Abstract: An apparatus for use in conjunction with a goal having a frame defining an opening is provided. The apparatus includes at least two movable blockers adapted to selectively define a target space within the opening. First and second blockers are perpendicular and mounted on portions of the frame. The first blocker has a pair of opposed horizontal first free edges defining a first free space between the first free edges and movable in a vertical direction to increase or decrease the first free space therebetween. The second blocker has a pair of opposed vertical second free edges defining a second free space between the second free edges and movable in a horizontal direction to increase or decrease the second free space therebetween. The first free space and the second free space define the target space.

Abstract: The present disclosure provides a control circuit to control power to a load, a typically load being a heating element. The control circuit is preferably comprised of a switch, such as a TRIAC switch, to switch from a first state to a second state. An energy bank, such as a capacitor, is also provided, the energy bank to store energy to power a thermostat when the switch is in a non-conducting state. The control circuit is also comprised of a drive circuit to actuate the switch back and forth from the first state to the second state. The improved control circuit has been shown to have reduced conducted electromagnetic interference, which is advantageous to meet ever stricter government guidelines for circuitry conducted EMI.

Abstract: The present disclosure relates to a circuit for providing a current from a source to a load. A commutation cell includes a main switch that controls a voltage applied by the source to the load. An opposite switch maintains the current in the load when the load is disconnected from the source by the main switch. The opposite switch returns the load current to the main switch when the main switch connects again the load to the source. The disclosed circuit configuration reduces recovery current, losses and electromagnetic losses. A synchronizing controller controls opening and closing sequences of the main switch and of the opposite switch. The disclosed circuit can provide a DC-DC voltage converter. Combining two such circuits can provide a DC-AC voltage converter.

Abstract: The present disclosure relates to a commutation cell and to a compensation circuit for limiting overvoltage across the power electronic switch of the commutation cell and for limiting a recovery current in a freewheel diode of the commutation cell. The power electronic switch has a parasitic emitter inductance. A variable gain compensation circuit generates a feedback from a voltage generated across the parasitic inductance of the emitter of the power switch at turn-on or turn-off of the power electronic switch. The compensation circuit provides the feedback to a control of the power electronic switch to reduce the voltage generated on the parasitic emitter inductance. A power converter including the commutation cell with the compensation circuit is also disclosed.

Abstract: The present disclosure relates to a power converter configured for limiting switching overvoltage. The power converter comprises a bottom commutation cell that includes a bottom power electronic switch and a bottom compensation circuit connected to a bottom parasitic inductance. The bottom compensation circuit applies a sample of the voltage induced across the bottom parasitic inductance at turn-off of the bottom power electronic switch to the reference node of the bottom gate driver. The power converter also comprises a top commutation cell that includes top power electronic switch and a top compensation circuit connected to the bottom parasitic inductance. The top compensation circuit applies a sample of the voltage induced across the bottom parasitic emitter upon turn-off of the top power electronic switch to the reference node of the top gate driver.

Abstract: A physical topology for receiving top and bottom power electronic switches comprises a top collector trace connected to a positive voltage power supply tab and having a connection area for a collector of a top power electronic switch, a bottom emitter trace connected to a negative voltage power supply tab and having a connection area for an emitter of the bottom power electronic switch, and a middle trace connected to a load tab and having a connection area for an emitter of the top power electronic switch and a connection area for a collector of the bottom power electronic switch. Sampling points are provided on the traces for voltages on the emitters of the top and bottom power electronic switches, on the trace for voltage of the collector of the bottom power electronic switch, and on the negative voltage power supply tab. The topology defines parasitic inductances.

Abstract: A turn-off overvoltage limiting for IGBT is described herein. The injection of a sample of the overvoltage across the IGBT in the gate drive to slow down the slope of the gate voltage decrease only during the overvoltage above a predetermined value is described herein. Techniques to increase the parasitic inductance to allow the control to limit an overvoltage at turn off of the second IGBT are also described herein.

Abstract: The present disclosure relates to a circuit for providing a current from a source to a load. A commutation cell includes a main switch that controls a voltage applied by the source to the load. An opposite switch maintains the current in the load when the load is disconnected from the source by the main switch. The opposite switch returns the load current to the main switch when the main switch connects again the load to the source. The disclosed circuit configuration reduces recovery current, losses and electromagnetic losses. A synchronizing controller controls opening and closing sequences of the main switch and of the opposite switch. The disclosed circuit can provide a DC-DC voltage converter. Combining two such circuits can provide a DC-AC voltage converter.

Abstract: The present disclosure relates to a power converter configured for limiting switching overvoltage. The power converter comprises a bottom commutation cell that includes a bottom power electronic switch and a bottom compensation circuit connected to a bottom parasitic inductance. The bottom compensation circuit applies a sample of the voltage induced across the bottom parasitic inductance at turn-off of the bottom power electronic switch to the reference node of the bottom gate driver. The power converter also comprises a top commutation cell that includes top power electronic switch and a top compensation circuit connected to the bottom parasitic inductance. The top compensation circuit applies a sample of the voltage induced across the bottom parasitic emitter upon turn-off of the top power electronic switch to the reference node of the top gate driver.

Abstract: The present disclosure introduces a gate driver used to drive a power electronic switch of a commutation cell. The gate driver comprises a turn-off current source connected to a gate of the power electronic switch and an additional current source. The additional current source is in parallel to the turn-off current source of the gate driver and is configured to control a collector to emitter voltage variation at turn off of the power electronic switch. A circuit combining the gate driver with a commutation cell having a power electronic switch, a circuit combining a pair of gate drivers with a leg having two commutation cells including two power electronic switches and a converter including such circuits are also disclosed.

