A shoot-through protection circuit includes a current sensor providing a sensor signal connected to a comparator input via at least a burden resistor. A switch protection circuit including a protection input connected to an output of the comparator and a plurality of outputs. Each of the outputs is connected to a corresponding switch in a plurality of stacked switches. Wherein the switch protection circuit is configured to drive each switch of the plurality of stacked switches open in response to a positive output signal from the comparator.

A short circuit protection apparatus for a power conversion apparatus supplying power to a load via a plurality of switches connected to each other in parallel includes Ma current detectors each configured to detect a sum of currents flowing through two or more switches among the plurality of switches so as to output a detection signal indicative of the sum that is detected, wherein Ma is 1 less than M, which is the number of the plurality of switches, and a short circuit determiner configured to determine, based on detection signals obtained from the respective Ma current detectors, occurrence of short circuit failure in the plurality of switches to output a cutoff instruction signal for stopping on-off drive of the plurality of switches.

A power supply may include a power converter circuit may be configured to control a magnitude of an output voltage, and generate a signal indicative of the magnitude of the output voltage. The power supply may include an over-power protection circuit that is configured to receive a feedback signal indicative of a magnitude of an input current of the power converter circuit. The power supply may include a control circuit that is configured to determine a magnitude of a requested power based on the signal indicative of the magnitude of the output voltage, and disable the power supply (e.g., control the magnitude of the output voltage to be zero volts) when the magnitude of the requested power is greater than a second threshold and the magnitude of input power indicated by the first feedback signal is less than a third threshold.

An apparatus according to an embodiment includes a control circuit to control operations of an inverter and a switch. The control circuit judges whether or not a power system has a power failure, based on values of the system voltage and a frequency of the power system; and calculates a phase difference between a phase of the output voltage of the inverter and a phase of the system voltage and generate, by means of the phase difference, an output frequency pattern for changing a frequency of the output voltage of the inverter. The control circuit, when it is judged that the power system has recovered from the power failure, controls the inverter to change the frequency of the output voltage of the inverter in line with the output frequency pattern, and closes the switch after the phase difference becomes smaller than or equal to a threshold.

The invention discloses a commutation failure protection method, and apparatus, computer device and storage medium thereof. The method comprises: collecting three-phase AC currents on a valve-side of a converter, a DC current on a high-voltage side and a DC current on a neutral terminal; selecting a minimum value of an absolute value of the three-phase AC currents on the valve side as an AC characteristic quantity, and selecting a maximum value of the DC current on the high-voltage side and the DC current on the neutral terminal as a DC characteristic quantity; according to the AC characteristic quantity and the DC characteristic quantity, constructing a minimum characteristic quantity; comparing the minimum characteristic quantity with a first preset threshold, and outputting a commutation judgment result; according to the commutation judgment result, constructing a commutation time interval; comparing the commutation time interval with a second preset threshold and a third preset threshold, and outputting a commutation failure protection judgment result to determine whether a commutation failure occurs. The invention uses minimum current sequence characteristics to track a commutation process of a converter valve, and when a commutation failure occurs, it may make timely, accurate and reliable judgment, thereby ensuring safe operation of valve equipment.

In an installation including a stored energy source and an electric motor which can be fed by an inverter, and a method for operating an installation, the stored energy source forms an electrical series circuit with a first fuse and further fuse(s). A controllable contact, e.g., a switch, a contactor, etc., is connected in parallel to the further fuse, or a respective controllable contact, e.g., a switch, a contactor, etc., is connected in parallel to each of the further fuses. The series circuit feeds the DC-voltage-side connection of the inverter, and a device for detecting the voltage applied to the series circuit is connected to control electronics which generate a control signal for the contact or control signals for the controllable contacts. For example, the respective contact is opened when the voltage falls below a respective voltage threshold.

A circuit for minimizing energy provided to a ground fault includes a source, a multiple switches, an output filter, and a controller. The switches include a first side pair of switches and a second side pair of switches configured to provide an output signal based on the source. The output filter includes one or more energy storage elements coupled to the first side pair of switches or the second side pair of switches. The controller is configured to receive a ground fault signal that indicates a fault has occurred and configured to generate a switch signal for the switches for a minimum energy state of the output filter and in response to the ground fault signal.

A power conversion circuit has a controller with an input terminal and a circuit configured to drive an electric current out of the input terminal in response to a condition of the controller. An indicator is coupled to the input terminal of the controller. The controller includes a clock signal controlling the electric current out of the input terminal. The input terminal is a voltage sensing terminal or feedback input terminal in some embodiments.

A circuit for minimizing energy provided to a ground fault includes a source, a multiple switches, an output filter, and a controller. The switches include a first side pair of switches and a second side pair of switches configured to provide an output signal based on the source. The output filter includes one or more energy storage elements coupled to the first side pair of switches or the second side pair of switches. The controller is configured to receive a ground fault signal that indicates a fault has occurred and configured to generate a switch signal for the switches for a minimum energy state of the output filter and in response to the ground fault signal.

Self-diagnostic method (100) of open-circuit fault, in power switching blocks of a modular inverter comprising a plurality (k=1 . . . n) of blocks (31a, 32a, 33a, 34a, 31b, 32b, 33b, 34b, 31c, 32c, 33c, 34c) in parallel per phase leg (5, 5a, 5b, 5c), and being provided with temperature sensors (6), said method comprising: —sampling and storing (130) temperatures data (I) of said n blocks in a phase leg measured by said temperature sensors at relevant sampling times t.sub.SD with a relevant sampling interval Δt.sub.SD; —comparing (150) said temperature data (I) of each (k) block with previously sampled and stored temperature data (II) of said each (k) block and considering a possible fault (FF) on one of said blocks if the following condition is not fulfilled: (III) where Th is a predefined temperature deviation threshold; or —comparing (250) current temperature data (I) of each (k) block with current average temperature data (VI) and considering a fault (OF) on one of said blocks if the following condition is not fulfilled: (V) where Th.sub.AV is a predefined average temperature deviation threshold. The invention concerns also a test comprising a shoot-through procedure to identify open circuits in a block.