Power control processes and systems for an electrical machine

Abstract

Power control methods and systems for an electrical machine Power control system for an electrical machine, comprising a management interface (9) configured to manage power exchanged between an electrical device and an electrical machine (2), the management interface (9) comprising four switching devices (10 to 13) forming a bridge circuit (P), and a capacitive device (Ca) electrically coupled between terminals (BP1, BP2) of the bridge circuit (P);each switching device being controlled and configured to operate as a unidirectional voltage switch and a bidirectional current switch, and an electronic control unit (20) configured to control the four switching devices so as to discharge the capacitive device (Ca) and to control a closing of each of the four switching devices when a voltage between the terminals (BP1, BP2) of the bridge circuit (P) is strictly less than a voltage threshold, in order to keep the capacitive device (Ca) discharged. Figure for the abstract: Fig.2;

Description

Title of the invention: Power control methods and systems for an electrical machine technical field

[0001] The present invention relates to the power control of electrical machines, such as electric motors and generators, in particular the power management of polyphase electric machines with variable speeds, and more particularly the power management of variable speed motorization systems equipped with a polyphase electric motor. STATE OF THE ART

[0002] Currently, there are different methods for managing the power supplied or consumed by electrical machines.

[0003] One can cite, for example, the publication: “Applying MERS for Induction Motor Driving, Miao-miao Cheng, Takanori Isobe, Shuhei Kato, Kazuhiko Fukutani, Hideo Sumitani, and Ryuichi Shimada; journal of the Japan Institute of Power Electronics J1PE-37-12 Vol. 37 (2012.3), pages 139 to 145”, which discloses a use of a MERS type device (corresponding to the acronym for “Magnetic Energy Recovery Switch” in English) to manage the operation of an electric motor.

[0004] Further reference can be made to the publication: “Control and Design Principle of SVC-MERS—a New Reactive Power Compensator with Line Frequency Switching and Small Capacitor, Daisuke Shiojima, Miao-miao Cheng, Takanori Isobe, and Ryuichi Shimada; Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology; Tokyo, Japan 152-8550; in IEEE (2012) 978-1-4673-0803-8 / 12,” ​​which also discloses the use of a MERS-type device to manage the operation of an electrical generator. This publication describes a method for obtaining sinusoidal currents of different shapes to achieve different variations in the reactive power output of the generator.

[0005] We can also cite the publication: “Feasible Series Compensation Applications using Magnetic Energy Recovery Switch (MERS), Jan A. Wiik, Takanori Isobe, Taku Takaku, F. Danang Wijaya, Kazuhiro Usuki, Nobuyuki Arai and Ryuichi Shimada; Tokyo Institute of Technology NI-33, 2-12-1 O-okayama, Meguro-ku, Tokyo, Japan; Fuji Electric Device Technology Co., Ltd, 4-18-1, Tsukama, Matsumoto, Japan,” which discloses a use of MERS-type devices as series compensators in systems high power transmission where the power flow can be controlled and increased.

[0006] But the methods proposed in these publications are not sufficiently robust and do not provide sufficient safety, particularly when controlling an electrical machine to increase or decrease the power exchanged with an electrical energy source or an electrical device. SUMMARY

[0007] An object of the present invention is therefore to overcome the disadvantages mentioned above, and more particularly to provide simple and robust means for managing the electrical power supplied or consumed by an electrical machine.

[0008] Another objective is to provide means to ensure safety, in particular electrical safety, during power change commands intended for electrical machines.

[0009] According to one aspect of the invention, a power control method for an electrical machine is proposed, comprising: - the provision of a management interface, the management interface comprising a first terminal configured to be electrically coupled to an electrical device taken from an electrical power source or an electrical appliance, and a second terminal configured to be electrically coupled to an electrical machine, the management interface being configured to manage power exchanged between the electrical device and the electrical machine, the management interface comprising four switching devices forming a bridge circuit, the bridge circuit having first and second terminals coupled respectively to the first and second terminals of the management interface, the management interface also comprising a capacitive device electrically coupled between the third and fourth terminals of the bridge circuit; each switching device being controlled and configured to operate as a unidirectional voltage switch and a bidirectional current switch, and - a first control step configured to control the four switching devices so as to discharge the capacitive device.

[0010] The method includes a second control step configured to control the closing of each of the four switching devices when a voltage between the third and fourth terminals of the bridge circuit is strictly less than a voltage threshold, in order to keep the capacitive device discharged.

