An insulation resistance detection circuit and method are disclosed. The circuit includes a controller configured to: open a first relay, and close second relays, or switch an on/off status of at least one of the second relays; determine, based on a first measurement value between a positive input terminal of an inverter circuit and an earthing point, whether the positive input terminal of the inverter circuit is short-circuited or has low resistance to protective earthing; and determine, based on a second measurement value between a negative input terminal of the inverter circuit and the earthing point, whether the negative input terminal of the inverter circuit is short-circuited or has low resistance to protective earthing, where the first relay is one of in M relays and is connected to at least one impedor in parallel, and the second relays are relays other than the first relay in the M relays.

An insulation resistance detection circuit and method are disclosed. The circuit includes a controller configured to: open a first relay, and close second relays, or switch an on/off status of at least one of the second relays; determine, based on a first measurement value between a positive input terminal of an inverter circuit and an earthing point, whether the positive input terminal of the inverter circuit is short-circuited or has low resistance to protective earthing; and determine, based on a second measurement value between a negative input terminal of the inverter circuit and the earthing point, whether the negative input terminal of the inverter circuit is short-circuited or has low resistance to protective earthing, where the first relay is one of in M relays and is connected to at least one impedor in parallel, and the second relays are relays other than the first relay in the M relays.

Provided is an apparatus for delivering electrical power, in particular for delivering regeneratively produced electrical power, which has at least one converter and at least one filter for matching the delivery of power by the converter to a load impedance. Also provided is a method for operating the apparatus for delivering electrical power which allows improved monitoring of the functioning of the filters or mains filters and which uses means for determining at least one filter current in at least one filter, which means are designed in such a manner that said means make it possible to determine the at least one filter current during operation of the apparatus. Comparison means are provided and generate an error information signal using the desired value and actual value of the filter current and a predefinable error criterion.

Provided is an apparatus for delivering electrical power, in particular for delivering regeneratively produced electrical power, which has at least one converter and at least one filter for matching the delivery of power by the converter to a load impedance. Also provided is a method for operating the apparatus for delivering electrical power which allows improved monitoring of the functioning of the filters or mains filters and which uses means for determining at least one filter current in at least one filter, which means are designed in such a manner that said means make it possible to determine the at least one filter current during operation of the apparatus. Comparison means are provided and generate an error information signal using the desired value and actual value of the filter current and a predefinable error criterion.

By detecting a temperature abnormality of a power semiconductor by using the power semiconductor as a temperature sensor, it is possible to detect deterioration and an abnormality of elements, a drive circuit and a cooling system, prevent a failure during an operation by taking an appropriate measure in advance, and make a system operational life long. More specifically, a power converting device which includes the power semiconductor and an arithmetic operation circuit which gives a drive instruction to the power semiconductor detects the temperature abnormality of the power semiconductor based on the drive instruction of the power semiconductor and a delay time of a control drive voltage applied to the power semiconductor to protect the power converting device. The power converting device which includes the power semiconductor and the arithmetic operation circuit gives the drive instruction compares and determines a delay time of the drive instruction and a control voltage applied to the power semiconductor and a reference value, and changes at least one of the drive instruction and the drive voltage based on a result of the comparison and the determination.

An inverter system failure is detected on the basis of the currents of respective phases detected by a current detection unit when carrying out switching control in accordance with a first drive mode in which all switching elements on a lower-side arm are switched on and all switching elements on an upper-side arm are switched off, and the currents of respective phases detected by the current detection unit when carrying out switching control in accordance with a second drive mode in which all of the switching elements on the upper-side arm are switched on and all of the switching elements on the lower-side arm are switched off.

A testing device of an inverter device includes a power supply device including an AC-DC conversion circuit for converting AC power received from an AC power supply into DC power and a control part for controlling the AC-DC conversion circuit and a filter circuit interposed between a tested inverter device to be tested and the power supply device, having a reactor and a capacitor, and delivering the DC power output from the power supply device to the tested inverter device. The control part is configured to execute output adjustment of the AC-DC conversion circuit when a test start signal is generated to start an instantaneous voltage abnormality test which is a test changing magnitude of power supply voltage of the AC power supply in a predetermined direction being either one of increase or decrease during operation of the tested inverter device and the power supply device.

A testing device of an inverter device includes a power supply device including an AC-DC conversion circuit for converting AC power received from an AC power supply into DC power and a control part for controlling the AC-DC conversion circuit and a filter circuit interposed between a tested inverter device to be tested and the power supply device, having a reactor and a capacitor, and delivering the DC power output from the power supply device to the tested inverter device. The control part is configured to execute output adjustment of the AC-DC conversion circuit when a test start signal is generated to start an instantaneous voltage abnormality test which is a test changing magnitude of power supply voltage of the AC power supply in a predetermined direction being either one of increase or decrease during operation of the tested inverter device and the power supply device.

A driver circuit arrangement for driving a transistor bridge, which includes at least a first half-bridge composed of a low-side transistor and a high-side transistor, is described herein. In accordance with one example of the description, the circuit includes a current source and a detection circuit. The current source is operably coupled to the high-side transistor of the first half-bridge and configured to supply a test current to the first half bridge. The detection circuit is configured to compare a voltage sense signal, which represents the voltage across the high-side transistor of the first half-bridge, with at least one first threshold to detect, dependent on the result of this comparison, whether a short-circuit is present in the first half-bridge.

Devices and methods are provided, which detect a short circuit condition related to a semiconductor switch. A short circuit condition may be determined when a control signal of the switch exceeds a first reference, and a change of load current of the switch exceeds a second reference.