The embodiments of the present disclosure disclose a relay holding circuit and a battery management system. the relay holding circuit may include: a high-voltage isolated power source, a power source driving module, and a microprocessor of a battery management system; the high-voltage isolated power source may be respectively connected to two electrodes of a battery pack, an output terminal of the power source driving module, the microprocessor, and a first terminal of a first switching device; an input terminal of the power source driving module may be connected to the microprocessor; the microprocessor may be further connected to a primary battery, the microprocessor may output a low-level signal to the power source driving module when the primary battery supplies power abnormally.

A point-on-wave relay device includes a first contact relay and a second contact relay in series with the first contact relay. A first state of the first contact relay in conjunction with a first state of the second contact relay causes a point-on-wave open operation and second state of the first contact relay in conjunction with a second state of the second contact relay causes a point-on-wave close operation.

A point-on-wave relay device includes a first contact relay and a second contact relay in series with the first contact relay. A first state of the first contact relay in conjunction with a first state of the second contact relay causes a point-on-wave open operation and second state of the first contact relay in conjunction with a second state of the second contact relay causes a point-on-wave close operation.

Disclosures of the present invention describe a switch device has a controlling and processing unit comprising a first zero point detector, a second zero point detector, an arc detector, and a microcontroller. According to zero crossing point of input voltage signal, zero crossing point of output voltage signal, relay's delay time, and arc-spark-induced signal, the microcontroller is capable of adaptively generating a relay controlling signal to control the relay, such that the relay achieves a short-circuit switching at the zero cross point of output voltage signal for making the output voltage signal be transmitted to at least one load device. Moreover, the microcontroller is also able to control the relay to finish a short-circuit switching at the zero cross point of input voltage signal, so as to stop the output voltage signal from being transmitted to the load device.

Disclosures of the present invention describe a switch device has a controlling and processing unit comprising a first zero point detector, a second zero point detector, an arc detector, and a microcontroller. According to zero crossing point of input voltage signal, zero crossing point of output voltage signal, relay's delay time, and arc-spark-induced signal, the microcontroller is capable of adaptively generating a relay controlling signal to control the relay, such that the relay achieves a short-circuit switching at the zero cross point of output voltage signal for making the output voltage signal be transmitted to at least one load device. Moreover, the microcontroller is also able to control the relay to finish a short-circuit switching at the zero cross point of input voltage signal, so as to stop the output voltage signal from being transmitted to the load device.

A fault monitoring system detects connectivity faults in a device control centre. The fault monitoring system includes, for the or each control section, at least a first pair of temperature sensors adapted to detect the temperature of a first pair of terminals (T.sub.L1-IN), (T.sub.L1-OUT). The system includes a processor configured to receive the detected temperatures, calculate an IN-OUT difference, the IN-OUT difference being a difference between the temperatures of the first pair of terminals (T.sub.L1), compare the calculated IN-OUT difference with a predetermined threshold value (T*.sub.L1), whereby a calculated difference IN-OUT (T.sub.L1), greater than the predetermined threshold value (T*.sub.L1), is indicative of a connectivity fault at one of the first pair of terminals, and to generate at least one output signal based on the results of the comparison.

A fault monitoring system detects connectivity faults in a device control centre. The fault monitoring system includes, for the or each control section, at least a first pair of temperature sensors adapted to detect the temperature of a first pair of terminals (T.sub.L1-IN), (T.sub.L1-OUT). The system includes a processor configured to receive the detected temperatures, calculate an IN-OUT difference, the IN-OUT difference being a difference between the temperatures of the first pair of terminals (T.sub.L1), compare the calculated IN-OUT difference with a predetermined threshold value (T*.sub.L1), whereby a calculated difference IN-OUT (T.sub.L1), greater than the predetermined threshold value (T*.sub.L1), is indicative of a connectivity fault at one of the first pair of terminals, and to generate at least one output signal based on the results of the comparison.

Provided are embodiments for a circuit for a relay drive with a power supply economizer. The circuit includes a relay having a relay coil and a relay contact. The circuit also includes a power source to generate power for a coil drive voltage to operate the relay, and a controller configured to provide a command signal to operate the circuit in a plurality of modes. The circuit includes a first gate drive coupled to a first switch, wherein the first switch connects the relay coil to the circuit, and a second gate drive coupled to a second switch, wherein the second switch changes an effective resistance of a resistor network of the circuit to modify the coil drive voltage. Also provided are embodiments for a method for operating a circuit including relay drive with a power supply economizer.

Provided are embodiments for a circuit for a relay drive with a power supply economizer. The circuit includes a relay having a relay coil and a relay contact. The circuit also includes a power source to generate power for a coil drive voltage to operate the relay, and a controller configured to provide a command signal to operate the circuit in a plurality of modes. The circuit includes a first gate drive coupled to a first switch, wherein the first switch connects the relay coil to the circuit, and a second gate drive coupled to a second switch, wherein the second switch changes an effective resistance of a resistor network of the circuit to modify the coil drive voltage. Also provided are embodiments for a method for operating a circuit including relay drive with a power supply economizer.

The embodiments of the present disclosure disclose a relay holding circuit and a battery management system. the relay holding circuit may include: a high-voltage isolated power source, a power source driving module, and a microprocessor of a battery management system; the high-voltage isolated power source may be respectively connected to two electrodes of a battery pack, an output terminal of the power source driving module, the microprocessor, and a first terminal of a first switching device; an input terminal of the power source driving module may be connected to the microprocessor; the microprocessor may be further connected to a primary battery, the microprocessor may output a low-level signal to the power source driving module when the primary battery supplies power abnormally.