Power supply for a bearing controller

Abstract

Power supply system for a magnetic bearing controller of a permanent magnet synchronous motor comprising: - a first power supply module, configured to be connected to an electrical network and to supply voltage to the magnetic bearing controller, - a second power supply module configured to supply voltage to the magnetic bearing controller, the voltage of the second power supply module being derived from the synchronous motor, - a device for selecting the first or second power supply module to supply voltage to the magnetic bearing controller, wherein the second power supply module is configured to provide, under nominal operating conditions, a voltage lower than the voltage supplied by the first power supply module, the second power supply module being mounted in parallel with the first power supply module and upstream of the magnetic bearing controller.The selection device is configured to select the power supply module providing the highest voltage to the magnetic bearing controller. Figure to be published with the abbreviation: Fig. 1,

Description

Title of the invention: Power supply for a bearing controller FIELD OF THE INVENTION

[0001] The invention relates to a power supply system comprising a first power supply module and a second emergency power supply module for powering a magnetic bearing controller of a permanent magnet synchronous motor. More particularly, the second power supply module powers the magnetic bearing controller by tapping. STATE OF THE ART

[0002] Traditionally, it is known to continuously power a magnetic bearing controller of a permanent magnet synchronous motor. The loss of power to the magnetic bearings is managed by means of ball bearings whose role is to support the shaft of the rotating machine in the event of a failure of the power supply to the magnetic bearings. These ball bearings are often unable to withstand one or more landings of the shaft when the magnetic bearings lose their electrical power supply: they may see their service life reduced, or be damaged.

[0003] In the case of a magnetic bearing controller being powered by a single power supply module, in the event of a power supply fault, the magnetic bearing controller is no longer functional. Then, the emergency ball bearing of the magnetic bearing, which is no longer controlled by the controller, risks being damaged following an unsupported stop of the motor and the freewheeling of the motor shaft. Thus, in the event of a power supply fault, the service life of the emergency bearings is greatly reduced.

[0004] To overcome this problem, it is known to use a second power supply module, this second power supply module constitutes a backup power supply module, in the event of a power failure of the magnetic bearing controller by the first power supply module.

[0005] Traditionally, a magnetic bearing controller of a permanent magnet synchronous motor is powered by a first power supply module, for operation in nominal mode (i.e. in normal operation of the first power supply module), and by a second emergency power supply module when a power supply fault occurs at the first power supply module.

[0006] It is known to use one or more batteries as a second power supply module.

[0007] However, the use of batteries presents several problems. First of all, batteries are bulky, which leads to significant space requirements. In addition, batteries have a significant weight.

[0008] Furthermore, batteries require a dedicated space for their installation, which must ensure ventilation taking into account their possible gas emissions, and the maintenance of an ambient temperature avoiding the risks of thermal runaway. Batteries require electronic charging devices which increase the cost of the solution and make it less flexible, because charged batteries become a prerequisite for the safe use of the rotating machine, while the charging device must also ensure that the batteries do not completely discharge, which would cause them to encounter a so-called deep discharge state, detrimental to their subsequent proper operation. Batteries therefore require regular maintenance and, having a limited lifespan, to be changed over time, which has an economic impact.

[0009] An aim of the present invention is to overcome all or part of the drawbacks of the prior art, in particular by making it possible to provide an emergency power supply to the magnetic bearing controller.

[0010] BRIEF DESCRIPTION OF THE INVENTION

[0011] To this end, the present invention relates to a power supply system for a magnetic bearing controller of a permanent magnet synchronous motor comprising: - a first power supply module, configured to be connected to an electrical network and to supply voltage to the magnetic bearing controller, - a second power supply module configured to supply voltage to the magnetic bearing controller, the voltage of the second power supply module being derived from the synchronous motor, - a device for selecting the first power supply module or the second power supply module for supplying voltage to the magnetic bearing controller, in which the second power supply module is configured to provide, in a nominal operating mode, a voltage lower than the voltage provided by the first power supply module, the second power supply module is mounted in parallel with the first power supply module and upstream of the magnetic bearing controller, the selection device is configured to select the power module providing the highest voltage to the magnetic bearing controller.

