparatus are provided for balancing currents of two or more parallel-connected power semiconductor switches during an on-state of the switches. A control terminal of each switch is driven by a driver unit. The method includes determining ratios between the currents through the switches. For each switch, the method includes controlling the voltage at the control terminal on the basis of the ratios by controlling a level of a supply voltage of the driver unit of the switch, and after a turn-on commutation transient, modulating the output of the driver unit. The duty cycle of the modulation is controlled to minimize the time required for the transition of the voltage at the control terminal from the one voltage level to another.

Abstract: A method and apparatus are provided for a power semiconductor switch. A current through the switch is responsive to a control terminal voltage at a control terminal of the switch, and the control terminal voltage is driven by a driver unit. The method includes measuring or estimating the current based on a bond voltage of the switch, detecting a short circuit by comparing the measured or estimated current to a short circuit current limit, controlling an on-state voltage level of the control terminal voltage based on the comparison to limit the current through the switch during the short circuit, and controlling the control terminal voltage to an off-state voltage level to turn the switch off. The on-state voltage level voltage is controlled by pulse-width modulating the output of the driver unit. A switching frequency of the modulation is at least the cut-off frequency of low-pass characteristics of the control terminal.

Abstract: A method for operating a multi-phase modular power inverter having DC input terminals and AC phase voltage output terminals connected to a load, phase modules connected between the DC input terminals, with each phase module composed of valve arms connected in series at a connection point forming an AC phase voltage output terminal which is connected to a load, each valve arm having a plurality of power inverter cells with turn-off semiconductor switches and a choke connected in series, includes controlling, with a control device, the turn-off semiconductor switches of each power inverter cell as a function of a plurality of setpoint values, wherein the setpoint values are generated such that a time-averaged energy value stored in a capacitor of a corresponding power inverter cells is predetermined by an operating point of the load and-or an operating mode of the modular multi-level power inverter.

Abstract: A method and an arrangement are provided for balancing the switching transient behavior of parallel connected power semiconductor components. The method includes providing a switch signal to the parallel connected power semiconductor components for changing the state of the components, forming control signals for each of the parallel connected components from the switch signal, and determining, during the change of state of the power semiconductor component, the voltage induced to an inductance in the main current path of the component in each of the parallel connected components. The method also includes comparing each of the induced voltages with a predetermined threshold voltage, measuring time differences between the time instants at which the induced voltages crosses the threshold voltage, and modifying one or more of the control signals on the basis of the measured time differences in the respective following state change for balancing the switching transient behavior.

Abstract: A method and an arrangement are provided for balancing the switching transient behavior of parallel connected power semiconductor components. The method includes providing a switch signal to the parallel connected power semiconductor components for changing the state of the components, forming control signals for each of the parallel connected components from the switch signal, and determining, during the change of state of the power semiconductor component, the voltage induced to an inductance in the main current path of the component in each of the parallel connected components. The method also includes comparing each of the induced voltages with a predetermined threshold voltage, measuring time differences between the time instants at which the induced voltages crosses the threshold voltage, and modifying one or more of the control signals on the basis of the measured time differences in the respective following state change for balancing the switching transient behavior.

Abstract: The electronic generator power PG is compared with a predetermined power range in order to set the torque of the synchronous generator of a wind energy installation. A choice between two control modes is made on the basis of the comparison, and a reference power PG* is determined that corresponds to the maximum power production. This reference power PG* is compared with the electrical generator power PG, and a reference current IE* that is proportional to the power difference is produced and supplied to the field controller. The field controller draws power in a controlled manner from the capacitive DC voltage intermediate circuit as a function of the reference current IE*, and supplies this power to the excitation field. Changing the excitation field results in a change in the torque and hence in the rotational speed of the synchronous generator, which enables the two power values to be matched.

Abstract: An open-loop and closed-loop control method is proposed for a single-phase or polyphase three-point converter which is connected to a DC voltage intermediate circuit, having two series-connected main switches/inverse diodes between each DC voltage connection and each load connection. The common junction point of the two inner main switches forms the load connection. An active clamped switch with an inverse diode is connected between each common junction point of an inner main switch and an outer main switch and the center tap of the DC voltage intermediate circuit. As a result of which, two possible paths are formed for connecting a load connection to the center tap. Irrespective of the direction of the load current, at least one of the two active clamped switches (T5, T6) is connected to the center tap together with at least one inner main switch for connection of a load connection.

Abstract: An open-loop and closed-loop control method is proposed for a single-phase or polyphase three-point converter which is connected to a DC voltage intermediate circuit, having two series-connected main switches/inverse diodes between each DC voltage connection and each load connection. The common junction point of the two inner main switches forms the load connection. An active clamped switch with an inverse diode is connected between each common junction point of an inner main switch and an outer main switch and the center tap of the DC voltage intermediate circuit. As a result of which, two possible paths are formed for connecting a load connection to the center tap. Irrespective of the direction of the load current, at least one of the two active clamped switches (T5, T6) is connected to the center tap together with at least one inner main switch for connection of a load connection.

Abstract: A three-point converter with NPC diodes disposed between bridge halves and a center tap of an intermediate circuit is proposed. A decoupling network is provided for the upper bridge half, a first input of which decoupling network is connected to a positive pole of the intermediate circuit and a first output of the decoupling network is connected to a positive pole of the three-point converter. Furthermore, provision is made of a further decoupling network for the lower bridge half, a first input of the further decoupling network is connected to a negative pole of the intermediate circuit and a first output of the further decoupling network is connected to a negative pole of the three-point converter. The remaining inputs of both of the decoupling networks are connected to the center tap of the intermediate circuit. The remaining outputs of both of the decoupling networks are connected via the NPC diodes to the upper and lower bridge halves.

Abstract: A three-phase matrix converter for converting AC voltages of predetermined amplitude and frequency into AC voltages of any amplitude and frequency and a method for operating the same, include four-segment switches as main switches which are combined into three switch groups. A resonance capacitance is connected in parallel with each main switch, or an output capacitance of power semiconductors of the main switches acts as a resonance capacitance. An auxiliary commutation device which is provided between three-phase output connections of each switch group has an auxiliary switch constructed as a four-segment switch and a resonance inductance connected in series therewith.

Abstract: A current stiff power conversion system, such as a rectifier, inverter, or AC-to-AC converter is provided wherein power converter switching devices in the power conversion system may be switched at or near zero voltage conditions to minimize or eliminate switching losses and increase switching frequencies. Zero voltage switching conditions are achieved by providing a snubber capacitor across each switching device in the power conversion system, and connecting an active commutation unit, including an inductor and an active commutation unit switching device connected in series across DC bus lines in parallel with the bridge of power conversion switching devices.

Abstract: A rectifier circuit in a three-phase bridge connection includes four-segment main switches. Resonance capacitors are each connected in parallel with a respective one of the main switches. An auxiliary commutation device is connected between two DC terminals. The auxiliary commutation device has an auxiliary four-segment switch and a resonance inductor connected in series therewith.