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 rotating machine power conversion device is obtained which achieves operational continuation in a rotational speed range in which the operational continuation is enabled, even when a single phase of an electrical power conversion device made of switching devices causes a disconnection or turn-off failure. The rotating machine power conversion device comprises: a normality-case/abnormality-case current control device selection device for transferring between a normality-case current control device and an abnormality-case current control device in accordance with a determination result of an abnormality determination device; and an abnormality-case current control device/power conversion halt device selection device, using a rotational speed calculation device, for transferring between the abnormality-case current control device used when a rotational speed is lower than that being prespecified, and the power conversion halt device used when a rotational speed is higher than that being prespecified.

A frequency converter, includes: a DC link, wherein the DC link has a first connection pole at which a positive link potential is present during operation of the frequency converter, and a second connection pole at which a negative link potential is present during operation of the frequency converter; an inverter, wherein the inverter has a first connection pole at which a positive inverter potential is present during operation of the frequency converter, and a second connection pole at which a negative inverter potential is present during operation of the frequency converter; a resistive shunt which is looped in between the first connection pole of the DC link and the first connection pole of the inverter; a differential amplifier which is designed to generate a test voltage from a potential difference across the resistive shunt; and an evaluation unit which is designed to detect a ground fault based on the test voltage.

A dual-input power conversion system includes a first primary side power network comprising a first hold-up capacitor, wherein the first primary side power network has inputs configured to be coupled to a first power source, and outputs coupled to a transformer, a second primary side power network comprising a second hold-up capacitor, wherein the second primary side power network has inputs configured to be coupled to a second power source, and outputs coupled to the transformer, and a secondary side power network having inputs coupled to a secondary side of the transformer, and outputs coupled to a load, wherein the first primary side power network and the second primary side power network are configured such that a voltage across one of the first hold-up capacitor and the second hold-up capacitor is maintained by a voltage reflected from the secondary side to a corresponding primary side.

Each cell of a cell assembly for a converter may include: first and second terminals, switching elements, and a capacitor. The cells are connected in series such that, for each pair of neighbouring cells, the first terminal of a first cell is connected to the second terminal of a second cell. Each cell includes a bypass connected to the first and second terminals that bypasses switching elements in a short circuit configuration and does not bypass the switching elements in an open circuit configuration. Each cell has a cell controller providing control signals to the sw itching elements to connect the capacitor to the first and second terminals or to bypass the capacitor. The cell controller provides a control signal to the bypass unit of neighbouring cells to change its configuration between the short circuit and open circuit configurations.

The present invention provides a glitch detector including a first inverter, a second inverter, a first capacitor and a second capacitor. The first inverter is connected between a supply voltage and a ground voltage, and is configured to receive a first signal at a first node to generate a second signal to a second node. The second inverter is connected between the supply voltage and the ground voltage, and is configured to receive the second signal at the second node to generate the first signal to the first node. A first electrode of the first capacitor is coupled to the supply voltage, and a second electrode of the first capacitor is coupled to the first node. A first electrode of the second capacitor is coupled to the ground voltage, and a second electrode of the second capacitor is coupled to the second node.

A power converter includes at least one arm having a plurality of converter cells cascaded to each other. Each of the converter cells includes a pair of input/output terminals, a plurality of switching elements, and a power storage element. The power storage element is electrically connected to the input/output terminals through the switching elements. A control device generates a control signal for controlling on and off of the switching elements of each converter cell. The control device generates the control signal by pulse width modulation control based on a modulation command signal including an AC component having a fundamental frequency and corresponding to a command value of an output voltage between the input/output terminals, in each converter cell, such that a harmonic component included in the output voltage and having a predetermined frequency that is an integer multiple of the fundamental frequency is suppressed.

A power supply used to convert an input voltage into an output voltage, and the power supply includes an input detection circuit, a conversion circuit, a detection circuit, and a controller. The input detection circuit provides a power good signal or a power fail signal according to the input voltage. The conversion circuit converts the input voltage into an output voltage, and the detection circuit detects the output voltage according to the power good signal to accordingly provide an output feedback signal with a first feedback value. The controller stabilizes a voltage level of the output voltage according to the first feedback value. The detection circuit self-adjusts a feedback condition according to the power fail signal, and correspondingly adjusts the output feedback signal to a second feedback value according to the feedback condition. The controller reduces the voltage level of the output voltage according to the second feedback value.

There is provided a switching valve for a voltage source converter, the switching valve comprising a plurality of modules, each module including at least one switching element and at least one energy storage device, each switching element and each energy storage device in each module arranged to be combinable to selectively provide a voltage source, the switching valve including a regulator programmed to selectively control the switching of the switching elements to select one or more of the modules to contribute a respective voltage to a switching valve voltage, wherein the regulator is programmed to selectively regulate an energy stored in each energy storage device by controlling the switching of the switching elements to regulate a voltage of each energy storage device towards a target voltage, and the regulator is programmed to vary the target voltage of each energy storage device as a function of a number of healthy modules.

In a power conversion device in which cell converters are connected in series, each cell converter includes: main circuit conductors connecting switching elements and a capacitor to each other; a bypass portion disposed between two external terminals connected to other cell converters; external output conductors connecting the external terminals and the main circuit conductors to each other; and bypass connection conductors connecting the external output conductors and the bypass portion to each other. The bypass connection conductors or the external output conductors are disposed so as to oppose each other at a high-potential side and a low-potential side thereof. The conductors are bent so as to have portions at which currents in parts of the conductors have the same direction. Thus, mutual inductances and self-inductances are increased, whereby short-circuit current flowing to the bypass portion at the time of double failures is suppressed.