[0012] Advantageously, such a system makes it possible to provide emergency power to a magnetic bearing controller without requiring the use of consumable elements, requiring maintenance and replacements. A battery requires maintenance, must be replaced over time, while being bulky and heavy.

[0013] A power supply system according to the invention is simple, reliable, robust, maintenance-free and inexpensive.

[0014] By deriving the voltage from the synchronous motor, it is possible to supply voltage over a short period of time to the magnetic bearing controller without requiring a power supply module, independent of the first power supply module and the synchronous motor.

[0015] The second power supply module, drawing voltage from the synchronous motor, allows the magnetic bearing controller to be powered until the bearing's ball bearings, called "landers", can take over and receive the motor shaft of the synchronous motor at a speed low enough that the backup ball bearings never suffer premature wear or damage. The motor shaft lands on the bearing's ball bearings, until the final stop of the motor, without causing any damage to the bearing.

[0016] The power supply system according to the invention may also comprise one or more of the following characteristics considered individually or in all possible combinations: - the selection device comprises a voltage rectifying element; and / or - the second power supply module is configured to be supplied with voltage by the motor, at nominal operating speed; and / or - the second power supply module is configured to be supplied with voltage by the motor, when the motor is freewheeling, the motor acting as a generator; and / or - the second power supply module is configured to be supplied with voltage by the motor: - using a variable speed drive, in nominal operating mode, or - by the motor acting as a generator when it is freewheeling; and / or - the selection device comprises at least two OR-ing diodes, the first OR-ing diode is arranged downstream of the first power supply module, and the second OR-ing diode is arranged downstream of the second power supply module, - the first and second OR-ing diodes being arranged in parallel; and / or - the first power supply module and / or the second power supply module comprises a transformer; and / or - the voltage admitted by the magnetic bearing controller is between 70Vdc and 800Vdc, preferably between 100Vdc and 750Vdc; and / or - the second power supply module is configured to provide a minimum voltage of between 70Vdc and 120Vdc, preferably 100Vdc to the magnetic bearing controller at a frequency of between 60Hz and 100Hz, preferably 80Hz; and / or - the power supply system comprises a device for monitoring the voltage supplied by the power supply modules; and / or - the power supply system comprises, downstream of the first power supply module and the second power supply module, a capacitive filter smoothing the voltage; and / or - the capacitive filter forms an energy storage means.

[0017] The present invention also relates to a cycle gas compression system of a refrigeration and / or gas liquefaction system comprising a supply system according to one of the described embodiments.

[0018] The present invention also relates to a method for powering a magnetic bearing controller of a permanent magnet synchronous motor comprising a step of selecting by a selection device a power supply module providing the highest voltage for powering the magnetic bearing controller, the selection being made between: - a first power supply module, configured to be connected to an electrical network and to supply voltage to the magnetic bearing controller, and - a second power supply module, mounted in parallel with the first power supply module, the voltage supplied by the second power supply module being derived from the synchronous motor, the second power supply module providing, in a nominal operating mode, an electrical voltage lower than the voltage provided by the first power supply module, a power supply step in which the magnetic bearing controller is powered by the power module selected by the selection device.

[0019] Advantageously, such a power supply method makes it possible to maintain a voltage supply to the magnetic bearing controller and avoid damage to one of the bearings in the event of a lack of power supply to the magnetic bearing controller.

[0020] The second power supply module, drawing voltage from the synchronous motor, allows the magnetic bearing controller to be powered until the ball bearings of the bearing, called "landers", can take over and receive the motor shaft of the synchronous motor. The motor shaft lands on the ball bearings of the bearing, until the final stop of the motor, without causing any damage to the bearing.

