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.

Provided are an insulation detection method and apparatus for a fuel cell vehicle, and a vehicle. The method comprises: determining whether a vehicle is started; when the vehicle is started, executing the following steps: controlling a battery management system to perform the first insulation detection; detecting whether a fuel cell is started; and when the fuel cell is not started, controlling a fuel cell control unit to perform second insulation detection, wherein an insulation detection module for performing insulation detection on the fuel cell is provided in the fuel cell control unit of the vehicle.

An insulation fault response method for a fuel cell vehicle, comprising: when a vehicle starts, detecting whether a fuel cell is in a startup state or not; when the fuel cell is not in the startup state, reading a first insulation resistance detected by a fuel cell control unit and a second insulation resistance detected by a cell management system; when the first insulation resistance indicates that the vehicle is in an insulation fault, executing a first control policy; and when the second insulation resistance indicates that the vehicle in an insulation fault, executing a second control policy, wherein the first control policy is different from the second control policy, and wherein when the first insulation resistance is less than a first threshold and/or the second insulation resistance is less than a second threshold, the vehicle is in an insulation fault.

The method for measuring of quick changes of low surface conductivity of dielectrics under electromagnetic interference of line voltage is based on a comparison measurement on a voltage divider and synchronisation of measuring pulses with periodic sinusoidal course of interference when voltage with pre-set parameters of square pulse is brought to the tested dielectric surface and potential is sampled in the voltage divider consisting of the measured dielectric surface and a resistor with preselected resistivity in certain time intervals both before application of the measuring pulse and immediately before its end, and then based on a difference between the values measured using a differential amplifier, the value corresponding to that measured without effect of electromagnetic interference 60 Hz is derived and the result is the possibility to measure quick changes of low surface conductivity of dielectric surface.

The equipment for measurement of quick changes of low surface conductivity of dielectrics under electromagnetic interference of line voltage contains the sensing element (1) monitoring electromagnetic interference and the block (2) monitoring electromagnetic interference that is connected to the sensing element, and the comparative block (3) for control of generation of time sequences is connected to the first output from the block (2) and the block (4) for generation of pulses is also connected to the first output from the block (2), and the output of the block (4) are square pulses 1 ms/±5 V, and the first output 10 μs/±5 V and the second output 10 μs/±5 V are connected to inputs of the block (6) of logic elements, and another output of the block (2) monitoring electromagnetic interference is connected to the comparative element (5), the output of which is connected to the fourth input of the block (6) of logic elements, and the first output of the bloc (6) of logic elements is connected through the block (7) for modulation of pulses to the with the output as pulse 0 to 300 mV to the tested surface in the block (8) of the voltage divider surface/divider-resistor where output from this block (8) of the voltage divider surface/resistor-divider is connected through the block (11) of the voltage follower to the divider with very high input impedance to signal inputs of the first sample-and-hold amplifier (9) and of the second sample-and-hold amplifier (10), and the second input for control of sampling of the first sample-and-hold amplifier (9) and the second input for control of sampling of the second sample

Disclosed herein are methods for determining resistance in an electric circuit, including the steps of: applying a voltage pulse to a test point of said electric circuit, said voltage pulse having a predetermined pulse duration; measuring an electric observable at a response point of said electric circuit during at least a part of said pulse duration; estimating during said pulse duration an expectation value from said measured observable; and determining said resistance from said expectation value. Also disclosed herein are devices for determining resistance in an electric circuit.

A method for automatically creating installation-specific measuring profiles for an insulation monitoring system, includes: assisting in a computer-controlled manner by means of an assist system via guided instructions for acquiring installation data; and executing the instructions by means of one more sensor devices. The method further includes pre-selecting, assisting, recording, evaluating, detecting, and optimizing steps.

An earth fault detection apparatus includes a switch group configured to switch between a first measurement path including a battery and a capacitor, and a second and third measurement paths including the battery, a positive/negative-side insulation resistance, and the capacitor; a reference resistance and a test switch; and a control unit calculating a first reference value based on each charging voltage in a case where the test switch is opened and the capacitor is charged, and calculating the insulation resistance with reference to a conversion map created to correspond to an electrostatic capacitance between a power supply line and ground, wherein the control unit calculates a second reference value based on each charging voltage in a case where the test switch is closed and the capacitor is charged for a shorter time, and estimates the electrostatic capacitance with reference to a predetermined test conversion map.

A method detects an electrical insulation fault between an electric power source and an electrical ground, via a circuit that includes a controllable voltage generator and an electrical measuring resistor connected in series between a terminal of the electric power source and the electrical ground. The method includes controlling the voltage generator to establish, between its terminals, a non-zero voltage value, and measuring the voltage at the terminals of the electrical measuring resistor to detect an electrical insulation fault between the electric power source and the electrical ground. The method further includes a computer determining, depending at least on the voltage measured at the terminals of the electrical measuring resistor, at least two parameters characteristic of a disturbance affecting the detection of the electrical insulation fault, and calculating a reliability level of the detection of the electrical insulation fault depending on at least one of the two parameters.

The present invention relates to an apparatus and a method capable of calculating insulation resistances and parasitic capacitances of a battery outside the battery. In the present invention, when a positive electrode connector and a negative electrode connector are coupled to a positive electrode terminal and a negative electrode terminal of the battery, respectively, and a ground connector is coupled to a case of the battery, even though the battery is positioned inside a chamber in order to perform a temperature test or the like of the battery, the insulation resistances and the parasitic capacitances of the battery may be calculated without needing to move the battery to the outside of the chamber. Accordingly, the insulation resistances and the parasitic capacitances of the battery may be conveniently calculated.

The present disclosure includes: a signal generation unit for applying a pulse signal to an electric line; a signal measurement unit for measuring the voltage of an applied pulse signal from the ground, when the pulse signal is applied to the ground through insulation resistance; an average voltage calculation unit for calculating the average voltage of the voltages measured during a period depending on sampling intervals; and a control unit for calculating the sampling intervals on the basis of an initial sampling interval and a preset time multiple, calculating the average voltage during the sampling period according to the calculated sampling intervals, and, according to whether the difference between a calculated first average voltage and a second average voltage measured before the first average voltage is within a first error range, detecting the first average voltage as a normal voltage, or calculating the sampling intervals by applying different time multiples thereto.