A frequency support system arranged for providing frequency support to an AC grid. The system includes an ES arrangement, and a bi-directional DC/AC power electronic converter interface configured for connecting the ES arrangement with the grid. The ES arrangement includes a plurality of series connected ES groups, each ES group including a plurality of parallel connected ES modules, each ES module including an energy storage interfaced by a bi-directional power electronic ES converter configured for connecting the ES with a DC side of the converter interface.

A frequency support system arranged for providing frequency support to an AC grid. The system includes an ES arrangement, and a bi-directional DC/AC power electronic converter interface configured for connecting the ES arrangement with the grid. The ES arrangement includes a plurality of series connected ES groups, each ES group including a plurality of parallel connected ES modules, each ES module including an energy storage interfaced by a bi-directional power electronic ES converter configured for connecting the ES with a DC side of the converter interface.

A cascaded multilevel converter is disclosed. The converter comprises a plurality of modules coupled to form a branch, each of the modules comprising a switching circuit and a DC link for supplying DC voltage to the switching circuit. The converter further comprises a controller for controlling the switching circuit of each module to generate an AC voltage in the branch, wherein the controller is configured to: determine for each module a voltage across a capacitor of the DC link of the module, determine for each module a reference power value for charging the capacitor of the DC link of the module to a reference voltage value for the module, determine, from the reference power values of the modules, a common reference AC current value for AC current in the branch, determine, from the common reference AC current value, a common reference AC voltage value for AC voltage in the branch.

A power conversion device capable of shortening the time required for acceleration of a motor and a metal processing device including the power conversion device are provided. Then, a power conversion device 10 includes a converter 100 configured to convert an AC voltage from outside to a DC voltage Vo and a converter controller 107 configured to control the converter 100. The converter 100 includes a voltage doubler circuit 104 configured to boost the DC voltage Vo when activated, and outputs the DC voltage Vo having a voltage value different in accordance with the activation and stop of the voltage doubler circuit 104. The converter controller 107 activates the voltage doubler circuit 104 at a first time that is earlier by a predetermined period than a second time at which a speed command value ω* of the motor 130 rises from a predetermined value.

A power conversion device capable of shortening the time required for acceleration of a motor and a metal processing device including the power conversion device are provided. Then, a power conversion device 10 includes a converter 100 configured to convert an AC voltage from outside to a DC voltage Vo and a converter controller 107 configured to control the converter 100. The converter 100 includes a voltage doubler circuit 104 configured to boost the DC voltage Vo when activated, and outputs the DC voltage Vo having a voltage value different in accordance with the activation and stop of the voltage doubler circuit 104. The converter controller 107 activates the voltage doubler circuit 104 at a first time that is earlier by a predetermined period than a second time at which a speed command value ω* of the motor 130 rises from a predetermined value.

A regulating device includes a voltage regulator configured to receive an input voltage and regulate an amplitude and a frequency of the input voltage to generate an electrical signal acting on the electric control functional layer; and a controller coupled to the voltage regulator and configured to receive a regulating signal, and to send a control signal to the voltage regulator according to the regulating signal to regulate the amplitude and the frequency of the input voltage, the control signal including an amplitude parameter and a frequency parameter of the voltage. Finer regulation of the optical characteristics of the electric control functional layer can be realized by introducing frequency regulation. Such finer regulation can bring about a more comfortable experience to human senses. At the same time, the realization of such fine regulation enables more diversified control of the electronic control function layer.

A regulating device includes a voltage regulator configured to receive an input voltage and regulate an amplitude and a frequency of the input voltage to generate an electrical signal acting on the electric control functional layer; and a controller coupled to the voltage regulator and configured to receive a regulating signal, and to send a control signal to the voltage regulator according to the regulating signal to regulate the amplitude and the frequency of the input voltage, the control signal including an amplitude parameter and a frequency parameter of the voltage. Finer regulation of the optical characteristics of the electric control functional layer can be realized by introducing frequency regulation. Such finer regulation can bring about a more comfortable experience to human senses. At the same time, the realization of such fine regulation enables more diversified control of the electronic control function layer.

Example three-level inverters, control methods, and systems are provided. One example three-level inverter includes a first bus capacitor, a second bus capacitor, a power conversion circuit, and a controller. The first bus capacitor is connected in the middle of the current bus and the power conversion circuit. The power conversion circuit is configured to convert a direct current into a three-phase alternating current for output. The controller is configured to determine a balance reference by using a difference between absolute values of voltages of the positive and negative direct current buses and an even harmonic current in a grid-connected current, where the balance reference is used to enable the three-level inverter to generate a current signal for balancing the voltages of the positive and negative direct current buses.

An electronic device utilizing a wireless charging system is provided. The electronic device includes a power source, a transmission coil, a full-bridge inverter electrically connected to the power source and the transmission coil, and a control circuit which communicates with an external device through the transmission coil, and controls the full-bridge inverter to transmit a power signal through the transmission coil. The control circuit may: receive, from the external device, a first control signal requesting that the power of the power signal be reduced to less than a specified power, in response to the first control signal, adjust the duty cycle of each of first to fourth gate signals for controlling the full-bridge inverter, and switch to a pulse width modulation (PWM) drive state in which an operation according to a first period and an operation according to a second period are alternately repeated.

The AC/DC converter according to one embodiment of the present invention comprises: a power unit comprising a plurality of power input lines; a main bridge circuit into which input power is input via the power unit; a relay connected in parallel to both ends of any one of the power input lines; and a control unit for controlling the opening/closing of the relay on the basis of the type of input power.