[0021] The feeding method according to the invention may also comprise one or more of the following characteristics considered individually or in all possible combinations: - the synchronous motor acts as a generator when freewheeling; and / or - the second power supply module supplies power to the magnetic bearing controller for a period of time between 1s and 60s, more particularly between 5s and 30s; and / or - the second power supply module powers the magnetic bearing controller, the voltage supplied to the magnetic bearing controller reduces over time until it reaches a minimum voltage; and / or - the minimum voltage supplied to the magnetic bearing controller is between 70Vdc and 120Vdc and has a frequency between 60Hz and 100 Hz; and / or - after the power supply of the magnetic bearing controller by the second power supply module is followed by a rest period during which the magnetic bearing controller is not powered by the second power supply module; and / or - the rest period is between 30s and 160s, more particularly between 100s and 140s, and more precisely 120s. BRIEF DESCRIPTION OF THE FIGURES

[0022] Other characteristics and advantages of the present invention will appear on reading the description and the following figures:

[0023] - [Fig.l] is an electrical schematic representation of a power supply system according to one embodiment of the invention,

[0024] - [Fig.2] is a representation of the evolution of the voltage supplied by the first and the second power supply module when the first power supply module fails,

[0025] - [Fig.3] illustrates a graph of the variation of the power supply carried out by the second power supply module

[0026] - [Fig.4] illustrates a flowchart defining the feeding process according to the invention.

[0027] It should be noted that these drawings have no other purpose than to illustrate the text of the description and do not constitute in any way a limitation of the scope of the invention.

[0028] To clarify the terms “upstream” and “downstream” relating to the arrangement of electrical components, the arrangement of these components is defined according to the direction of the current.

[0029] For example, a second electrical element, arranged downstream of a first electrical element, is further from the positive terminal of the voltage supply module than the first element. DETAILED DESCRIPTION OF THE INVENTION

[0030] As shown in [Fig.l], the invention relates to an electrical circuit of a power supply system 100 configured to power a magnetic bearing controller 102 of a synchronous motor 106. The bearing controller 102 controls the voltage supply to the magnetic bearings 104.

[0031] The power supply system comprises a first power supply module 130 and a second power supply module 140. The power supply system 100 further comprises a selection device 108. The selection module selects the first or second power supply module 130, 140 to supply voltage to the magnetic bearing controller 102.

[0032] In one embodiment, the first power supply module 130 is three-phase.

[0033] In one embodiment, the second power supply module 140 is three-phase.

[0034] The first power supply module 130 is connected to an electrical network.

[0035] The second power supply module 140 is connected to the synchronous motor 106, and derives the voltage from said motor.

[0036] When the synchronous motor is operating normally, the second power supply module is powered by a speed variator 105. The speed variator 105 controls the rotation of the synchronous motor 106 by acting on the voltage and frequency of the electrical power supply. The power supply is supplied to the motor by the speed variator 105.

[0037] When the synchronous motor 106 is freewheeling, it acts as a generator and supplies voltage to the second power supply module.

[0038] The first power supply module 130 and the second power supply module 140 are electrically arranged in parallel in the electrical circuit of the power supply system 100, upstream of the magnetic bearing controller 102. That is to say, the first power supply module 130 and the second power supply module 140 can be electrically connected in parallel to the same terminal or input of the electrical circuit of the power supply system 100.

[0039] The second power supply module is configured to provide, in a nominal operating regime, a voltage lower than the voltage provided by the first power supply module.

[0040] The expression in “nominal operating mode” is to be contrasted with the expression “in degraded mode”, and corresponds to the normal operating mode of the power supply system 100, without failure of the first power supply module 130.

[0041] In nominal operating mode, the voltage supplied by the first power supply module 130 is greater than that supplied by the second power supply module 140.

[0042] The selection device 108 is configured to select, during a selection step S1, the power supply module 130, 140 which will supply voltage to the magnetic bearing controller 102, during the power supply step S2 ([Fig.4]). The power supply module 130, 140 providing the highest voltage is selected, during the selection step SI, by the selection device 108.

[0043] In one embodiment, the selection device 108 may comprise one or more electromechanical and / or electrical and / or semiconductor contacts.

[0044] In one embodiment, the selection device 108 may comprise a voltage rectifier element 108a, 108b in the first power supply module, respectively the second power supply module. Such a type of selection device makes it possible to carry out a passive selection of the highest voltage supplied by the first or the second power supply module.

