Abstract:
A method of driving a number of series connected active power semiconductor groups, wherein each of the active power semiconductor groups includes one or more gate oxide-isolated active power semiconductor devices. The method includes generating a current pulse, providing the current pulse to a primary portion of a transformer unit and in response thereto causing a number of reflected current pulses to be reflected at a secondary portion of the transformer unit, and transferring and latching each of the reflected current pulses to create a respective latched gate drive signal, and providing each respective latched gate drive signal to an associated one of the active power semiconductor groups for driving the one or more gate oxide-isolated active power semiconductor devices of the associated one of the active power semiconductor groups. Also, a gate drive circuit that implements the method.
Abstract:
A mechanical arrangement of a multilevel power converter circuit includes a power converter having a first portion with a plurality of first control inputs, at least three direct current voltage inputs, and an alternating current voltage output, and a second portion with a plurality of second control inputs, the at least three direct current voltage inputs and the alternating current voltage output. The second portion is split apart from the first portion. The power converter has at least three levels corresponding to the at least three direct current voltage inputs.
Abstract:
A method of balancing voltages in a group of capacitors of a power electronic device, such as a multilevel power inverter, includes making a balancing determination regarding whether to (i) inject energy into the selected one of the capacitors from an energy storage element, or (ii) extract energy from the selected one of the capacitors into the energy storage element based on the voltage of a selected one of the capacitors, and either injecting energy into the selected one of the capacitors from the energy storage element, or extracting energy from the selected one of the capacitors into the energy storage element based on the balancing determination. Also, a voltage balancing circuit that implements the method. In one particular implementation, a spatial second derivative algorithm is used. In another particular implementation, a comparison to an average capacitor voltage is used.
Abstract:
A drive train comprising an electric machine including a rotor and a stator, the stator being connected to an alternating grid and having a stator frequency, and a bidirectional system for converting an alternating current into another alternating current. The conversion system is connected between the grid and the rotor, and comprises an AC-DC converter connected to the grid, an inverter connected between the AC-DC converter and the rotor, and a device for controlling switches of the inverter according to a control law. The control law is such that the active power exchanged by the inverter with the rotor is essentially always lower than 0.3 times the nominal power of the direct current specifically circulating between the AC-DC converter and the inverter, for the frequencies of a target interval of between 0.6 times the stator frequency and 1.4 times the stator frequency.
Abstract:
A system for converting a first electric voltage into a second electric voltage, comprising: at least two input terminals and two output terminals; and switching members disposed between the terminals, which can convert the first voltage into the second voltage. At least one switching member comprises at least two arms connected in parallel and each arm includes an electronic switch that can be controlled such as to occupy either an on-state or an off-state, said switch comprising a control electrode and two conduction electrodes that conduct current in the on-state. The switching member comprises a common control terminal connected to the control electrode of the switch of each arm, as well as a first common conduction terminal and a second common conduction terminal connected respectively to a first conduction electrode and a second conduction electrode of the switch of each of the arms.
Abstract:
A drive train comprising an electric machine including a rotor and a stator, the stator being connected to an alternating grid and having a stator frequency, and a bidirectional system for converting an alternating current into another alternating current. The conversion system is connected between the grid and the rotor, and comprises an AC-DC converter connected to the grid, an inverter connected between the AC-DC converter and the rotor, and a device for controlling switches of the inverter according to a control law. The control law is such that the active power exchanged by the inverter with the rotor is essentially always lower than 0.3 times the nominal power of the direct current specifically circulating between the AC-DC converter and the inverter, for the frequencies of a target interval of between 0.6 times the stator frequency and 1.4 times the stator frequency.
Abstract:
A motor vehicle power steering system includes a hydraulic pump, an electric motor for driving the pump, and a control unit for controlling the electric motor. The control unit includes means for controlling the power supply voltage applied to the electric motor so that said voltage increases up to a maximum value when the load impedance decreases from its unloaded value, and is at a low value when said load impedance is in the vicinity of its unloaded value.
Abstract:
Controlling an H-bridge of switches, characterized in that during a cycle, the current takes a peak value of constant sign during a continuous portion corresponding to a cycle fraction equal to .vertline. /U.vertline., where is the mean voltage applied to the load and U is the voltage of the DC voltage source, said portion being preceded by a cycle portion corresponding to a cycle fraction equal to 1/2(1-.vertline. /U.vertline.) during which the two switches (I1, I2) of the H-bridge which are connected to ground are closed (or open as the case may be), and followed by a cycle portion likewise corresponding to a cycle fraction equal to 1/2(1-.vertline. /U.vertline.) during which the two switches (I1, I2) of the H-bridge which are connected to ground are open (or closed as the case may be).
Abstract translation:控制开关的H桥,其特征在于,在一个周期期间,电流在对应于等于| V / U |的周期分数的连续部分期间获得恒定符号的峰值,其中V是平均值 施加到负载的电压,U是DC电压源的电压,所述部分之前是对应于等于+ E的周期分数的周期部分,f 1/2 + EE(1 | V / U | ),其中连接到地的H桥的两个开关(I1,I2)是闭合的(或者视情况而定),并且后面是同样对应于等于+ E的周期分数的周期部分, 其中连接到地面的H桥的两个开关(I1,I2)打开(或视情况而定)闭合的1/2 + EE(1 | V / U |)。
Abstract:
A power amplifier circuit that has an inductor and capacitor connected to one end of the output winding of an RF transformer. The other end of the output winding is connected to a resistor that in turn is connected to ground. The transformer has two primary windings. Both primary windings have one end connected to a variable DC voltage supply. The other end of each primary winding is attached to a switch, such as a MOSFET. All three windings are wound around a core. Current flowing from the DC voltage supply to the switches causes a magnetic flux in the core. A voltage is generated on the secondary winding resistor. This voltage is fed back to the switches, controlling on and off timing. In this way the need to measure and record natural frequency is eliminated.
Abstract:
A density and viscosity sensor 1 for measuring density and viscosity of fluid F, the sensor 1 comprising: a resonating element 3, 3A, 3B, 3C, 3D, 3E, 3F, 3G arranged to be immersed in the fluid F, an actuating/detecting element 4, 4A, 4B coupled to the resonating element, a connector 7 for coupling to the actuating/detecting element 4, 4A, 4B, a housing 2 defining a chamber 8A isolated from the fluid F, the housing 2 comprising an area of reduced thickness defining a membrane 9 separating the chamber 8A from the fluid F, the membrane 9 having a thickness enabling transfer of mechanical vibration between the actuating/detecting element 4, 4A, 4B and the resonating element 3, 3A, 3B, 3C, 3D, 3E, 3F, 3G, the actuating/detecting element 4, 4A, 4B is positioned within the chamber so as to be isolated from the fluid F and mechanically coupled to the membrane 9, the resonating element 3, 3A, 3B, 3C, 3D, 3E, 3F, 3G arranged to be immersed in the fluid F is mechanically coupled to the membrane 9, wherein the resonating element 3, 3A, 3B, 3C, 3D, 3E, 3F, 3G has a shape defining a first resonance mode and a second resonance mode characterized by different resonant frequencies F1, F2 and different quality factors Q1, Q2, the first resonance mode moving a volume of fluid, the second mode shearing a surrounding fluid.