An inverter system includes a converter, an inverter, a first switch SW1 that connects between the converter and an AC power source, a capacitor that smooths a DC power in a DC bus, a resistor Rr connected from a positive voltage side of the DC bus to ground, a second switch SW2 that connects between the resistor Rr and ground, and a controller that controls drive of the inverter system. The controller is configured to: after charging the capacitor, while the first switch SW1 is in an OFF state, turn on the second switch SW2 and obtain a first across voltage E.sub.R1 of the resistor Rx; turn on an element, among semiconductor elements of the inverter, that is connected to the negative voltage side of the DC bus, and then obtain a second across voltage E.sub.R2 of the resistor Rx; and inspect insulation resistance of a motor based on the across voltages E.sub.R1, E.sub.R2.

An insulation resistance inspection system for a battery module cell pouch for inspecting an insulation resistance state of a cell pouch in the battery module configured by assembling a plurality of battery cells includes: an inspection unit bringing each of a plurality of probe modules into contact with an end surface of the cell pouch to measure an insulation resistance of the cell pouch; an interface unit connected to the inspection unit to receive a signal for the measured insulation resistance of the cell pouch; and a control unit receiving the signal for the insulation resistance of the cell pouch through the interface unit to determine whether the cell pouch is in good condition or in poor condition depending on whether the signal for the insulation resistance of the cell pouch is within a normal range that is a reference of good quality.

A device for determining the electrical resistance of a system includes a field effect electron emitter capable of emitting electrons when the electrical emission potential V.sub.e of the electron emitter is higher than a threshold value V.sub.L, with the emitting end of the emitter being at least partially conductive; an item of equipment capable of determining the electrical emission potential V.sub.e of the electron emitter; a voltage source adapted to apply a potential difference E to the device and to generate an electric field at the emitter, an electron detector capable of detecting all or some of the electrons emitted by the electron emitter so as to measure the intensity of the current I.sub.mes flowing between the emitter and the detector; electrical connection means adapted to electrically connect the system and the device in such a way that the current intensity flowing between the emitter and the detector can also pass through the system.

The present invention relates to an apparatus capable of measuring an insulation resistance of a battery, and according to the apparatus capable of measuring the insulation resistance of the present invention. A voltage measurement unit may measure a voltage with respect to a potential of a negative terminal of a battery rather than the ground, and thus parameters requiring a high precision may be measured using one device, thereby reducing cost, and, because a first sensing substrate and a second sensing substrate are separated, different potentials may be used as the ground, thereby securing a better insulation performance between the first sensing substrate that is an HV side and the second sensing substrate that is an LV side.

An apparatus including an electrical cable provided with light emitters along its length for visual communication of its position/extent and of statuses of the apparatus, said statuses including at least statuses related an insulation resistance between conductors of the electrical cable. The apparatus is provided with a power unit enabling status updates and light emission also when the electrical cable is disconnected and thus not in use.

The present application discloses a circuit and a method for detecting insulation resistance. The circuit includes: a first voltage dividing module, a second voltage dividing module, a third voltage dividing module, a fourth voltage dividing module, a first switch module, a fifth voltage dividing module, a second switch module, a third switch module, and a detecting module, where the first voltage dividing module comprises a first voltage dividing unit and a second voltage dividing unit, and the third voltage dividing module comprises a third voltage dividing unit and a fourth voltage dividing unit. According to the embodiments of the present application, errors caused by fluctuations in the pull-up of the reference power supply can be avoided, and the accuracy of the circuit for detecting insulation resistance can be effectively improved.

A controller (1) forms an insulation measurement path and turns on a third switch connected in parallel to a capacitor, (2) after a lapse of a first time period turns off the third switch, and (3) detects an insulation abnormality based on a voltage of the capacitor measured after a lapse of a second time period after the turning off of the third switch.

A method and a monitoring device for selectively determining a partial insulation resistance and a partial system leakage capacitance of an outgoing line in a branched ungrounded power supply system which is monitored using an insulation monitoring device which actively superposes a measuring alternating voltage on the ungrounded power supply system. With an equivalent circuit diagram of the branched ungrounded power supply system as a basis, the partial insulation resistance having the current/voltage ratios applicable in linear systems are derived from the known measuring voltage and the inner resistance of the insulation monitoring device and from the total insulation resistance and the stationary partial current measured in the corresponding outgoing line and in the settled state. To calculate the partial system leakage capacitance, the temporal derivative of the measured non-stationary conductor-to-ground voltage is evaluated in conjunction with the non-stationary partial current and the previously determined partial insulation resistance.

An electric leakage detection apparatus for a battery included in an electric vehicle transmits a first voltage corresponding to a voltage between a negative terminal of the battery and a chassis of the electric vehicle to an analog-to-digital converter through a capacitor. The electric leakage detection apparatus transmits a second voltage corresponding to a voltage between a positive terminal of the battery and the chassis to the analog-to-digital converter through the capacitor. The analog-to-digital converter outputs digital signals indicating the first voltage and the second voltage using the negative terminal as the ground. The electric leakage detection apparatus determines the first voltage and the second voltage based on the digital signals, and detects an electric leakage between the battery and the chassis based on the first voltage and the second voltage.

A ground fault detection device comprising a capacitor which serves as a flying capacitor, a switch group which switches between a V0-charging path, a Vcn-charging path, a Vcp-charging path and a charging voltage measurement path for the capacitor, and a controller which controls the switch group and calculates an insulation resistance based on V0, Vcn and Vcp, wherein V0 is a measured value on the V0-charging path, Vcn is a measured value on the Vcn-charging path, and Vcp is a measured value on the Vcp charging path, wherein, if Vcn can be considered as zero, the controller switches to the Vcp-charging path and performs measurement while keeping a charged state of the capacitor, wherein Vcp obtained after discharging the capacitor is subtracted from a measured value obtained from the measurement in order to calculate Vcn.