[0045] In one embodiment, the selection device 108 may comprise first and second voltage rectifier elements 108a, 108b. The first voltage rectifier element 108a is disposed downstream of the first power supply module 130. The second voltage rectifier element 108b is disposed downstream of the second power supply module 140. The first and second rectifier elements are connected in parallel in the electrical circuit.

[0046] The voltage rectifier elements 108a, 108b make it possible to rectify an alternating voltage and make it continuous.

[0047] In one embodiment, the selection device 108 comprises two diodes 108c, 108d arranged respectively downstream of the two rectifier elements 108a, 108b. In a more particular embodiment, the diodes 108c, 108d are OR-ing diodes.

[0048] In one embodiment, the first power supply module and the second power supply module each respectively comprise a voltage transducer 108e, 108f located between the rectifier element 108a, 108b and the diode 108c, 108d.

[0049] The voltage Vcp admitted by the bearing controller 102 is between a voltage Vcp_min and a voltage Vcp_max.

[0050] For example, the voltage Vcp_min can be between 50Vdc and 120Vdc, preferably between 70Vdc and 100Vdc. In this example, the Vcp_max is between 750Vdc and 850Vdc, preferably between 750Vdc and 800Vdc.

[0051] In one example, the first power supply module 130 is powered by an electrical network. The voltage of the electrical network may for example be 400 Vac. The first power supply module 130 may not have a transformer. In the case where it is considered that the alternating voltage supplied by the electrical network varies by around ±20%. The voltage range Valiml supplied by the first power supply module 130 is then between a voltage Valiml_min and a voltage Valiml_max.

[0052] With reference to the previous example, the voltage range provided by the first power supply module 130 is between 300Vac and 500Vac, preferably 320Vac and 480Vac, when the power supply system is operating in nominal operating mode. That is to say in the absence of failure of the first module. 130 power supply.

[0053] In this same example, in nominal operating mode, for the same input voltage at the first voltage module 130, the voltage Valim2_nom supplied by the second power supply module 140, drawn from the synchronous motor 106 via the speed variator 105, is between a voltage Valim2_nom_min and a voltage Valim2_nom_max.

[0054] Valim 2 can be understood, for example, between OVac and 600Vac.

[0055] Furthermore, in degraded mode, when the first power supply module 130 experiences a failure, the voltage Valim2_deg supplied by the second power supply module 140, drawn from the synchronous motor 106 acting as a generator, is between a value Valim2_deg_min and Valim2_deg_max, where the value Valim2_deg_min is greater than the value of Valim2_nom_min. The minimum voltage Valim2_deg_min must be greater than 0 to allow the power supply of the bearing controller 102.

[0056] For example, the value of Valim2_deg_is between 100Vac and 600Vac.

[0057] In this way, the voltage Valim2_nom, Valim2_deg supplied by the second power supply module 140 reaches, in nominal or degraded operating mode, a maximum voltage Valim2_nom_max, Valim2_deg_max greater than the maximum voltage tolerated for the bearing controller 102 Vcp_max, for example 560Vac.

[0058] Furthermore, for operation in nominal operating mode (without failure of the first power supply module 130), the maximum voltage Valim2_nom_max supplied by the second power supply module 140 may be greater than the maximum alternating voltage Valiml_max supplied by the first power supply module 130. The selection device 108 would then select the second power supply module 140, as long as the voltage Valim2_nom drawn from the synchronous motor 106 is greater than the voltage Valiml supplied by the first power supply module 130.

[0059] This does not correspond to a preferred embodiment. Indeed, in nominal operating mode, it is desired that the voltage supply of the bearing controller 102 is carried out by the first power supply module 130, connected to the electrical network, rather than the second power supply module 140, acting as a backup power source, drawing the voltage from the synchronous motor 106.

[0060] In a preferred embodiment, at least the first power supply module 130 or the second power supply module 140 comprises a transformer 132, 142. Preferably, the first power supply module 130 and the second power supply module 140 respectively comprise a transformer 132, 142.

[0061] In one embodiment, the transformers 132, 142 are three-phase transformers.