Abstract: A physical topology for receiving top and bottom power electronic switches comprises a top collector trace connected to a positive voltage power supply tab and having a connection area for a collector of a top power electronic switch, a bottom emitter trace connected to a negative voltage power supply tab and having a connection area for an emitter of the bottom power electronic switch, and a middle trace connected to a load tab and having a connection area for an emitter of the top power electronic switch and a connection area for a collector of the bottom power electronic switch. Sampling points are provided on the traces for voltages on the emitters of the top and bottom power electronic switches, on the trace for voltage of the collector of the bottom power electronic switch, and on the negative voltage power supply tab. The topology defines parasitic inductances. Sample voltages can be supplied to gate driver references.

Abstract: A commutation cell is configured for limiting switching overvoltage. The commutation cell includes a power electronic switch having a parasitic emitter inductance through which a voltage is generated upon turning off of the power electronic switch. The commutation cell also includes a dynamically controlled compensation circuit connected to the parasitic emitter inductance. The compensation circuit applies a controllable portion of the voltage generated through the parasitic emitter inductance at turn-off of the power electronic switch to control the voltage generated through the parasitic emitter inductance. A power converter includes a pair of commutation cells and a compensation circuit of the commutation cell.

Abstract: The present topology for controlled power switch module is concerned with a module where the parasitic inductance of the emitter of the top power switch is optimized to allow the injection of a sample of the overvoltage across this parasitic inductance in the gate drive circuit of the top power switch as a feedback to slow down the slope of the falling gate voltage during an overvoltage that is above a predetermined value.

Abstract: The present disclosure relates to a power converter configured for limiting switching overvoltage. The power converter comprises a pair of commutation cells. Each commutation cell includes a power electronic switch and a gate driver connected to a gate of the power electronic switch. A reference of the gate driver of a first commutation cell is connected to a ground of the power converter while a reference of the gate driver of a second commutation cell is connected to a collector of the power electronic switch of the first commutation cell. The gate driver of the second commutation cell has no negative voltage power input, either through using a single voltage power supply or by connecting a negative voltage connection of the dual voltage power supply to ground.

Abstract: The present disclosure relates to a compensation circuit for independently controlling turn-on and turn-off of a power electronic switch through a gate driver. The compensation circuit includes a circuit path sampling a first portion of a voltage induced across an inductance of the power electronic switch at turn-on. Another circuit path samples a second portion of the voltage induced across the inductance of the power electronic switch at turn-off. The compensation circuit further includes a gate driver reference connection configured to respectively supply the sampled portions of the voltage during turn-on and turn-off of the power electronic switch. A compensation circuit controlling a first power electronic switch in parallel with a second power electronic switch, a commutation cell and a power converter having a pair of parallel legs, in which each power electronic switch is provided with the compensation circuit, are also disclosed.

Abstract: A turn-off overvoltage limiting for IGBT is described herein. The injection of a sample of the overvoltage across the IGBT in the gate drive to slow down the slope of the gate voltage decrease only during the overvoltage above a predetermined value is described herein. Techniques to increase the parasitic inductance to allow the control to limit an overvoltage at turn off of the second IGBT are also described herein.

Abstract: A turn-off overvoltage limiting for IGBT is described herein. The injection of a sample of the overvoltage across the IGBT in the gate drive to slow down the slope of the gate voltage decrease only during the overvoltage above a predetermined value is described herein. Techniques to increase the parasitic inductance to allow the control to limit an overvoltage at turn off of the second IGBT are also described herein.

Abstract: The present disclosure relates to a compensation circuit for independently controlling turn-on and turn-off of a power electronic switch through a gate driver. The compensation circuit includes a circuit path sampling a first portion of a voltage induced across an inductance of the power electronic switch at turn-on. Another circuit path samples a second portion of the voltage induced across the inductance of the power electronic switch at turn-off. The compensation circuit further includes a gate driver reference connection configured to respectively supply the sampled portions of the voltage during turn-on and turn-off of the power electronic switch. A compensation circuit controlling a first power electronic switch in parallel with a second power electronic switch, a commutation cell and a power converter having a pair of parallel legs, in which each power electronic switch is provided with the compensation circuit, are also disclosed.

Abstract: The present disclosure relates to a commutation cell configured for limiting switching overvoltage. The commutation cell includes a power electronic switch having a parasitic emitter inductance through which a voltage is generated upon turning off of the power electronic switch. The commutation cell also includes a dynamically controlled compensation circuit connected to the parasitic emitter inductance. The compensation circuit applies a controllable portion of the voltage generated through the parasitic emitter inductance at turn-off of the power electronic switch to control the voltage generated through the parasitic emitter inductance. A power converter comprising a pair of commutation cells and a compensation circuit of the commutation cell are also disclosed.

Abstract: The present disclosure relates to a power converter configured for limiting switching overvoltage. The power converter comprises a pair of commutation cells. Each commutation cell includes a power electronic switch and a gate driver connected to a gate of the power electronic switch. A reference of the gate driver of a first commutation cell is connected to a ground of the power converter while a reference of the gate driver of a second commutation cell is connected to a collector of the power electronic switch of the first commutation cell. The gate driver of the second commutation cell has no negative voltage power input, either through using a single voltage power supply or by connecting a negative voltage connection of the dual voltage power supply to ground.