Disclosed in the present disclosure are an insulation resistance detection circuit, a resistance detection method, a converter and a photovoltaic centrifuge. The insulation resistance detection circuit includes a resistance detection module connected between a positive electrode and a negative electrode of a direct-current bus to be detected. The resistance detection module includes a first resistance bridge and a second resistance bridge arranged in parallel. The first resistance bridge is connected to the positive electrode of the direct-current bus by means of a first sampling resistor R1. The second resistance bridge is connected to the negative electrode of the direct-current bus by means of a second sampling resistor R2, and both the first sampling resistor R1 and the second sampling resistor R2 are equipped with voltage sampling chips. The resistance detection module is configured to calculate an insulation resistance value of the direct-current bus according to voltage values of the two sampling resistors before and after a first switch S is switched.

It is described a leakage compensation circuit for a measurement device which comprises a measurement circuit with a leaking device that is connected to a measurement path and causes a leakage current. The leakage compensation circuit comprises: i) a replica device of the leaking device, wherein the replica device is connected to a replica path, and wherein the replica device is configured to cause a replica leakage current that is essentially equal to the leakage current of the leaking device, ii) a voltage regulator which is connected to the measurement path and to the replica path, wherein the voltage regulator is configured to regulate the voltage in the replica path based on the voltage of the measurement path, and iii) a current mirror which is connected to the measurement path and to the replica path, wherein the current mirror is configured to mirror the replica leakage current of the replica device into the measurement path.

Provided is an insulation resistance monitoring device that enables measurement of insulation resistance using a mega tester without removing the insulation resistance monitoring device. The insulation resistance monitoring device that monitors the insulation resistance of an object to be measured such as a motor includes: a current detecting unit that is connected between the power supply line and the ground line of the motor and detects a current flowing through the insulation resistance of the motor; a voltage generating unit connected between the power supply line and the ground line of the motor; and a switch for opening and closing the connection path between the power supply line or the ground line of the motor and the voltage generating unit, wherein the off resistance when the connection path is opened is 100 MΩ or more.

A battery system having a battery pack with a negative pole, a positive pole and a battery cell, a coupling network having a first negative terminal and a first positive terminal, a pack voltage divider, and a coupling voltage divider. The first positive terminal is connectable to the positive pole via a switch. Optionally, the first negative terminal is connectable to the negative pole via a switch. The pack voltage divider includes a two resistors connected between the positive pole and a first reference point. A negative pack measurement resistor and a negative sub-pack measurement resistor are dis-connectable from the negative pole or the first reference point via a switch. A positive coupling measurement resistor and a positive sub-coupling measurement resistor are connected between the first positive terminal and the first reference point. Two resistors are connected between the first negative terminal and the first reference point.

A method for detecting an insulation fault in a vehicle on-board electrical system having an HV and LV on-board electrical system branches. The LV branch has at least one first LV potential and a second LV potential that differs therefrom and corresponds to a ground potential of the vehicle on-board electrical system. The HV branch has positive HV negative HV potentials. These HV potentials are DC-isolated from the LV branch potentials. An insulation fault between at least one of the HV potentials and the first LV potential is detected by identifying a current flow. The current flow runs through a voltage limiting circuit connected between the ground potential and the first LV potential. This circuit connects the first LV potential, via a plurality of diodes, to a voltage limiting element connected to the ground potential of the vehicle on-board electrical system. A vehicle overvoltage protective circuit is also described.

An insulation resistance tester for testing for insulation resistance of a battery includes a solution supply unit, and a test unit configured to receive a conductive solution from the solution supply unit and to establish a contact with a test target through the conductive solution such that insulation resistance of the test target is measured.

The disclosure relates to an insulation resistance detection device and a forklift truck. The insulation resistance detection device includes a detection module, a voltage conditioning module, and a control module. The device uses a first voltage dividing unit and a second voltage dividing unit to replace the inverting amplifier circuit, to obtain a positive voltage corresponding to the voltage of the negative electrode of the battery to be detected with respect to the first reference ground, thereby reducing costs of the insulation resistance detection device. The control module calculates the first insulation resistance of the positive electrode of the battery to be detected with respect to the first reference ground and the second insulation resistance of the negative electrode of the battery to be detected with respect to the first reference ground according to the first voltage and the third voltage.

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.

An apparatus and battery system for estimating insulation resistance including an insulation resistance measurement circuit connected to a first electrode of a battery, a first switch connected to the first resistor, a second resistor connected to the first switch, a third resistor connected to the second resistor and a second electrode of the battery, and a second switch connected between a first contact point between the first switch and the second resistor and a chassis ground, a voltage measurement part measuring a voltage of a second contact point between the second resistor and the third resistor, and a controller controlling the first and second switches and calculating an insulation resistance value based on the voltage measured at the second contact point the first and second switches are ON, and the voltage measured at the second contact point while the first switch is OFF and the second switch is ON.

In a ground fault detection apparatus, a first charge voltage of a detection capacitor measured with a positive electrode side of a high-voltage battery connected in series with a positive electrode side end of the detection capacitor and a negative electrode side end of the detection capacitor grounded, is compared with a second charge voltage of the detection capacitor measured with the positive electrode side end of the detection capacitor grounded and the negative electrode side of the high-voltage battery connected in series with the negative electrode side end of the detection capacitor. When the first charge voltage is smaller and degree of smallness is greater than a predetermined reference, it is determined that positive electrode side insulation resistance is decreased. When the second charge voltage is smaller and degree of smallness is greater than a predetermined reference, it is determined that negative electrode side insulation resistance is decreased.