POWER SURGE PROPAGATION PROTECTION ELECTRICAL CONVERTER

Abstract

This electrical converter (104) comprises: - an inverter (106) designed to provide at least one alternating voltage, referred to as the input voltage (VX, VY, VZ), from a direct current voltage, referred to as the input voltage (VE); - an AC-AC voltage converter designed to provide an alternating voltage, referred to as the output voltage (VAC), from the alternating input voltage(s) (VX, VY, VZ), such that the alternating output voltage (VAC) has an amplitude dependent on a frequency F of the alternating input voltage(s) (VX, VY, VZ); and - a rectifier (118) designed to provide a direct current voltage, referred to as the output voltage (VS), from the alternating output voltage (VAC). Figure for the abbreviation: Fig. 1

Description

Description Title of the invention: ANTI-ELECTRICAL CONVERTER POWER SURGE PROPAGATION Technical field of the invention

[0001] — The present invention relates to an anti-propagation electrical converter overvoltage. Technological background

[0002] — The prior art of DC-DC electrical converters is known with galvanic isolation, such as for example the front converter (from English "Forward converter"). In this type of electrical converter, a switch com- The controllable connects and disconnects, alternately, a DC voltage source of a transformer's primary winding. When connected to the primary, the The voltage source charges the transformer. When the DC voltage source is When disconnected, the transformer discharges through a secondary winding into a A capacity designed to present a continuous output voltage. A device of The control is designed to regulate the DC output voltage by adjusting a ratio cyclic opening / closing of the switch.

[0003] — In the event of a failure of the electrical converter, there is a risk of propagation of the DC input voltage to the output of the power converter, so that the The DC output voltage can become very high. In the case where the converter Electricity is used in an aircraft to power equipment critical for flight. The propagation of the power surge can damage equipment and lead to a catastrophic situation for the aircraft.

[0004] It may therefore be desirable to provide an electrical converter that allows for to overcome at least some of the aforementioned problems and constraints. Summary of the invention

[0005] TI is therefore proposed an electrical converter, characterized in that it comprises: an inverter designed to provide at least one alternating voltage, known as an input voltage from a direct current voltage called the input voltage; an AC-AC voltage converter designed to provide a voltage alternative output voltage(s) from the alternating input voltage(s), of so that the alternating output voltage has a dependent amplitude of a frequency F of the alternating input voltage(s); and a rectifier designed to provide a so-called DC output voltage from the alternating output voltage.