[0062] In a preferred embodiment, the first power supply module 130 comprises a transformer 132, and the second power module comprises a transformer 142.

[0063] The transformer 132 has a transformation ratio between a minimum transformation value Tl_min and a maximum transformation value Tl_max.

[0064] For example, Tl_min is equal to 1.01, plus 1.015, and more particularly 1.1. For example, Tl_max is equal to 2, more particularly 1.5 and more particularly 1.3.

[0065] The transformer 132, having a transformation ratio greater than 1, makes it possible to increase the value range of Valiml. At the output of the transformer, the voltage ValimlT is between ValimlT_min and ValimlT_max. ValimlT_min is greater than Valiml_min, and ValimlT_max is greater than Valiml_max.

[0066] For example, for a transformation ratio between 1.1 and 1.3, and for a power supply voltage of the electrical network of 400Vac, the voltage ValimlT at the output of the transformer 132 supplied to the bearing controller 102 comprises a minimum voltage Valiml T_min between 420Vac and 460Vac and a maximum voltage ValimlT_max between 500Vac and 540Vac. The voltage ValimlT can in this embodiment oscillate between 350Vac and 560Vac, which corresponds to a direct voltage between 475Vdc and 750Vdc.

[0067] Consequently, in the previous example, the use of a transformer 132, having a transformation ratio greater than 1, in the first power supply module 130 makes it possible to raise the maximum voltage Valmil_max supplied by the first power supply module 130 up to 560Vac.

[0068] Advantageously, the transformation ratio of the transformer 132 is chosen so that, in nominal operating mode, the voltage supply ValimlT provided by the first power supply module 130 is always greater than that provided by the second power supply module 140 (as illustrated in [Fig.2], curve A, corresponding to the voltage provided by the first power supply module 130, being above curve B, corresponding to the voltage provided by the second power supply module 140, on the section B1, corresponding to operation in nominal operating mode).

[0069] Concerning the second power supply module 140, the transformation ratio of the transformer 142 is between a minimum transformation value T2_min and a maximum transformation value T2_max.

[0070] For example, T2_min is equal to 0.1 and, more particularly 0.2, and more particularly 0.5. For example, T2_max is equal to 0.99, more particularly 0.8 and more particularly 0.7.

[0071] For example, for such a transformation ratio, in nominal operating mode, the voltage supplied Valim2T_nom by the second power supply module 140 at the output of transformer 142 includes a minimum voltage Valim2T_nom_min and a maximum voltage Valim2T_nom_max.

[0072] For example, the voltage Valim2T_nom is between OVac and 300 Vac, which corresponds to a direct voltage between 0 and 440 Vdc.

[0073] The use of a transformer 142, having a transformation ratio less than 1, in the second power supply module 140 makes it possible, in the example, to lower the maximum voltage Valim2_nom_max supplied by the second power supply module 140 to 300 Vac, which is lower than the lower voltage terminal supplied by the first power supply module 130, which is 350 Vac.

[0074] The presence of the transformer 142 having a transformation ratio less than 1 makes it possible to reduce the voltage range Valim2T_nom provided by the second voltage module.

[0075] In the present example, in nominal operating mode, following the integration of the transformers 132, 142, the maximum voltage Valim2T_nom_max supplied by the second power supply module 140 is lower than the minimum voltage ValimlT_min supplied by the first power supply module 130. This makes it possible to guarantee in nominal operating mode, after passing through the rectifier elements 108a, 108b, that the bearing controller 102 is supplied only by the first power supply module 130, connected to the electrical network.

[0076] In addition to guaranteeing a power supply in nominal operating mode via the first power supply module 130, the presence of the transformers 132, 142 makes it possible in nominal operating mode to supply a maximum voltage ValimlT_max to the bearing controller 102 less than or equal to the maximum voltage Vcp_max admitted by said controller.

[0077] In the event of a power supply failure by the first module 130, the voltage Valim2T_deg supplied by the second power supply module 140 at the output of the transformer 142 (having a transformation ratio mentioned in the example above) is between a minimum voltage value Valim2T_deg_min and a maximum voltage value Valim2T_deg_max.

