Abstract: A creeping discharge element drive device of an embodiment includes a switching element, a current detector, a zero-cross detection circuit, a storage, and a controller. The current detector detects alternating currents flowing through the switching element. The zero-cross point detection circuit detects a zero-cross point of the alternating currents. The storage stores a first threshold value of a resonant period. The controller drives the switching element to apply a test voltage to the creeping discharge element, determines a resonant period of the alternating currents from the detected zero-cross points of the alternating currents, and restricts or stops the driving of the switching element in response to the resonant period exceeding the first threshold value.

Abstract: A creeping discharge element drive device of an embodiment includes a switching element, a current detector, a zero-cross detection circuit, a storage, and a controller. The current detector detects alternating currents flowing through the switching element. The zero-cross point detection circuit detects a zero-cross point of the alternating currents. The storage stores a first threshold value of a resonant period. The controller drives the switching element to apply a test voltage to the creeping discharge element, determines a resonant period of the alternating currents from the detected zero-cross points of the alternating currents, and restricts or stops the driving of the switching element in response to the resonant period exceeding the first threshold value.

Abstract: A power converter connected between a direct current power supply and a load, the power converter including a switching unit energizing the load based on inputted control signal, a voltage detector detecting a voltage of the direct current power supply, and a protection operation portion detecting a steep elevation of the voltage and performing protection operation to stop a switching operation by the switching unit, wherein the protection operation portion includes an addition circuit adding a predetermined voltage to the voltage detected by the voltage detector and a delay time generator connected to an output of the addition circuit, and wherein the protection operation is performed when a difference between the voltage detected by the voltage detector and an output voltage of the delay time generator reaches a certain value.

Abstract: A power converter connected between a direct current power supply and a load, the power converter including a switching unit energizing the load based on inputted control signal, a voltage detector detecting a voltage of the direct current power supply, and a protection operation portion detecting a steep elevation of the voltage and performing protection operation to stop a switching operation by the switching unit, wherein the protection operation portion includes an addition circuit adding a predetermined voltage to the voltage detected by the voltage detector and a delay time generator connected to an output of the addition circuit, and wherein the protection operation is performed when a difference between the voltage detected by the voltage detector and an output voltage of the delay time generator reaches a certain value.

Abstract: A wind power generation system according to an embodiment includes a blade; a lightning protection device; an electric device; a voltage application mechanism; a first lightning arrester element; and a second lightning arrester element. The lightning protection device includes a receptor provided at the blade and guides a current of lightning to the ground from the receptor via a lightning conductor. The electric device is installed at the blade and includes a first electric conductor and a second electric conductor provided apart from each other. The voltage application mechanism applies a voltage between the first electric conductor and the second electric conductor. The first lightning arrester element has one end thereof electrically connected to the first electric conductor and has the other end thereof grounded. The second lightning arrester element has one end thereof electrically connected to the second electric conductor and has the other end thereof grounded.

Abstract: A wind power generation system according to an embodiment includes a blade; a lightning protection device; an electric device; a voltage application mechanism; a first lightning arrester element; and a second lightning arrester element. The lightning protection device includes a receptor provided at the blade and guides a current of lightning to the ground from the receptor via a lightning conductor. The electric device is installed at the blade and includes a first electric conductor and a second electric conductor provided apart from each other. The voltage application mechanism applies a voltage between the first electric conductor and the second electric conductor. The first lightning arrester element has one end thereof electrically connected to the first electric conductor and has the other end thereof grounded. The second lightning arrester element has one end thereof electrically connected to the second electric conductor and has the other end thereof grounded.

Abstract: In one embodiment, system for driving an electromagnetic appliance includes an electromagnetic appliance, a main-drive unit and a sub-drive unit. The electromagnetic appliance includes coils for n number of phases, the coils for each of the n phases being arranged in a pair and wound so as to be excited in a predetermined direction by being energized with opposite-phase currents. The main drive unit is connected to each of the coils and energizes the paired coils with opposite-phase currents. The sub-drive unit is provided parallel with the main-drive unit and is configured to suppress a short-circuit current occurring at the main-drive unit when switching energization of the coils.

Abstract: A switching control device controls a drive circuit including one or more series circuits each one of which includes an upper switching element and a lower switching element. The switching control device includes an upper side temperature detection unit detecting a temperature of the upper switching element (hereinafter, “an upper side temperature”), a lower side temperature detection unit detecting a temperature of the lower switching element (hereinafter, “a lower side temperature”), and a signal generation circuit adding an offset value to a command voltage of a PWM signal output to the upper and lower switching elements to generate and output a PWM signal to the switching elements so that the upper and lower side temperatures approximate to each other.