[0011] Thus, such a method makes it possible to ensure that the capacitive device is kept discharged for safety reasons, in particular to prevent overheating of the electrical machine, or to prevent exceeding the limits of operation tolerated by the electrical machine. Furthermore, during the second control stage, the switching devices in the bridge circuit are not periodically switched, which prevents excessive system power consumption and limits Joule heating losses in the control interface. Another advantage is that during the second control stage, the switching devices are simply controlled by a single closing command. Thus, it is not necessary to periodically alternate the switching devices, which would involve complex control of the switching devices. Advantageously, precision is not required during the second control stage.The method according to the invention makes it possible to keep the capacitive device discharged without the risk of an unexpected restart, for example due to incorrect switching of the switching devices which could cause the capacitive device to recharge. Thus, the bypass of the capacitive device of the control interface is guaranteed in the event of a malfunction of the switching devices of the control interface or an incorrect control of these devices, while keeping the electrical machine running.

[0012] According to another aspect of the invention, a power control method for an electrical machine is proposed, comprising: - the provision of a management interface, the management interface comprising a first terminal configured to be electrically coupled to an electrical device taken from an electrical power source or an electrical appliance, and a second terminal configured to be electrically coupled to an electrical machine, the management interface being configured to manage power exchanged between the electrical device and the electrical machine, the management interface comprising four switching devices forming a bridge circuit, the bridge circuit having first and second terminals coupled respectively to the first and second terminals of the management interface, the management interface also comprising a capacitive device electrically coupled between the third and fourth terminals of the bridge circuit; each switching device being controlled and configured to operate as a unidirectional voltage and bidirectional current switch, and - a first control step configured to control the four switching devices in order to discharge the capacitive device.

[0013] The control interface includes an additional electrically coupled switch device between the third and fourth terminals of the bridge circuit, and the method includes a second control step configured to control the closing of the additional switch device when a voltage between the The third and fourth terminals of the bridge circuit are strictly below a voltage threshold, in order to keep the capacitive device discharged.

[0014] According to another aspect, a power control system for an electrical machine is proposed, comprising: - a management interface comprising a first terminal configured to be electrically coupled to an electrical device taken from an electrical power source or an electrical appliance, and a second terminal configured to be electrically coupled to an electrical machine, the management interface being configured to manage power exchanged between the electrical device and the electrical machine, the management interface comprising four switching devices forming a bridge circuit, the bridge circuit having first and second terminals coupled respectively to the first and second terminals of the management interface, the management interface also comprising a capacitive device electrically coupled between the third and fourth terminals of the bridge circuit, each switching device being controlled and configured to operate as a unidirectional voltage switch and a bidirectional current switch, and - an electronic control unit configured to control the four switching devices in order to discharge the capacitive device.

[0015] The electronic control unit is configured to command a closure of each of the four switching devices when a voltage between the third and fourth terminals of the bridge circuit is strictly less than a voltage threshold, in order to keep the capacitive device discharged.

[0016] According to another aspect, a power control system for an electrical machine is proposed, comprising: - a management interface comprising a first terminal configured to be electrically coupled to an electrical device taken from an electrical power source or an electrical appliance, and a second terminal configured to be electrically coupled to an electrical machine, the management interface being configured to manage power exchanged between the electrical device and the electrical machine, the management interface comprising four switching devices forming a bridge circuit, the bridge circuit having first and second terminals coupled respectively to the first and second terminals of the management interface, the management interface also comprising a capacitive device electrically coupled between the third and fourth terminals of the bridge circuit, each switching device being controlled and configured to operate as a unidirectional voltage switch and a bidirectional current switch, and - an electronic control unit configured to control the four switching devices in order to discharge the capacitive device.

[0017] The management interface includes an additional electrically coupled switch device between the third and fourth terminals of the bridge circuit, the electronic control unit being configured to command a closure of the additional switch device when a voltage between the third and fourth terminals of the bridge circuit is strictly less than a voltage threshold, in order to keep the capacitive device discharged. BRIEF DESCRIPTION OF THE FIGURES

[0018] The other objects, features and advantages of the present invention will become apparent from an examination of the following description and the accompanying drawings in which:

[0019] [Fig.1] [Fig.1] represents an embodiment of a power control system for an electrical machine;

[0020] [Fig.2] [Fig.2] represents another embodiment of a control system power for an electrical machine;

[0021] [Fig.3] ;

[0022] [Fig.4] ;

[0023] [Fig. 5] Figures 3 to 5 represent the main steps of a method of putting into implementation of a power control method for an electrical machine; and

[0024] [Fig.6] ;

[0025] [Fig. 7] Figures 6 and 7 represent other embodiments of a system of power control for an electrical machine.