[0078] For example, the minimum voltage value Valim2T_deg_min is between 70Vac and 80Vac. And the maximum voltage value Valim2T_deg_max is between 540Vac and 560Vac, which corresponds to a direct voltage between 100Vdc and 750 Vdc.

[0079] In this way, the voltage supply Valim2T_deg of the bearing controller 102 provided by the second power supply module 140 using the synchronous motor 106, operating as a generator, is included in the range of voltage values ​​Vcp admitted by the bearing controller 102 (for example between 70Vac and 560Vac).

[0080] Thus, in the presence of the transformers 132, 142, the voltage supplied by the first power supply module 130 or the second power supply module 140 is admitted by the bearing controller 102.

[0081] In a particular embodiment, the power supply system 100 comprises a device 152 for monitoring the voltage supplied by at least the first power supply module 130, preferably the first and second power supply modules 130, 140.

[0082] The monitoring device 152 is connected to the selection device 108.

[0083] The monitoring device 152 can ensure the voltage control of the first and / or of the second power supply modules 130, 140. The voltage control is done by acquiring the voltage measured by the voltage transducers 108e and 108f.

[0084] The monitoring device 152 makes it possible to alert of a failure at the level of the first power supply module, and possibly at the level of the second power supply module.

[0085] The monitoring device 152 is connected to a control-command device configured to manage the failure modes of the first power supply module 130.

[0086] The monitoring device 152 may use a PLC system to ensure voltage control of the first and / or second power supply modules 130, 140.

[0087] The monitoring device 152 can control the speed controller 105 to regulate the power that the speed controller 105 provides to the asynchronous motor.

[0088] In a particular embodiment, the power supply system comprises, downstream of the first power supply module 130 and the second power supply module 140, a capacitive filter 150 forming an energy storage means.

[0089] The capacitive filter can be formed by a capacitor, an inductance, or even a metal oxide varistor.

[0090] Advantageously, the capacitive filter allows, thanks to the energy storage provided, to allow a more flexible transition between the power supply provided by the first power supply module 130, in nominal operating mode, and the power supply provided by the second power supply module 140, in the event of failure of the first power supply module 130.

[0091] To better understand the invention, it is proposed to focus on [Fig. 2], illustrating the replacement of the voltage supply provided by the first power supply module 130 (curve A) with that provided by the second power supply module 140 (curve B, the portion B1 defining the portion of curve B in nominal operating mode, and the portion B2 defining the portion of curve B, in degraded mode, following a failure of the first power supply module 130). [Fig. 2] also illustrates a return to normal, once the failure of the first module has been resolved.

[0092] Reference I in [Fig.2], illustrates the fact that in nominal operating mode, the voltage curve A, corresponding to the first power supply module 130. Curve B1, corresponds to the curve of the voltage supplied by the second power supply module 140.

[0093] The voltage of curve A can be stabilized at a value VA-1 or oscillate between the voltage values ​​VA-2 and VA-3.

[0094] In nominal operating mode, the voltage of curve B1 can oscillate between a voltage value VB1-1 and VB1-2.

[0095] For example, VB1-1 is equal to Valim2T_nom_max.

[0096] In nominal operating mode, the voltage value of curve B1, between VB1-1 and VB1-2, is constantly lower than the minimum voltage value of curve A, between the values ​​VA-3 and VA-2.

[0097] For example, VA-2 is equal to ValimlT_max, and / or VA-3 is equal to ValimlT_min.

[0098] This corresponds to the second power supply module 140 being in the “idle” state (“ inactive”), illustrated in [Fig. 3], defining, in French terminology, a state where the second power supply module 140 derives from the voltage of the synchronous motor 106, but does not supply the bearing controller 102. This is the case, regardless of whether the voltage supply of the first power supply module 130 undergoes transient variations between the values ​​VA-2 and VA-3 or is permanent at a value VA-1. Therefore, the selection device 108 selects only the first power supply module 130 to supply voltage to the bearing controller 102.

