Wide deployment of high voltage battery systems in traction, industrial and renewable energy installations is raising the concerns for human safety. Exposure to hazardous high voltages may occur due to deterioration of insulation materials or by accidental events. It is thus important to monitor for such faults and being able to provide timely warnings to affected persons. For this purpose it has become mandatory for electrified passenger vehicles (CFR 571.305) to maintain high isolation values which can be continuously monitored by electrical isolation monitoring devices. The task of monitoring isolation resistance within the electrically noisy car environment is not a trivial task and the solution to this problem has become quickly a field of research and innovation for all affected industries.

Embodiments of the present invention disclose methods and systems in a vehicle having high voltage (HV) for measuring isolation impedance in an EV or HEV utilizing an AC impedance measurement system. The method utilizes an extraction algorithm based on a Fourier transform to calculate phase and amplitude and then utilizes the calculated phase and amplitude to determine the isolation impedance. The isolation impedance comprises leakage resistance and total capacitance that are coupled in parallel between the high voltage system and the chassis. Embodiments of the present invention also provide a method and systems for component value self-calibration.

A system may include a resistive-inductive-capacitive sensor, a driver configured to drive the resistive-inductive-capacitive sensor at a driving frequency, a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and configured to measure phase information and amplitude associated with the resistive-inductive-capacitive sensor, and a noise detection circuit communicatively coupled to the measurement circuit and configured to determine a presence of external interference in the system based on at least one of the phase information and the amplitude information.

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 impedance detection apparatus for an earphone plug, including: an earphone jack unit; a voltage sampling unit comprising a first resistor connected between a positive terminal of a power supply and a contact access point, a negative terminal of the power supply being in contact with the jack end ground wire contact; a contact selection unit comprising selection switches arranged in one-to-one correspondence with selected jack end connection contacts, each of the selection switches being connected between a corresponding connection contact and the contact access point; a processing unit configured to calculate an impedance value of an equivalent impedance between the selected connection contact and the jack end ground wire contact according to the voltage of the contact access point with respect to the jack end ground wire contact; and a display unit.

An electrical system includes a voltage bus, voltage sensor(s) measuring a first voltage between a positive bus rail and electrical ground, and a second voltage between a negative bus rail and electrical ground, a bias resistor, and a controller. When the switch is closed, the controller measures four or more discrete voltage samples of the first and second voltages. The samples are grouped into first and second sample groups each having three discrete voltage samples, with the second and third voltage samples of the first group being the first and second samples of the second group. The controller estimates a steady-state voltage of the first and second voltages using the sample groups, prior to the first and second voltages converging on actual steady-state voltage values. The controller executes a corresponding control action when the steady-state voltage estimate is stable or unstable relative to a defined stability threshold.

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, a positive-electrode-side second resistor having one end grounded and another end, voltage of which being measured by the control unit, a negative-electrode-side second resistor having one end grounded, a positive-electrode-side C contact switch as a twin relay that alternatively 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, and a negative-electrode-side C contact switch as a twin relay that alternatively 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.

Apparatus (1) is for detecting electrical current in a support (2) for an overhead power line (3) adapted to carry AC electricity at a nominal frequency. The apparatus (I) comprises a first and a second electrical contact (16, 17). The first and second electrical contacts (16, 17) are adapted to be electrically coupled to the support (2) in spaced apart relationship, in use. A voltage detector (7) is coupled to the first and second contacts. A first voltage signal generator (11) is coupled to the first electrical contact (16) and is adapted to generate a voltage signal at a second frequency. A processor (15) is coupled to an output from the voltage detector (7). The voltage detector (7) is adapted to detect a first voltage differential between the first and second electrical contacts (16, I 7) at a first frequency corresponding to the nominal frequency, and to detect a second voltage differential between the two electrical contacts (16, 17) at the second frequency. The processor (15) receives the first and second voltage differentials, and the processor (15), dependant on the detected first and second voltage differentials, generates an output signal indicative of the presence of an electrical current in the support (2).

Methods and devices are provided for testing the function of a standard insulation monitoring device, installed in an ungrounded power supply system, during operation. The basic concept of the invention rests upon adding a testing apparatus to the ungrounded power supply system, which is being monitored using an insulation monitoring device according to regulations, between the active conductors of an ungrounded power supply system and ground, said testing apparatus systematically changing an insulation resistance of the ungrounded power supply system and observing the reaction of the insulation monitoring device in a fully automated manner in perpetually repetitive testing cycles. The power supply system is monitored perpetually during its operation. In the method, the current operating state (insulation level, load state) of the power supply system is detected via network parameters, such as insulation resistance and system leakage capacity, and consulted for assessing the functionality of the insulation monitoring device.

Methods and devices for insulation monitoring of an ungrounded IT power supply system having at least two phase conductors includes determining an insulation resistance separately for each phase conductor using a separate response value. In one embodiment of the invention, relevant current and voltage distributions are calculated. In another embodiment, a change time window is set within which a second response value is activated. In yet another embodiment, an option of shutting down/continuing operation of the IT power supply system is offered.