Abstract: A switching control device controls a drive circuit including one or more series circuits each one of which includes an upper switching element and a lower switching element. The switching control device includes an upper side temperature detection unit detecting a temperature of the upper switching element (hereinafter, “an upper side temperature”), a lower side temperature detection unit detecting a temperature of the lower switching element (hereinafter, “a lower side temperature”), and a signal generation circuit adding an offset value to a command voltage of a PWM signal output to the upper and lower switching elements to generate and output a PWM signal to the switching elements so that the upper and lower side temperatures approximate to each other.

Abstract: A DC-DC converter includes a main reactor disposed in a main energization path, a first main switching element disposed in the main energization path and on-off controlled to cause current flowing through the main reactor to intermittently flow, a second main switching element forming a discharge loop configured to discharge electrical energy stored in the main reactors to the DC voltage output terminal side, an auxiliary reactor disposed between the first main switching element and the main reactor, an auxiliary switching element discharging electrical energy stored in the reactors through the main reactor to the DC voltage output terminal side in the main energization path, diodes connected reversely in parallel to the respective main switching elements and the auxiliary switching element, and a series circuit connected in parallel to the auxiliary reactor and including a diode with an anode located at the main reactor side and a capacitor.

Abstract: A DC-DC converter includes smoothing capacitors, switching circuits and capacitor circuits at a primary-side and a secondary-side of a high frequency transformer respectively. When a midpoint voltage of the capacitor circuit is detected by a voltage detection unit, a timing signal output unit is configured to supply to a drive circuit a timing signal according to a switching operation carried out by the primary-side or secondary-side switching circuit, in synchronization with a period in which a winding voltage of the high frequency transformer changes, based on a change in the midpoint voltage.

Abstract: An inverter device includes a DC positive input line and a DC negative input line, a main bridge which includes a pair of series-connected switching elements with diodes being connected in reverse parallel with the switching elements respectively, an auxiliary bridge which includes a pair of series-connected switching elements with diodes being connected in reverse parallel with the switching elements respectively and a current-limiting reactor. A plurality of sets each one of which includes the main bridge and the auxiliary bridge is connected between the DC positive and negative input lines. Each set constitutes a phase. The current-limiting reactor is connected between a common connection point of both switching elements of the main bridge and a common connection point of both switching elements of the auxiliary bridge in each set.

Abstract: In one embodiment, system for driving an electromagnetic appliance includes an electromagnetic appliance, a main-drive unit and a sub-drive unit. The electromagnetic appliance includes coils for n number of phases, the coils for each of the n phases being arranged in a pair and wound so as to be excited in a predetermined direction by being energized with opposite-phase currents. The main drive unit is connected to each of the coils and energizes the paired coils with opposite-phase currents. The sub-drive unit is provided parallel with the main-drive unit and is configured to suppress a short-circuit current occurring at the main-drive unit when switching energization of the coils.

Abstract: An inverter device includes a DC positive input line and a DC negative input line, a main bridge which includes a pair of series-connected switching elements with diodes being connected in reverse parallel with the switching elements respectively, an auxiliary bridge which includes a pair of series-connected switching elements with diodes being connected in reverse parallel with the switching elements respectively and a current-limiting reactor. A plurality of sets each one of which includes the main bridge and the auxiliary bridge is connected between the DC positive and negative input lines. Each set constitutes a phase. The current-limiting reactor is connected between a common connection point of both switching elements of the main bridge and a common connection point of both switching elements of the auxiliary bridge in each set.

Abstract: A DC-DC converter includes a main reactor interposed in a main energization path extending from a DC voltage input terminal to a DC voltage output terminal, a first main switching element interposed into the main energization path so as to be on-off controlled so that current flowing across the main reactor is intermitted, a second main switching element forming a discharge loop discharging electrical energy stored in the main reactor to the DC voltage output terminal side, an auxiliary reactor interposed between the first main switching element and the main reactor in the main energization path, an auxiliary switching element discharging electrical energy via the main reactor to the DC voltage output terminal side, the electrical energy being stored in the auxiliary and main reactors, and diodes connected in reverse parallel with the first and second main switching elements and the auxiliary switching elements respectively.