[0099] Reference II illustrates the start of the power supply of the second power supply module 140, after the first power supply module 130 is powered by the synchronous motor for a first period of time. The voltage supplied by the second power supply module 140 changes from V0, a ​​zero voltage, to a voltage varying between VB1-1 and VB1-2.

[0100] Reference III illustrates the fact that even when the second power supply module 140 is sufficiently powered to provide power to the bearing controller 102, the voltage peaks of the curve B1, having a value VB1-1, are constantly lower than the voltage supplied by the first power supply module 130, in nominal operating mode.

[0101] Reference IV illustrates the failure of the first power supply module 130, and the sudden drop in the voltage supplied by this power supply module down to voltage V0, this results in an almost vertical drop in the voltage illustrated on curve A.

[0102] Reference V illustrates the time on the graph after curve A of the first power module 130 crosses curve B at crossover point C. After crossover point C, the voltage supplied by the second module supply voltage 140 (illustrated by curve B2, downstream of point C) is greater than the voltage supplied by the first supply module 130 (illustrated by curve A, downstream of point C). Consequently, the selection device 108 selects the second supply module 140 to supply voltage to the bearing controller 102. When the voltage supplied by the first supply module 130 is exceeded, the voltage supplied by the second module gradually decreases over time (see reference VI in [Fig.2]), until it reaches voltage V0, zero. At this time, the supply voltage supplied by the first module and the second supply module 130,140 is zero.

[0103] The voltage supplied by the second power supply module 140 reduces over time due to the reduction in speed of the synchronous motor 106, in freewheel mode, until the latter stops.

[0104] The period of time during which the bearing controller 102 is powered by the second power supply module may be between 1s and 60s, more particularly between 5s and 30s. During this period of time, the voltage supplied to the bearing controller 102 is reduced over time until it reaches a minimum voltage Vmin. This supply time period is illustrated in [Fig.4] and corresponds to the “duty” (“active”) state, defining, in French terminology, a state where the second power supply module 140 provides power to the bearing controller 102.

[0105] From this minimum voltage Vmin, the ball bearings of the bearing 104, called "landing gears", can take over and receive the motor shaft 110 of the synchronous motor 106. The motor shaft lands on the ball bearings of the bearing 104, until the final stop of the motor, without causing any damage to the bearing 104.

[0106] In one embodiment, the minimum DC voltage Vmin supplied by the second power supply module 140, before the motor shaft 110 comes to rest on the ball bearings of the bearing 10, can be between 60Vdc and 140Vdc, preferably 70Vdc and 120Vdc.

[0107] Preferably, this minimum voltage Vmin is supplied at a frequency Fmin. The frequency Fmin can be between 60 Hz and 100 Hz. This frequency corresponds to the minimum frequency at which the bearing controller 102 can be powered.

[0108] When the voltage supplied by the second power supply module 140 reaches V0 and becomes zero, a rest period follows during which the bearing controller 102 can no longer be supplied by the second power supply module 140. This supply time period is illustrated in [Fig.4] and corresponds to the “rest” state, defining, in French terminology, a rest state, where the second power supply device no longer supplies power to the bearing controller 102.

[0109] Preferably, the rest period is between 30s and 160s, more particularly between 100s and 140s, even more precisely of the order of 120s.

[0110] Reference VIII illustrates the moment when the fault of the first power supply module 130 is resolved and the first power supply module allows the bearing controller 102 to be powered again.

[0111] Advantageously, the supply system 100 according to the invention is configured to be used in a cycle gas compression system of a refrigeration and / or gas liquefaction system comprising a supply system according to one of the embodiments described. The compression system may be a land-based device or included on a maritime device such as an LNG carrier.

