An apparatus and a method for measuring insulation resistance of a battery pack using an insulation resistance meter (IRM) circuit where only a negative relay is electrically conducted, thereby decreasing a risk of electric shock when insulation resistance is measured in a state where an external insulation resistor of the battery pack is broken.

The present invention is a method of determining at least two equivalent insulation resistances for an electric system including a power source (2), an inverter (11), an electric load (3) and a measurement circuit (5). Measurements are performed during operation of the electric system, when the controlled switches of inverter (11) are in a zero sequence. The present invention also relates to a control system implementing same.

The present disclosure provides a parameter selection method, apparatus, and computer readable storage medium for an insulation detection circuit. The parameter selection method includes determining an allowable injection frequency range of an AC signal to be injected, according to a predetermined resistance range of an insulation resistance of the power battery under test and a predetermined resistance calculation cycle of the insulation resistance; and selecting an output frequency of the signal generation module according to a lowest frequency to be generated by the signal generation module and the allowable injection frequency range.

An insulation resistance measuring apparatus designed to calculate a complex impedance of an ac circuit including a measuring resistor, a coupling capacitor, an insulation resistor installed in a vehicle, and a ground capacitance. The insulation resistance measuring apparatus includes a sine wave current applying device which applies an ac signal to the measuring resistor and measures a voltage change appearing at a junction of the sine wave current applying device and the measuring resistor. The ac signal and the voltage change are used to determine the complex impedance. A resistance value of the insulation resistor is calculated as a function of the complex impedance. This structure enables the circuit to be reduced in size.

An insulation resistance measuring device for detecting insulation resistance of an electric vehicle comprises a battery system, a measuring unit, a control unit and a calculation unit. The measuring unit comprises a circuit module comprises a plurality of resistances connected between a positive side and a negative side of the battery system, a first switch, a second switch, and a voltage detecting unit. The first switch is connected between the circuit module and a ground side. The second switch is connected between the circuit module and the negative side. The voltage detecting unit is arranged at a connecting node of the resistances of the circuit module. The control unit is configured to control the first switch and the second switch to turn on or turn off. The calculation unit is configured to calculate a high potential insulation resistance and a low potential insulation resistance of the electric vehicle.

The present disclosure provides an insulation detection circuit and method, and a battery management system. The circuit includes a first isolation module, a voltage division module, a signal generation module, first and second sampling points and a processor. A first end of the first isolation module is connected to a power battery, and a second end of the first isolation module is connected to the second sampling point. The signal generation module is connected to the first sampling point and configured to inject an AC signal into the power battery and provide the first sampling point with a first sampled signal. A first end of the voltage division module is connected to the first sampling point, and a second end of the voltage division module is connected to the second sampling point. The processor is configured to calculate an insulation resistance of the power battery.

An example method measures a leakage characteristic of a signal path. The example method includes forcing a current onto the signal path; determining a parasitic capacitance of the signal path based on a rate of change of a voltage on the signal path resulting from the current; forcing a voltage onto the signal path for a period of time; and following the period of time, determining the leakage characteristic based on the parasitic capacitance and a rate of change in voltage on the signal path from the forced voltage.

A ground fault detection apparatus includes a control unit, a detection capacitor, a positive-electrode-side first resistor connected to positive-electrode side of a high-voltage battery, a negative-electrode-side first resistor connected to negative-electrode side of the high-voltage battery, a positive-electrode-side second resistor where one end is grounded and voltage of another end is measured by the control unit, a negative-electrode-side second resistor having one end grounded, a positive-electrode-side C contact switch that switches connection destination of one end of the detection capacitor between a path including the positive-electrode-side first resistor and a path including the positive-electrode-side second resistor based on instruction from the control unit, a negative-electrode-side C contact switch that switches connection destination of another end of the detection capacitor between a path including the negative-electrode-side first resistor and a path including the negative-electrode-side second resistor based on instruction from the control unit, and a path switching C contact switch.

This disclosure describes techniques to identify and mitigate an effect of a power interruption that impacts the operation of Radio Frequency (RF) antennas associated with a telecommunications network. More specifically, an Adaptive Voltage Modification (AVM) controller is described that is configured to monitor and detect a change in voltage that occurs during a power transmission from a Direct Current (DC) power source to a Remote Radio Unit (RRU). A power interruption may include a power disruption or a power surge. The AVM controller may be configured to cause a potential transformer that is coupled between the DC power source and the RRU to incrementally step-up or step-down the voltage of a power transmission from the DC power source. In this way, the AVM controller may preemptively mitigate an impact of a power interruption on Quality of Service (QoS) parameters associated with signal data transmitted by the RF antennas.

At least one aspect of the disclosure is directed to a power conversion unit (PCU). The PCU includes a power converter circuit, a safety detection circuit including a plurality of known network impedances and a switch having a first end coupled between two of the plurality of network impedances and a second end coupled to an output terminal, and a controller communicatively coupled to the safety detection circuit and the at least one power converter circuit. The controller may be configured to operate the switch, determine one or more voltage values of the safety detection circuit, and calculate an insulation impedance based at least in part on the one or more voltage values, a position of the switch, and the plurality of known network impedances.