[0006] — Optionally, the AC-AC voltage converter includes: an electric motor designed to provide rotational mechanical energy to starting from the alternating input voltages; and an electric generator designed to supply an alternating voltage known as output from the mechanical energy of rotation. Optionally, the electric motor is also a permanent magnet synchronous motor. Optionally, the electric motor and the electric generator also share a common ferromagnetic core. Optionally, the inverter also includes at least two switching arms designed to receive the DC input voltage and each having two switches connected to each other at a midpoint, the AC input voltage(s) being supplied respectively between the pair(s) of midpoints. Optionally, the inverter also includes a control device designed to control the switching arms independently of the DC output voltage. An electrical installation is also proposed, including: an electrical converter according to the invention; and a DC voltage source designed to provide DC voltage entry. Optionally, the electrical installation also includes an aircraft computer designed to be powered by the DC output voltage. An aircraft comprising an electrical installation according to the invention is also proposed. Brief description of the figures The invention will be better understood with the aid of the following description, given solely by way of example and made with reference to the single attached figure: Figure 1 is an electrical diagram of an example of an electrical installation in in which the invention is implemented. Detailed description of the invention With reference to [Fig.1], an example of an electrical installation 100 intended to equip an aircraft and in which the invention is implemented, will now be described. The electrical installation 100 includes, firstly, a DC voltage source 102 designed to provide a DC input voltage VE. The DC voltage source 102 may include, for example, one or more batteries. The DC input voltage VE is preferably greater than 100 V, and is, for example, 270 V, 600 V, or 800 V. The electrical installation 100 also includes an electrical converter 104 designed to convert the input DC voltage VE into a DC output voltage VS, preferably lower than the input DC voltage VE. For example, the output DC voltage is 28 V. Thus, the electrical converter 104 is a DC-DC converter. The electrical converter 104 includes, firstly, an inverter 106 designed to provide alternating input voltages, referred to as VX, VY, and VZ, from the direct current input voltage VE. In the example described, the inverter 106 is designed to provide three alternating input voltages, VX, VY, and VZ, with a relative phase shift of 120°, thus forming a three-phase voltage system. The alternating input voltages VX, VY, and VZ also have a frequency F that can vary, as will be described later. In the example described, the inverter 106 has several switching arms, each designed to receive the input DC voltage VE. Each switching arm has a so-called high-side switch and a so-called low-side switch, connected to each other at a midpoint. The high-side and / or low-side switch is controllable. Each switch is, for example, a semiconductor switch, such as a transistor switch like a MOSFET or an IGBT. The alternating input voltages VX, VY, VZ are then respectively supplied between the pairs of midpoints, as illustrated in [Fig.1], and alternately equal the DC input voltage VE and its opposite. The inverter 106 further includes a switching arm control device 107. The control device 107 is designed to switch the switching arms at a predefined switching frequency and according to a duty cycle that changes over time and repeats according to the frequency F. The control device 107 is designed to change the duty cycle in open loop, that is, independently of the DC output voltage VS or, more generally, of any electrical quantity located downstream of a galvanic isolation barrier 116 which will be described later. The electrical converter 104 further includes an electric motor 108 designed to provide rotational mechanical energy E from the alternating input voltages VX, VY, VZ. For example, the electric motor 108 has stator phases (three in the example described, respectively designated by the references X, Y, and Z) designed to receive the alternating input voltages VX, VY, and VZ, respectively. In response to the alternating input voltages VX, VY, and VZ, the stator phases are designed to generate a rotating magnetic field that drives a rotor 110 of the electric motor 108 to rotate at a frequency-dependent speed F. The rotor 110 thus provides the rotational mechanical energy E. Preferably, the electric motor 108 is a synchronous motor. Thus, the rotor 110 has a rotational speed V proportional to the frequency F. Preferably, the motor 108 is a permanent magnet motor on the rotor 110. Thus, a rotor magnetic field of known value is easily generated by the permanent magnets and can interact with the stator magnetic field to rotate the rotor 110. Since the rotor magnetic field is known, it does not need to be controlled, which simplifies the control of the electric motor 108. The electrical converter 104 further includes an electrical generator 112 designed to provide an alternating current output voltage VAC from the mechanical rotational energy E. In the example described, the electrical generator 112 has a stator phase 114 relative to which the rotor 110 rotates, thereby generating the alternating current output voltage VAC in the stator phase 114. In this way, the amplitude of the alternating current output voltage VAC depends on the rotational speed of the rotor 110 and thus on the frequency F of the input alternating current voltage(s) VX, VY, VZ. Furthermore, the amplitude of the alternating current output voltage VAC is independent of the amplitudes of the input alternating current voltages VX, VY, VZ. In [Fig. 1], the electrical machines 108 and 112 are shown as separate, but in practice they could be grouped together. In this case, the stator phases X, Y, Z and 114 could be mounted on the same ferromagnetic core. By passing through the mechanical energy E, a very strong galvanic isolation barrier 116 is obtained. The electric motor 108 followed by the electric generator 112 thus form an AC-AC voltage converter designed to provide an AC output voltage from the AC input voltage(s), so that the AC output voltage has an amplitude dependent on a frequency F of the AC input voltage(s), but independent of an amplitude of each AC input voltage. The electrical converter 104 further includes a rectifier 118 designed to provide the DC output voltage VS from the AC output voltage VAC. For example, as illustrated in [Fig.1], the rectifier 118 may include a full diode bridge followed by a voltage smoothing capacitor, with the DC output voltage VS being supplied across the smoothing capacitor. The electrical installation 100 further includes a bus 122 designed to receive the DC output voltage VS, and one or more aircraft equipment (collectively designated by reference 124) connected to the bus 122 to receive the DC output voltage VS for their power supply. Equipment 124 connected to bus 122 is preferably equipment critical for the aircraft, such as an aircraft computer such as a so-called mission computer which enables the pilotability of the aircraft or an avionics computer which transmits all the status information of the aircraft systems throughout the flight. In the event of an overvoltage causing a significant increase in the DC input voltage VE, this results in an increase in the AC input voltages VX, VY, VZ but not in their frequency F, so that the DC output voltage VS remains unchanged. This overvoltage cannot reach the equipment 124 via the control device 107 because the latter is located upstream of the galvanic isolation barrier 116, without connection with the downstream due to its open-loop operation. It is clear that an electrical converter such as the one described above makes it possible to avoid the propagation of an overvoltage which could be damaging to downstream equipment powered by the electrical converter. It should also be noted that the invention is not limited to the embodiments described above. Indeed, it will be apparent to those skilled in the art that various modifications can be made to the embodiments described above, in light of the information just disclosed to them. In the detailed presentation of the invention given above, the terms used should not be interpreted as limiting the invention to the embodiments set forth in this description, but should be interpreted to include all equivalents which can be foreseen by a person skilled in the art by applying their general knowledge to the implementation of the teaching which has just been disclosed to them.

Claims

Demands

1. Electrical converter (104), characterized in that it comprises: an inverter (106) designed to provide at least one voltage al- alternative input (VX, VY, VZ) from a voltage continuous input (VE); an AC-AC voltage converter designed for to provide an alternating voltage, known as the output voltage (VAC), from the alternating input voltage(s) (VX, VY, VZ), so that the alternating output voltage (VAC) exhibits a amplitude depending on a frequency F of the voltage(s) input alternatives (VX, VY, VZ); and a rectifier (118) designed to provide a direct voltage output voltage (VS) from the output alternating voltage (VAC).

2. Electrical converter (104) according to claim 1, wherein the AC-AC voltage converter includes: an electric motor (108) designed to supply power rotational mechanics (E) from alternating voltages input (VX, VY, VZ); and an electric generator (112) designed to supply a voltage alternative output (VAC) from the energy rotational mechanics (E).

3. Electrical converter (104) according to claim 2, wherein the The electric motor (108) is a permanent magnet synchronous motor.

4. An electrical converter (104) according to claim 1 or 2, wherein the electric motor (108) and the electric generator (112) include a common ferromagnetic core.

5. Electrical converter (104) according to any one of the following claims indications 1 to 4, in which the inverter (106) comprises at least two switching arms designed to each receive the DC voltage input (VE) and each featuring two switches connected to one another the other at a midpoint, the alternating input voltage(s) (VX, VY, VZ) being respectively provided between the pair or pairs of points environments.

6. Electrical converter (104) according to claims 1 to 5, wherein the inverter (106) further comprises a control device (107) designed to control the switching arms independently of the DC output voltage (VS).

7. Electrical installation (100) comprising: an electrical converter (104) according to any one of the claims 1 to 6; and a DC voltage source (102) designed to supply the DC input voltage (VE).

8. Electrical installation (100) according to claim 7, comprising in in addition to an aircraft computer designed to be powered by the voltage continuous output (VS).

9. Aircraft comprising an electrical installation (100) according to claim- indication 7 or 8.