Claims

Claims

1. A power supply system (100) for a magnetic bearing controller (102) of a permanent magnet synchronous motor (106) comprising: - a first electrical power supply module (130), configured to be connected to an electrical network and to supply voltage to the magnetic bearing controller (102), - a second electrical power supply module (140) configured to supply voltage to the magnetic bearing controller (102), the voltage of the second power supply module (140) being derived from the synchronous motor (106), - a device (108) for selecting the first power supply module (130) or the second power supply module (140) for supplying voltage to the magnetic bearing controller (102), wherein the second power supply module (140) is configured to supply, in a nominal operating regime, a voltage lower than the voltage supplied by the first power supply module (130),the second power supply module (140) is connected in parallel with the first power supply module (130) and upstream of the magnetic bearing controller (102), the selection device (108) is configured to select the power supply module (130, 140) providing the highest voltage to the magnetic bearing controller (102).,

2. System according to claim 1, characterized in that the selection device (108) comprises a voltage rectifying element (108a, 108b).

3. System according to claim 1 or 2, characterized in that the second power supply module (140) is configured to be supplied with voltage by the motor (106): - using a speed variator (105), in nominal operating mode; and / or - by the motor acting as a generator when it is freewheeling.

4. System according to one of the preceding claims, characterized in that the selection device (108) comprises at least two OR-ing diodes (108c, 108d), the first OR-ing diode (108c) is arranged downstream of the first power supply module (130), and the second OR-ing diode (108d) is arranged downstream of the second power supply module (140), the first and second OR-ing diodes (108c, 108d) being arranged in parallel.

5. System according to one of the preceding claims, characterized in that the first power supply module (130) and / or the second power supply module (140) comprises a transformer (132, 142).

6. System according to one of the preceding claims, characterized in that the voltage admitted by the magnetic bearing controller (102) is between 70Vdc and 800Vdc, preferably between 100Vdc and 750Vdc.

7. System according to one of the preceding claims, characterized in that the second power supply module (140) is configured to supply a minimum voltage of between 70Vdc and 120Vdc, preferably 100Vdc to the magnetic bearing controller (102) at a frequency of between 60Hz and 100Hz, preferably 80Hz.

8. System according to one of the preceding claims, characterized in that it comprises a device (152) for monitoring the voltage supplied by the power supply modules.

9. System according to one of the preceding claims, characterized in that it comprises, downstream of the first power supply module (130) and the second power supply module (140), a capacitive filter (150) forming an energy storage means.

10. A cycle gas compression system of a refrigeration and / or gas liquefaction system comprising a supply system (100) according to one of the preceding claims.

11. A method for powering a magnetic bearing controller (102) of a permanent magnet synchronous motor (106) comprising: a step (SI) of selecting by a selection device (108) a power supply module (130, 140) providing the highest voltage for powering the magnetic bearing controller (102), the selection being made between: - a first electrical power supply module (130), configured to be connected to an electrical network and to supply voltage to the magnetic bearing controller (120), and - a second electrical power supply module (140), mounted in parallel with the first electrical power supply module (130), the voltage supplied by the second electrical power supply module (140) being derived from the synchronous motor (106), the second electrical power supply module (140) providing, in a nominal operating regime, an electrical voltage lower than the voltage supplied by the first power supply module (130), a power supply step (S2) in which the magnetic bearing controller (102) is supplied by the power supply module (130, 140) selected by the selection device (108).

12. A method according to claim 11, characterized in that the synchronous motor (106) acts as a generator when freewheeling.

13. Method according to claim 11 or 12, characterized in that the second power supply module (140) supplies the magnetic bearing controller (102) for a period of time between 1s and 60s, more particularly between 5s and 30s.

14. Method according to one of claims 11 to 13, characterized in that when the second power supply module (140) supplies the magnetic bearing controller (102), the voltage supplied to the magnetic bearing controller (102) reduces over time until it reaches a minimum voltage.

15. Method according to claim 14, characterized in that the minimum voltage supplied to the magnetic bearing controller (102) is between 70Vdc and 120Vdc and has a frequency between 60Hz and 100 Hz.

16. Method according to one of claims 11 to 15, characterized in that the power supply of the magnetic bearing controller (102) by the second electrical power supply module (140) is followed by a rest period during which the magnetic bearing controller (102) is not powered by the second power supply module (140).

17. Method according to claim 16, characterized in that the rest period is between 30s and 160s, more particularly between 100s and 140s, and more precisely 120s.

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