An improved system for measuring current within a power semiconductor module is disclosed, where the system is integrated within the power module. The system includes a point field detector sensing a magnetic field resulting from current flowing in one phase of the module. A lead frame conductor may be provided to shape the magnetic field and minimize the influence of cross-coupled magnetic fields from currents conducted in other power semiconductor devices within one phase of the module. Optionally, a second point field detector may be provided at a second location within the module to sense a magnetic field resulting from the current flowing in the same phase of the module. Each phase of the power module includes at least one point field detector. A decoupling circuit is provided to decouple multiple currents flowing within the same phase or to decouple currents flowing within different phases of the power module.

An improved system for measuring current within a power semiconductor module is disclosed, where the system is integrated within the power module. The system includes a point field detector sensing a magnetic field resulting from current flowing in one phase of the module. A lead frame conductor may be provided to shape the magnetic field and minimize the influence of cross-coupled magnetic fields from currents conducted in other power semiconductor devices within one phase of the module. Optionally, a second point field detector may be provided at a second location within the module to sense a magnetic field resulting from the current flowing in the same phase of the module. Each phase of the power module includes at least one point field detector. A decoupling circuit is provided to decouple multiple currents flowing within the same phase or to decouple currents flowing within different phases of the power module.

The present invention discloses a DC converter valve state detection method based on temporal features of converter terminal currents, including the following steps: collecting three-phase AC currents on a converter valve-side of a DC transmission system; defining a current when the currents of two commutating valves are equal as a base value, greater than the base value as a valve conducting current, and less than the base value as a valve blocking current; constructing a valve conducting state by a relative relationship among amplitudes of the three-phase AC currents, and calculating a time interval of each valve conducting state; comparing time intervals of 6 valve conducting states with a time interval of a valve conducting state in normal operation, and determining whether the 6 valve states are normal according to the result of comparison and locating all abnormal valves. The present invention can reliably detect valve states and locate abnormal valves through sequence detection. This method can be applied to actual fault phase judgment and commutation failure judgment, providing a good support for accurate judgment of DC control and protection.

Arrangements and methods for identifying a phase-to-ground inverter short circuit in an IT (isolé-terre or isolated ground) network are provided. In the method, AC current values of all three phases and DC current values are measured and evaluated at a frequency that is higher than the clock frequency of the inverter. An AC short-circuit current is also identified by subtracting the fundamental wave from the AC current sensor values. An AC component of the DC current sensor value is also identified, and it is identified whether this component is higher than a value predefined for regular operation. The AC short-circuit current and the AC component of the DC current sensor value are also compared. A short circuit is identified for the phase if the two values of the AC short-circuit current and the AC component of the DC current sensor value are approximately equal.

Arrangements and methods for identifying a phase-to-ground inverter short circuit in an IT (isolé-terre or isolated ground) network are provided. In the method, AC current values of all three phases and DC current values are measured and evaluated at a frequency that is higher than the clock frequency of the inverter. An AC short-circuit current is also identified by subtracting the fundamental wave from the AC current sensor values. An AC component of the DC current sensor value is also identified, and it is identified whether this component is higher than a value predefined for regular operation. The AC short-circuit current and the AC component of the DC current sensor value are also compared. A short circuit is identified for the phase if the two values of the AC short-circuit current and the AC component of the DC current sensor value are approximately equal.

An abnormality diagnosis system performs an abnormality diagnosis of a plurality of motor systems that include a motor for moving a moving body. The abnormality diagnosis system identifies a comparison target system that is the motor system, among the motor systems, that is a comparison target in relation to a diagnosis target system that is the motor system to be a target of the abnormality diagnosis. The abnormality diagnosis system acquires a state-related value that is a value related to an operation state of the motor from each of the diagnosis target system and the comparison target system. The abnormality diagnosis system performs a comparison of the state-related value that is acquired from the diagnosis target system and the state-related value that is acquired from the comparison target system, and diagnoses a presence or absence of an abnormality in the diagnosis target system using a result of the comparison.

An abnormality detection method according to one aspect of the present disclosure is a method of detecting an abnormality in an AC signal to be input from an AC power supply. The method includes, where an ideal AC signal is represented as V.sub.0 sin ωt (V.sub.0: amplitude, co: angular frequency, t: time), calculating an arithmetic value including a value represented by sin.sup.2ωt+cos.sup.2ωt and determining that the AC signal is abnormal when the arithmetic value is out of a threshold range.

An abnormality detection method according to one aspect of the present disclosure is a method of detecting an abnormality in an AC signal to be input from an AC power supply. The method includes, where an ideal AC signal is represented as V.sub.0 sin ωt (V.sub.0: amplitude, co: angular frequency, t: time), calculating an arithmetic value including a value represented by sin.sup.2ωt+cos.sup.2ωt and determining that the AC signal is abnormal when the arithmetic value is out of a threshold range.

An apparatus and methods to operate the same to provide fast fault-detection on power semiconductor devices such as power transistors are disclosed. In some embodiment, a desaturation based fault-detection circuit for a power transistor is provided. The fault-detection circuit has an adaptable blanking time and a disconnect switch in the blanking mechanism that allow for quick enabling of fault-detection mechanisms to achieve fast fault detection times on power semiconductor devices.

A method determines a current flowing through at least one switching element of an electrical circuit arrangement. When the switching element is turned on the current flows through a switchable portion of the switching element. The switching element is associated with a temperature sensor and a voltage sensor. The temperature sensor measures a temperature of the switching element and the voltage sensor measures a voltage drop across the switchable portion of the switching element. The temperature sensor and the voltage sensor are connected to a computing device. The computing device determines a current value of the current based on the measured temperature and the measured voltage drop.