[0026] The drawings are given by way of example and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate understanding of the invention and are not necessarily to scale with practical applications. DETAILED DESCRIPTION

[0027] Before beginning a detailed review of embodiments and implementations of the invention, optional features which may possibly be used in association or alternatively are stated below.

[0028] According to one example, the management interface includes an additional electrically coupled switch device between the first and second terminals of the management interface, and in that the second control stage is further configured to command a closure of the additional switch device when the voltage between the third and fourth terminals of the bridge circuit is strictly less than the voltage threshold.

[0029] According to one example, the method includes, after the second control step, a third control step configured to control the opening of the additional switching device, and then to control the four switching devices of the bridge circuit so as to manage the power exchanged between the electrical device and the electrical machine.

[0030] According to one example, the method includes, after the second control step, a third control step configured to control the four switching devices in order to manage the power exchanged between the electrical device and the electrical machine.

[0031] According to one example, the method includes a measurement of the voltage between the third and fourth terminals of the bridge circuit, and when the voltage is greater than or equal to a voltage threshold, the first control step is carried out, then the second control step.

[0032] According to another example, the method includes a measurement of at least one temperature, said at least one temperature being taken from a temperature of the electrical machine and a temperature of the control interface, and when said at least one temperature is greater than or equal to a temperature threshold, the first control step is carried out, and then the second control step.

[0033] According to another example, an electromechanical conversion chain is proposed, comprising an electrical machine, an electrical device taken from an electrical energy source or an electrical appliance, and a power control system as defined above.

[0034] It is specified that within the framework of the present invention, the expressions "A coupled to B", "A electrically coupled to B", "A connected to B" or "A electrically connected to B" are synonymous with "A is in electrical connection with B" and do not necessarily mean that there is no component between A and B. Thus these expressions refer to an electrical connection between two elements, this connection being either direct or indirect; this means that it is possible that between a first device A and a second device B which are electrically connected, linked or coupled, a current flows in A, in B, and along the path connecting A to B, this path being either or not including other electrical equipment.

[0035] Conversely, in the context of the present invention, the term "electrically connected directly" or "directly connected" refers to a direct electrical connection between two elements. This means that between a first device A and a second device B that are electrically connected directly, no other equipment is present, other than an electrical connection or several electrical connections.

[0036] It is specified that in the context of the present invention, the term "electrically placed" or "electrically located" means a positioning of a device on a line in which a current flows.

[0037] It is specified that within the framework of the present invention, the term "A electrically coupled between B and C" means a positioning of a device A on a line connecting B to C in which a current flows between A, B and C. The device A can be electrically coupled to B and C, either in series or in parallel.

[0038] Figures 1, 2, 6 and 7 show different embodiments of a power control system 1 for an electrical machine 2. Figures 3 to 7 show the main steps of different implementation methods of a power control process for an electrical machine 2.

[0039] Furthermore, in figures 1 and 2, an electromechanical conversion chain 100 comprising an electrical machine 2, an electrical device 3, and the power control system 1 is shown.

[0040] Generally, the electric machine 2 is configured to convert electrical energy into mechanical energy (when the electric machine operates in motor mode) or mechanical energy into electrical energy (when the electric machine operates in generator mode). The electric machine 2 comprises a stator having several coils and a rotor with separate or unseparated excitation and or unseated control, for example a permanent magnet or wound-rotor synchronous machine, a squirrel-cage or wound-rotor induction machine, or a synchronous-reluctance or variable-reluctance machine.

[0041] When the electric machine 2 operates in motor mode, it consumes current and voltage to provide mechanical torque. When the electric machine 2 operates in generator mode, it supplies electrical current and voltage to the electrical device 3. Preferably, the electric machine 2 is polyphase, meaning that it comprises N phases (where N is an integer). For example, as illustrated in [Fig. 2], N is equal to 3. In this case, the electric machine 2 is three-phase, meaning that it comprises three phases A, B, and C.

[0042] Furthermore, the electrical device 3 can be an electrical energy source 4 (and the electrical device 3 can supply energy to the machine 2 in motor mode, or optionally receive energy from the machine 2 in generator mode) or an electrical appliance 400 (i.e., an electrical energy-consuming appliance). The source 4 can be a current source or a voltage source. The source can also be an electrical power distribution network to supply alternating voltage and current. For example, the source 4 is a battery, to store and / or to provide electrical energy, in particular from a direct current (Vdc) voltage.

