A DC to AC converter includes an input configured to receive a DC input voltage, an output and two serially connected capacitors connected across the output. The two serially connected capacitors including a first capacitor and a second capacitor connected together at a connection node. The converter also includes a first parallel converter connected between the input and the connection node and a second parallel converter connected between the input and the connection and in parallel with the first parallel converter. The converter also includes a controller that selectively connects the first and second parallel converters to the input based on a first duty cycle (D1) and second duty cycle (D2), respectively. The controller determines D1 based on comparing a desired alternating current signal across the second first to a measured alternating current signal across the first capacitor such that D1 varies over time.

A power converting apparatus for applying to a load an alternating-current voltage converted from a direct-current voltage includes an inverter that receives a PWM signal and applies the alternating-current voltage to the load and an inverter control unit that generates the PWM signal and supplies the PWM signal to the inverter. The frequency of the PWM signal is integer multiples of the frequency of the alternating-current voltage. The alternating-current voltage includes a plurality of positive pulses and a plurality of negative pulses in one cycle of the alternating-current voltage. The number of the positive pulses and the number of the negative pulses are equal.

The invention relates to a modular multilevel converter (2) having a control module (4) and a computer (10) for computing a setpoint for the internal energy of the converter stored in the capacitors of the submodules of the arms. The control module is configured to deduce, from the setpoint for the internal energy of the converter, a setpoint for the voltage across the terminals of each modeled capacitor, which setpoint is used for regulating the voltage across the points of common coupling between the converter and the DC power supply network and the voltage across the terminals of each modeled capacitor.

The present invention discloses a single-phase non-isolated inverter, comprising: a first DC-side capacitor, a second DC-side capacitor, a first switch unit, a second switch unit, a third switch unit, a fourth switch unit, a fifth switch unit, a sixth switch unit, a seventh switch unit, and an eighth switch unit. When the single-phase non-isolated inverter is operated at a zero-voltage switching state, the seventh switch unit and the eighth switch unit are switched to short circuit for forming a short-circuit path between the bus lines. Briefly speaking, this novel single-phase non-isolated inverter has reactive power capability. In addition, according to an adjusting signal of a PI controller, micro controller of the single-phase non-isolated inverter is able to properly adjusts the duty cycle of a switch unit driving signal of the fifth switch unit and the sixth switch unit, so as to cancel the capacitor voltage unbalance between two DC-side capacitors.

An apparatus may include a first device having a first metal structure, a first metal element, and a first transistor. The first metal structure may include first and second surfaces, that are flat and opposite facing. The first metal element may include first and second surfaces that are flat and opposite facing. The first transistor may include first and second terminals between which 1 amp or more of electrical current is transmitted when the first transistor is activated, wherein the first and second terminals may include first and second surfaces, respectively, that are substantially flat and opposite facing. The second surface of the first metal structure can be electrically and thermally connected to a bus bar. The first and second surfaces of the first and second terminals, respectively, may be sintered to the first and second surfaces, respectively, of the first metal structure and the first metal element, respectively.

A frequency generator for generating a working frequency for a transmission signal of a rail contact of an axle counter includes a series resonant circuit having a transmitter coil unit of the rail contact and a capacitor. The frequency generator has an inverter, the output of which is connected to the capacitor. The inverter is configured to generate an oscillating voltage and to feed the generated oscillating voltage to the transmitter coil unit of the rail contact via the capacitor. A current transformer synchronizes the output voltage of the inverter to the current in the series resonant circuit. A start-up circuit electrically connected to the inverter is configured to trigger the inverter and to be electrically connected to an input power supply. The frequency generator is a robust and effective circuit for generation of magnetic fields where manufacturing effort and expensive components can be reduced.

A frequency generator for generating a working frequency for a transmission signal of a rail contact of an axle counter includes a series resonant circuit having a transmitter coil unit of the rail contact and a capacitor. The frequency generator has an inverter, the output of which is connected to the capacitor. The inverter is configured to generate an oscillating voltage and to feed the generated oscillating voltage to the transmitter coil unit of the rail contact via the capacitor. A current transformer synchronizes the output voltage of the inverter to the current in the series resonant circuit. A start-up circuit electrically connected to the inverter is configured to trigger the inverter and to be electrically connected to an input power supply. The frequency generator is a robust and effective circuit for generation of magnetic fields where manufacturing effort and expensive components can be reduced.

The present invention relates to resonant power converters and inverters comprising a self-oscillating feedback loop coupled from a switch output to a control input of a switching network comprising one or more semiconductor switches. The self-oscillating feedback loop sets a switching frequency of the power converter and comprises a first intrinsic switch capacitance coupled between a switch output and a control input of the switching network and a first inductor. The first inductor is coupled in-between a first bias voltage source and the control input of the switching network and has a substantially fixed inductance. The first bias voltage source is configured to generate an adjustable bias voltage applied to the first inductor. The output voltage of the power converter is controlled in a flexible and rapid manner by controlling the adjustable bias voltage.

An alternating current (AC) to direct current (DC) power converter may have a connector with a pair of power supply contacts and a pair of data contacts. An electronic device may be connected to the connector of the power converter. The power converter may supply DC power to the electronic device using the power supply contacts. The power converter may include control circuitry that has a resistor coupled across the data contacts. When the electronic device and the power converter are connected to each other, each may advertise to the other that capabilities are present that exceed industry standards. At the same time, standard-compliant discovery operations may be performed to probe the value of the resistance of the resistor that is coupled across the data contacts. When extended capabilities are discovered, extended functions may be performed including accelerated charging functions and data communications functions.

An alternating current (AC) to direct current (DC) power converter may have a connector with a pair of power supply contacts and a pair of data contacts. An electronic device may be connected to the connector of the power converter. The power converter may supply DC power to the electronic device using the power supply contacts. The power converter may include control circuitry that has a resistor coupled across the data contacts. When the electronic device and the power converter are connected to each other, each may advertise to the other that capabilities are present that exceed industry standards. At the same time, standard-compliant discovery operations may be performed to probe the value of the resistance of the resistor that is coupled across the data contacts. When extended capabilities are discovered, extended functions may be performed including accelerated charging functions and data communications functions.