A rectifying bridge has a thyristor coupled in series with a rectifying element between a first rectified output terminal of a rectifying bridge circuit and a second rectified output terminal of the rectifying bridge circuit. A diode is coupled in series with a DC voltage source between a gate of the thyristor and the second rectified output terminal.

A power conversion system includes an uninterruptible power apparatus, a generator module, and a control unit. The uninterruptible power apparatus includes a conversion module and a DC-to-AC conversion unit. The control unit controls the conversion module and the generator module according a power command so that a first average power provided from a DC power source coupled to the conversion module is slowly increased or decreased, and the control unit controls the conversion module according to a bus voltage so that a second average power provided from a mains is slowly decreased or increased corresponding to the first average power.

A method for detecting an error in a generator unit which has an electric machine (100) with a rotor winding (110) and a stator winding (120) and a rectifier (130) connected thereto, via which rectifier the electric machine (100) is connected to an electrical system (150) of a motor vehicle, the excitation current (IE) flowing through the rotor winding (110) of the electric machine (100) being plotted and it being concluded that there is an error in the generator unit depending on whether a frequency component (A) of a frequency spectrum of the plot of the excitation current (IE) in a frequency range above a lower speed limit (SW) is larger than a threshold value (S).

A method for detecting an error in a generator unit which has an electric machine (100) with a rotor winding (110) and a stator winding (120) and a rectifier (130) connected thereto, via which rectifier the electric machine (100) is connected to an electrical system (150) of a motor vehicle, the excitation current (IE) flowing through the rotor winding (110) of the electric machine (100) being plotted and it being concluded that there is an error in the generator unit depending on whether a frequency component (A) of a frequency spectrum of the plot of the excitation current (IE) in a frequency range above a lower speed limit (SW) is larger than a threshold value (S).

A method for operating a power converter is described. The power converter includes three input nodes each configured to receive a respective one of three input voltages, two DC link nodes configured to provide a DC link voltage, and a midpoint coupled to each DC link node. Three inductors are each connected to a respective one of the three input nodes. A rectifier bridge including three bridge legs are each coupled to a respective one of the three inputs through a respective one of the three inductors and connected to the respective one of the three inductors at a respective switch node. Each bridge leg is connected to the two DC link nodes and the midpoint, and includes at least one electronic switch. The power converter is operated in a reduced switching mode by deactivating at least one of the three bridge legs for a predefined time period.

A selection circuit generates a voltage V.sub.S of a switching terminal VS or a power supply voltage V.sub.CC, whichever is higher, in a common line. A regulator stabilizes a voltage V.sub.COML of a reference line at a level lower than a voltage V.sub.COM of the common line by a predetermined voltage difference V. A charge pump circuit is provided between the common line and the reference line and steps up a voltage difference V between the common line and the reference line. A rectifying element charges a bootstrap capacitor between a bootstrap terminal and the switching terminal, with an output voltage of the charge pump circuit.

A converter cell includes a first terminal; a second terminal; a plurality of switching elements provided with respective gate units; an energy storage element; an clamp inductor provided to restrict a rate of change of current from the energy storage element to the switching elements; and a first energy converter provided in parallel to the clamp inductor. The first energy converter is provided to power the gate units by utilising energy from the clamp inductor when the converter cell changes state to be in a short circuit state.

A converter cell includes a first terminal; a second terminal; a plurality of switching elements provided with respective gate units; an energy storage element; an clamp inductor provided to restrict a rate of change of current from the energy storage element to the switching elements; and a first energy converter provided in parallel to the clamp inductor. The first energy converter is provided to power the gate units by utilising energy from the clamp inductor when the converter cell changes state to be in a short circuit state.

In accordance with an example embodiment, an isolation circuit for electrically isolating a first circuit operating at a first voltage from a second circuit operating at a second voltage that is different than the first voltage is provided. The isolation circuit comprises: a first voltage source that operates at the first voltage, the first voltage source having a first supply rail and a second supply rail; an isolation device having a first input, a second input, a first output and a second output, the second input coupled to a first ground potential and the second output coupled to a second ground potential that is electrically isolated from the first ground potential by the isolation device; a first resistor coupled between the first supply rail and the first input of the isolation device; a second resistor coupled to the first input of the isolation device and the second input of the isolation device; and wherein the first output of the isolation device is coupled to the second circuit.

In accordance with an example embodiment, an isolation circuit for electrically isolating a first circuit operating at a first voltage from a second circuit operating at a second voltage that is different than the first voltage is provided. The isolation circuit comprises: a first voltage source that operates at the first voltage, the first voltage source having a first supply rail and a second supply rail; an isolation device having a first input, a second input, a first output and a second output, the second input coupled to a first ground potential and the second output coupled to a second ground potential that is electrically isolated from the first ground potential by the isolation device; a first resistor coupled between the first supply rail and the first input of the isolation device; a second resistor coupled to the first input of the isolation device and the second input of the isolation device; and wherein the first output of the isolation device is coupled to the second circuit.