[0043] Preferably, the electromechanical conversion chain 100 comprises a power converter 5 electrically coupled to the electrical device 3. The power converter 5 with the electrical device 3 form an assembly 30, also noted as electrical system 30.

[0044] Generally, the power converter 5 is configured to exchange alternating voltage and current with the electrical machine 2. If the electrical device 3 is an electrical energy source 4, the power converter 5 can be configured to convert a direct current voltage and current supplied by the source 4 into an alternating voltage and current for the electrical machine 2 (in motor mode). For example, the power converter 5 is variable frequency. For example, the power converter 5 can be an inverter or a variable frequency drive. If the electrical device 3 is an electrical appliance 400, the power converter 5 is configured to convert an alternating voltage and current supplied by the electrical machine 2 (in generator mode) into a direct or alternating voltage and current for the electrical appliance 400.For example, the power converter 5 can be a diode rectifier or a controlled rectifier. Generally, the power converter 5 is electrically coupled to the electrical device 3 by an electrical connection having M phases (where M is an integer). M can be equal to 2, in the case of direct current, or equal to 3 for alternating current.

[0045] For example, as illustrated in [Fig. 2], the electrical device 3 is a direct current (DC) power source 4. The converter 5 comprises, for each phase A, B, C, of ​​the electrical machine 2, a group of two switches 6, 7 electrically connected in series. For each phase A, B, C, the two switches 6, 7 in the group are connected in parallel with the source 4. Each group of two switches 6, 7 supplies an alternating voltage and current to an output terminal of the converter G1 to G3 associated with the group. The output terminal G1 to G3 of the converter 5 associated with a group is connected between the two switches in the group. Furthermore, the converter 5 comprises, for each of the switches 6, 7 in each group, a diode 8 connected in parallel across the terminals of the switch 6, 7.

[0046] More specifically, the power control system 1 includes a management interface 9 and an electronic control unit 20.

[0047] Generally, the control interface 9 is configured to manage power exchanged between the electrical device 3 and the electrical machine 2. The control interface 9 is electrically coupled between the electrical device 3 and the electrical machine 2. Preferably, the control interface 9 is coupled between the converter power converter 5 and electric machine 2, as illustrated in Figures 1 and 2. Preferably, the management interface 9 is electrically coupled in series between the power converter 5 and the electric machine 2, as illustrated in [Fig.2].

[0048] The management interface 9 includes at least one first terminal BEI to BE3 configured to be electrically coupled to the electrical device 3, and at least one second terminal BS1 to BS3 configured to be electrically coupled to the electrical machine 2. More specifically, the management interface 9 includes, for each phase A, B, C, of ​​the electrical machine 2, a second terminal BS1 to BS3 coupled to phase A, B, C. In addition, the management interface 9 includes, for each group of switches of the power converter 5, a first terminal BEI to BE3 coupled to an output terminal G1 to G3 of the converter 5.

[0049] Furthermore, for each phase A, B, C of machine 2, interface 9 comprises a group GA, GB, GC of switching devices 10 to 13. Each group GA, GB, GC of switching devices 10 to 13 is associated with a phase A, B, C of machine 2. In addition, each group GA, GB, GC of interface 9 comprises four switching devices 10 to 13 forming a P-bridge circuit. The four switching devices 10 to 13 in each group GA, GB, GC are also said to be bridge-connected. In the example illustrated in [Fig. 2], the control interface comprises three P-bridge circuits. Each P-bridge circuit has a first terminal e1 to e3 and a second terminal s1 to s3. The first terminal el to e3 of a P-bridge circuit is coupled, preferably directly, to a first terminal BEI to BE3 of the management interface 9. The second terminal si to s3 of a P-bridge circuit is coupled, preferably directly, to a second terminal BS1 to BS3 of the management interface 9.

[0050] In addition, the management interface 9 also includes, for each P-bridge circuit, an associated electrically coupled capacitive device Ca, preferably directly, between the third and fourth terminals BPI, BP2 of the P-bridge circuit. A capacitive device Ca is also said to be associated with a group GA, GB, GC of switching devices 10 to 13. For example, a capacitive device Ca can be a capacitor, a capacitor, an accumulator, a supercapacitor, or a set of several of these aforementioned elements.

[0051] Generally, each switch device 10 to 13 is controlled and configured to operate as a unidirectional voltage switch and a bidirectional current switch. For example, a controlled switch 10 to 13 can be an IGBT (or "Insulated Gate Bipolar Transistor") or a MOSFET (or "Metal Oxide Semiconductor Field Effect Transistor").

