A thyristor circuit includes at least one branch including at least one thyristor, a thyristor control circuit and a current detector. The current detector is configured to detect a current value representative of an electrical current flowing through the thyristor and to input the detected current value into the thyristor control circuit. The thyristor control circuit is configured to determine a fault condition in which the detected current value exceeds a predetermined current threshold based on a deteriorated blocking ability of the thyristor. Dependent on the determination result, the thyristor control circuit triggers the thyristor into a conductive state.

A power supply system includes: a semiconductor switch (1) that is turned on at the time of normal supply from a commercial AC power supply (5); a first current detector (CT1) including a transformer (10) and configured to detect an AC input current (I1); a second current detector (CT2) including a Hall effect sensor (20) and configured to detect an AC output current (I2); and a failure detector (30) that determines that one of a pair of thyristors (1a, 1b) included in the semiconductor switch (1) has misfired when the detection values from the first and second current detectors (CT1, CT2) are not equal at the time of normal supply from the commercial AC power supply (5).

A power supply system includes: a semiconductor switch (1) that is turned on at the time of normal supply from a commercial AC power supply (5); a first current detector (CT1) including a transformer (10) and configured to detect an AC input current (I1); a second current detector (CT2) including a Hall effect sensor (20) and configured to detect an AC output current (I2); and a failure detector (30) that determines that one of a pair of thyristors (1a, 1b) included in the semiconductor switch (1) has misfired when the detection values from the first and second current detectors (CT1, CT2) are not equal at the time of normal supply from the commercial AC power supply (5).

An arrangement for a refrigerator and/or freezer comprising an electrical or electronic component (1, 2a), and comprising detection means (2, 4) by which an electrical or thermal load of the component can be detected, wherein the detection means comprise a heat source (2) and means for the detection (4) of the heat output of the heat source, wherein the heat source is not formed by the component itself and is connected in series or in parallel to the component.

A solid state switch for connecting and disconnecting an electrical device has at least one FET-type device and at least one thyristor-type device coupled in parallel to the at least one FET-type device. A gate driver is operative to send gate drive signals to the at least one FET-type device and to the at least one thyristor-type device for providing current to the electrical device. The gate driver is constructed to control a split of the current as between the at least one FET-type device and the at least one thyristor-type device.

A crowbar circuit includes a first inductor coupled to a positive terminal of a power supply at a first terminal, and at a second terminal coupled in series with a main thyristor having a main gate drive for limiting a discharge current through main thyristor; a resistor coupled to the main thyristor at a first terminal and to the negative terminal at a second terminal; an auxiliary thyristor having an auxiliary gate drive coupled in series with a first capacitor at a first terminal and an auxiliary inductor at a second terminal, the auxiliary inductor coupled between the first terminal of the resistor and the first capacitor; a first diode couple between the first terminal of the resistor and the first terminal of the auxiliary thyristor; and a second diode coupled between the positive terminal and the negative terminal.

A thyristor circuit includes at least one branch including at least one thyristor, a thyristor control circuit and a current detector. The current detector is configured to detect a current value representative of an electrical current flowing through the thyristor and to input the detected current value into the thyristor control circuit. The thyristor control circuit is configured to determine a fault condition in which the detected current value exceeds a predetermined current threshold based on a deteriorated blocking ability of the thyristor. Dependent on the determination result, the thyristor control circuit triggers the thyristor into a conductive state.

A circuit breaker locator/tester is made more effective and efficient by appropriately dealing with inherent temperature variations. During operation of the circuit breaker locator/tester, large amounts of current are pulsed through various components, resulting in significant heating effects. These pulses of large amounts of current are generated in relatively brief time periods. While components are designed to manage and deal with various heating effects, excessive heating can degrade performance and efficiency. Various monitoring devices and heat anticipation systems are included within the locator/tester to deal with these conditions. In certain embodiments, temperature monitoring components are included, which provides a clear indication of sensed temperatures at specific locations within the device. In addition, systems are also provided to concurrently monitor operation of the device and provide operational control so that undesirable operating conditions are not encountered. Using these operational monitoring systems, appropriate delays can be incorporated which will naturally allow for heat dissipation.

The present invention relates to a grid-connected type renewable energy power generation system comprising: a power generation unit for producing and outputting electric energy; an energy storage unit for storing electric energy produced and output from the power generation unit; a power conversion unit for supplying electric energy output from the power generation unit of the energy storage unit to a load or a gird; and a switching unit configured by a switching semiconductor for electric power, the switching semiconductor being connected between the power conversion unit and the grid and enabling active switching control, wherein when energy is independently supplied to the load by the power conversion unit or an abnormality occurs in the power conversion unit, an off signal is applied to a gate of the switching semiconductor enabling active switching control of the switching unit.

A crowbar circuit includes a first inductor coupled to a positive terminal of a power supply at a first terminal, and at a second terminal coupled in series with a main thyristor having a main gate drive for limiting a discharge current through main thyristor; a resistor coupled to the main thyristor at a first terminal and to the negative terminal at a second terminal; an auxiliary thyristor having an auxiliary gate drive coupled in series with a first capacitor at a first terminal and an auxiliary inductor at a second terminal, the auxiliary inductor coupled between the first terminal of the resistor and the first capacitor; a first diode couple between the first terminal of the resistor and the first terminal of the auxiliary thyristor; and a second diode coupled between the positive terminal and the negative terminal.