Passive filters, line replaceable units and a modular power supply are provided. The passive filter comprises an inductor and a diode bridge. The inductor has a first end and a second end. The first end is coupleable to a phase output of an inverter. The diode bridge comprises a first diode and a second diode. The anode of the first diode is coupled to the second end of the inductor and a cathode of the first diode is coupleable to a positive DC bus voltage. The cathode of the second diode is coupled to the second end of the inductor and the anode of the second diode is coupleable to a negative DC bus voltage. The passive filter output is coupleable to cable(s) for an AC electric machine. A reverse recovery charge of the diodes achieves a target DV/DT for an output voltage of the passive filter at operating temperatures.

A multi-level boost apparatus. Voltage allocation among N first switches is achieved by connecting N voltage dividing modules, sequentially connected in series, in parallel with the N first voltage switches, respectively. Thereby, a voltage across each of the N first switches is within a safety range. Even if an input voltage is high and a voltage across a flying capacitor is zero at an instant of being powered, it is prevented that a second one to an N-th one of the N first switches break down due to overvoltage.

A snubber device to be mounted to a terminal of a semiconductor module is provided. The snubber device includes n (n: integer of 1 or greater) parallel charge paths each having a positive-side capacitor, a first diode, and a negative-side capacitor sequentially connected in series between positive-side and negative-side terminals of the semiconductor module, and configured to enable current to flow from the positive-side terminal toward the negative-side terminal; and (n+1) parallel discharge paths each of which having a second diode connected between the negative-side terminal or the negative-side capacitor of an N.sup.th charge path (N: integer within a range of 0≤N≤n) of then charge paths and the positive-side capacitor of a (N+1).sup.th charge path of the n charge paths or the positive-side terminal, and configured to enable current to flow from the negative-side terminal toward the positive-side terminal via at least one of the negative-side and positive-side capacitors.

A buffer circuit coupled in parallel to a rectifier circuit in a secondary side of a flyback converter, the buffer circuit including: a capacitive element configured to be charged by an output capacitor when a primary power switch in the flyback converter is turned on; and the capacitive element being configured to be discharged through a secondary winding of a transformer when the primary power switch is turned off, in order to reduce energy stored in a primary leakage inductor in a primary side of the flyback converter, whereby a spike voltage generated in a secondary leakage inductor in the secondary side is reduced, and efficiency of the flyback converter is improved.

The connection distance between a first snubber circuit and the positive electrode of a first semiconductor element is shorter than the connection distance between the first snubber circuit and the positive electrode of a third semiconductor element. The connection distance between the first snubber circuit and the negative electrode of a fourth semiconductor element is shorter than the connection distance between the first snubber circuit and the negative electrode of a second semiconductor element. The connection distance between a second snubber circuit and the positive electrode of the third semiconductor element is shorter than the wiring distance between the second snubber circuit and the positive electrode of the first semiconductor element, and the connection distance between the second snubber circuit and the negative electrode of the second semiconductor element is shorter than the wiring distance between the second snubber circuit and the negative electrode of the fourth semiconductor element.

A first capacitor is connected between a first connection point and a second connection point. A second capacitor is connected between a third connection point and a fourth connection point. A current sensor is provided between the first connection point and the third connection point. A sum of the third wiring length which is a length of wiring from the first connection point to the third connection point and the fourth wiring length which is a length of wiring from the second connection point to the fourth connection point is smaller than a sum of the first wiring length which is a length of wiring from a first input terminal to the first connection point and the second wiring length which is a length of wiring from a second input terminal to the second connection point.

A power source device includes a transformer, a rectifying circuit, a series circuit, a switching element and a capacitor. The transformer includes first and second primary windings and a secondary winding. The rectifying circuit includes first and second output terminals and fully rectifies an AC voltage. The series circuit in which an inductor and a rectifying element are connected in series and connected between the first output terminal and a connecting point where one end of the first primary winding and one end of the second primary terminal are connected. The switching element is connected between the other end of the second primary winding and the second output terminal and switched between an on state and an off state. The capacitor is connected between the other end of the first primary winding and the second output terminal. An inductance of the inductor is set so that a voltage of the capacitor is higher than an output voltage of the rectifying circuit.

The invention describes a system (100) for transferring electrical power to an electrical load (110), comprising: a direct electrical voltage source (105), and at least one wave generator (145) adapted for converting the direct electric voltage into voltage waves to be transmitted to the electrical load (110); wherein said wave generator (145) comprises at least: an active switch (180) provided with two connection terminals (185, 190) and adapted for being controlled by an electric control signal between a saturation condition, in which it allows the passage of electrical current between said connection terminals (185, 190), and a prevention condition, in which it prevents said passage of electrical current, and a resonant circuit (200) sized to reduce the electrical power applied to said active switch (180) in the moments in which said active switch switches from the saturation condition to the prevention condition and vice-versa; and wherein said resonant circuit (200) comprises at least: a central electrical node (215) to which a first connection terminal (185) of the active switch (180) is connected, a first electrical branch (205) extending between said central electrical node (215) and a first terminal (210), a second electrical branch (220) extending between said central electrical node (215) and the first terminal (210) or between said central electrical node (215) and a further terminal (235) connected to a reference voltage, a resonance inductance (225) arranged on the first electrical branch (205), and a resonance capacity (230) arranged on the second electrical branch (220).

A voltage converter comprising a voltage input, a transformer comprising a primary winding coupled with the voltage input, a main switch coupled at a node with the primary winding, a snubber circuit coupled with the voltage input and with the node, the snubber circuit comprising a controllable switch having a gate and a source. A control circuit is coupled with the main switch and configured to turn the main switch on and off to convert an input voltage supplied to the voltage input to an output voltage distinct from the input voltage. The gate is coupled with the source to prevent the controllable switch from turning on.

The present invention is a power module for a system for converting a direct electrical power into a three-phase electrical power. The power module according to the invention comprises two inputs (E1, E2), an output (S), two switches (1), two diodes (D), and two capacitors (Cs, Cov) and to a conversion system comprising such a power module.