[0052] In addition, the electronic control unit 20 is configured to control the closing and opening of the four switch devices 10 to 13 of each of the groups GA, GB, GC of the management interface 9. Preferably, each switch device 10 to 13 includes a control terminal coupled to the electronic control unit 20, via connections Cl, so that the electronic control unit 20 can control the closed and open state (i.e. respectively passing and blocking) of the switch devices 10 to 13.

[0053] Advantageously, each group GA, GB, GC of the control interface 9 includes a diode 14 connected in parallel with the input and output terminals of each switch device 10 to 13 in the group GA, GB, GC. Such a diode 14 ensures the bidirectionality of the alternating current flowing within each assembly, referred to as the diode / switch assembly, formed by a switch device 10 to 13 and an associated diode 14 connected in parallel with the switch device 10 to 13. A diode 14 ensures the spontaneous closure of the diode / switch assembly when the current becomes zero. Thus, the two diodes 14 of a first leg comprising the switch devices 10, 11 coupled to the first terminal 11 of the P-bridge circuit, become conducting when the voltage across them becomes zero (i.e., across the third and fourth terminals BP1, BP2 of the P-bridge circuit) in order to ensure current continuity.Thus, when a switching device 10 to 13 is in a blocking state, meaning that no current flows through the switching device 10 to 13, the associated diode 14 conducts in only one direction, or positive or negative sign, of the current. Conversely, when a switching device 10 to 13 is in a conducting state, it allows current to flow through the switching device 10 to 13 in the opposite direction, or sign of the current. Diode 14 ensures current flow in at least one direction, particularly when its associated switching device malfunctions. In other words, diodes 14 prevent the capacitive devices Ca from recharging (after being discharged) before the next current half-cycle, that is, when the alternating current changes direction.

[0054] Generally, the power exchanged between the electrical device 3 and the electrical machine 2 has a real component, called active power, and an imaginary component, called reactive power. Thus, the control interface 9 is adapted to supply a portion of the reactive power to the electrical machine 2, whether the electrical machine is in motor mode or generator mode. More specifically, the portion of reactive power supplied to the electrical machine 2 is a function of the amount of energy stored in the capacitive devices Ca of the control interface 9. In other words, the portion of reactive power supplied by the control interface 9 is a function of the state of charge of the capacitive devices Ca of the control interface 9.

[0055] Generally, when the electrical machine 2 is in working order, an alternating current I flows between the electrical device 3 and the electrical machine 2, via the control interface 9.

[0056] Furthermore, the power control system 1 is said to be in normal operating mode when the control interface 9 is functioning, that is, when the capacitive devices Ca charge and discharge during power exchanges between the electrical device 3 and the electrical machine 2. For example, the control interface 9 can supply reactive power to the machine 2 to increase the magnetic flux of the machine 2, thereby increasing the performance of the electrical machine 2. In particular, when the magnetic flux of the electrical machine 2 increases, the torque increases. In cases where this increase is not controlled, the magnetic flux may exceed the recommended operating conditions and may lead to overheating.It is therefore advantageous to be able to activate or deactivate the reactive power supply via the management interface 9, for example, in the event of a fault or generally to manage the power of machine 2. Activation and deactivation can be performed without interrupting the operation of electrical machine 2. For the sake of simplicity, we will subsequently refer to activating the reactive power supply via the management interface 9 as activating interface 9, and deactivating the reactive power supply via the management interface 9 as deactivating interface 9. With or without an increase in the reactive power supplied to machine 2, the power control system 1 is in normal operating mode and machine 2 is functioning.

[0057] Generally, disabling interface 9 includes first and second command steps Cdl, Cd2.

[0058] The first control step Cdl is configured to control, via the electronic control unit 20, for at least one P-bridge circuit, and preferably for each P-bridge circuit, the four switching devices 10 to 13 of the P-bridge circuit so as to discharge the capacitive device Ca associated with the P-bridge circuit. For example, the first control step may include a first closing of the first two switching devices 10, 13 arranged along a first diagonal of the P-bridge circuit, alternating with a second closing of the other two switching devices 11, 12 arranged along the second diagonal of the P-bridge circuit. Furthermore, the first closing is carried out simultaneously with a first opening of the switching devices 11, 12 of the second diagonal. The simultaneity of the first closing and the first opening is illustrated in [Fig.3] and this simultaneity is noted as the first command. The second closing is carried out simultaneously with a second opening. Switch devices 10, 13 of the first diagonal. The simultaneity of the second closing and the second opening is noted as the second command.

