In described examples, a measurement circuit includes an isolated power supply that generates an output signal in response to an input signal. A signal processing circuit is coupled to the isolated power supply and generates a first signal in response to a sense signal. A load manipulator circuit is coupled to the signal processing circuit and the isolated power supply. The load manipulator circuit receives the first signal. A detect circuit is coupled to the isolated power supply and generates a second signal in response to the input signal.

In described examples, a measurement circuit includes an isolated power supply that generates an output signal in response to an input signal. A signal processing circuit is coupled to the isolated power supply and generates a first signal in response to a sense signal. A load manipulator circuit is coupled to the signal processing circuit and the isolated power supply. The load manipulator circuit receives the first signal. A detect circuit is coupled to the isolated power supply and generates a second signal in response to the input signal.

A motor-control device includes: a command generation unit; an operation detection unit; a drive control unit outputting a drive control signal, a speed signal, and a drive force signal; a current control unit outputting a drive current and the drive current detection value; a mechanical characteristic estimation unit outputting a mechanical characteristic estimation value; an integration unit outputting an integrated drive time or drive amount integrated value of a drive unit; a set period determination unit outputting a signal indicating a set period for a mechanical characteristic permissible threshold output unit; a mechanical characteristic permissible threshold output unit outputting a mechanical characteristic permissible threshold; and a mechanical characteristic abnormality detection unit detecting a mechanical characteristic abnormality.

A motor-control device includes: a command generation unit; an operation detection unit; a drive control unit outputting a drive control signal, a speed signal, and a drive force signal; a current control unit outputting a drive current and the drive current detection value; a mechanical characteristic estimation unit outputting a mechanical characteristic estimation value; an integration unit outputting an integrated drive time or drive amount integrated value of a drive unit; a set period determination unit outputting a signal indicating a set period for a mechanical characteristic permissible threshold output unit; a mechanical characteristic permissible threshold output unit outputting a mechanical characteristic permissible threshold; and a mechanical characteristic abnormality detection unit detecting a mechanical characteristic abnormality.

There is obtained an electric-power conversion apparatus that prevents it that the temperature of a semiconductor switching device reaches a breakage temperature and hence the semiconductor switching device is broken and that realizes continuity of driving. The electric-power conversion apparatus includes a temperature sensor that detects a temperature of semiconductor switching device, and a temperature rising rate determination unit that compares a predetermined first threshold value with a temperature rising rate calculated based on a temperature detection value detected by the temperature sensor and determines that the temperature rising rate has exceeded the first threshold value; when the temperature rising rate determination unit determines that the temperature rising rate has exceeded the first threshold value, protective operation for suppressing an output of an electric-power conversion unit is performed.

There is obtained an electric-power conversion apparatus that prevents it that the temperature of a semiconductor switching device reaches a breakage temperature and hence the semiconductor switching device is broken and that realizes continuity of driving. The electric-power conversion apparatus includes a temperature sensor that detects a temperature of semiconductor switching device, and a temperature rising rate determination unit that compares a predetermined first threshold value with a temperature rising rate calculated based on a temperature detection value detected by the temperature sensor and determines that the temperature rising rate has exceeded the first threshold value; when the temperature rising rate determination unit determines that the temperature rising rate has exceeded the first threshold value, protective operation for suppressing an output of an electric-power conversion unit is performed.

A semiconductor module includes: a switching device including a gate pad; an output unit including an output pad connected with the gate pad of the switching device through a wire and outputting a drive signal from the output pad to the switching device; a temperature protection circuit detecting temperature and performing protection operation; and a heat conduction pattern connected with the output pad, extending from the output pad toward the temperature protection circuit, and conducting heat generated at the switching device to the temperature protection circuit.

The invention relates to a method for operating an electric machine (6), and to a control device (10) that is configured to carry out the method. The method comprises a normal mode (ψ.sub.normal) and a special mode (ψ.sub.special) in dependence on a preset target value (M.sub.target), wherein the normal mode (ψ.sub.normal) comprises the steps of detecting an operating state, wherein, in the event that the detected operating state is a special state, the special mode (ψ.sub.special) is carried out. The special mode (ψ.sub.special) comprises the steps of modulating a cyclic value (M.sub.cysl) on the present target value (M.sub.target) and detecting the operating state, wherein, in the event that the operating state is a normal state, the normal mode (ψ.sub.normal) is carried out.

The invention relates to a method for operating an electric machine (6), and to a control device (10) that is configured to carry out the method. The method comprises a normal mode (ψ.sub.normal) and a special mode (ψ.sub.special) in dependence on a preset target value (M.sub.target), wherein the normal mode (ψ.sub.normal) comprises the steps of detecting an operating state, wherein, in the event that the detected operating state is a special state, the special mode (ψ.sub.special) is carried out. The special mode (ψ.sub.special) comprises the steps of modulating a cyclic value (M.sub.cysl) on the present target value (M.sub.target) and detecting the operating state, wherein, in the event that the operating state is a normal state, the normal mode (ψ.sub.normal) is carried out.

A method of protecting a converter of a wind turbine and a respective protection system are provided. The converter is coupled to a generator of the wind turbine to perform conversion of electrical power produced by the generator, the converter including plural semiconductor components that are operational to provide the conversion of the electrical power. The method includes the performing of a step of estimating a junction temperature of at least one of the semiconductor components by determining a current in the converter associated with power loss in one or more of the semiconductor components; estimating power loss associated with the one or more semiconductor components based on the determined current and on a state of the one or more semiconductor components; and using a thermal model to estimate the junction temperature of the semiconductor components based on the estimated power loss. The estimating step is repeatedly performed.