[0059] It should be noted that to discharge the capacitive device Ca associated with the P-bridge circuit, the first command is executed when, for example, the current flows in one direction, for example when the current I is negative, and the second command is executed when the current I is positive (i.e., the current flows in a second direction opposite to the first), that is, when the current I changes sign. Figures 3, 4, 6, and 7 show the positive current I flowing in the second direction.

[0060] Conversely, to charge the capacitive device Ca associated with the P-bridge circuit, the first command is executed when the current I is positive, and the second command is executed when the current I is negative, that is to say when the current I changes sign.

[0061] In other words, the first control stage Cdl comprises an alternating control of the diagonals of the P-bridge circuit. In particular, the alternation between the first and second diagonal controls is performed when the alternating current I changes sign, that is, when the current I passes through zero. Furthermore, the alternation is performed periodically according to the frequency of the alternating current.

[0062] The second control step Cd2 is configured to control, via the electronic control unit 20, the closing of each of the four switching devices 10 to 13 of at least one P-bridge circuit, as illustrated in [Fig. 4]. Furthermore, this closing occurs when a voltage Vc between the third and fourth terminals BPI, BP2 of the P-bridge circuit is strictly less than a voltage threshold Veps, in order to keep the capacitive device Ca discharged. Preferably, for each P-bridge circuit, the closing of each of the four switching devices 10 to 13 of the P-bridge circuit is controlled when the voltage Vc between the third and fourth terminals BPI, BP2 of the P-bridge circuit is strictly less than a voltage threshold Veps, in order to keep the capacitive device Ca associated with the P-bridge circuit discharged.Closing a switch device 10 to 13 of the management interface 9 results in forced (i.e., sustained) conduction of the switch device 10 to 13. The second control step Cd2 allows the switch devices 10 to 13 to be controlled differently from the first control step Cdl. In other words, when the voltage Vc is strictly less than a voltage threshold Veps, the first control step Cdl is stopped, and then the second control step Cd2 is executed.

[0063] Thus, it is guaranteed that the capacitive Ca devices each have a minimum stored energy, or even zero energy. Furthermore, this implementation method allows for Minimize Joule effect losses in the conversion chain 100. Indeed, when the switching devices 10 to 13 of a P-bridge circuit are all closed, each switching device 10 to 13 carries a current equal to 1 / 2, where I corresponds to the current present at the first and second terminals el, si of the P-bridge circuit. We then obtain the following relationships:

[0064] Req = 2 x (Rint / 2) = Rint, with: - Req: the equivalent resistance of the P-bridge circuit (expressed in Ohms); and - Rint: the resistance of a 10 to 13 switching device (expressed in Ohms).

[0065] In other words, the Joule losses of the control interface 9 correspond to the Joule losses of a switching device 10 to 13 of a P-bridge circuit.

[0066] Figure 5 shows the main steps of an implementation method for a power control system for an electrical machine 2. The method can be implemented using the power control system 1 as defined above. The method can include an initial control step CdO in which the switching devices 10 to 13 of the control interface 9 are controlled so that the machine 2 is in its normal operating state. Then, when it is desired to deactivate the interface 9, the first control step Cdl is performed to discharge the capacitive device(s) Ca. Then, the second control step Cd2 is performed to ensure that the capacitive devices Ca are kept discharged.Preferably, we stop the first step of the Cdl command, then we execute the second step of the Cd2 command.

[0067] Advantageously, the method includes measuring the voltage Vc between the third and fourth terminals BPI, BP2 of the P-bridge circuit, and when the voltage is greater than or equal to a voltage threshold, the first control step Cdl is executed, followed by the second control step Cd2. This prevents exceeding the maximum operating voltage supported by the electrical machine 2.

[0068] The method may further include measuring at least one temperature, said at least one temperature being taken from the temperature of the electrical machine 2 and a temperature of the control interface 9. When the measured temperature is greater than or equal to a temperature threshold, the first control step Cd1 is executed, followed by the second control step Cd2. This prevents the control system 1 from heating up.

[0069] Furthermore, the method may include a third control step Cd3, called the reconnection step. The activation of interface 9 is also said to include the third control step Cd3. During this reconnection step Cd3, the deactivation of interface 9 is stopped by controlling the switching devices 10 to 13 of the bridge circuits P so as to return to the normal operating state, that is, to the initial control step CdO.

[0070] For example, after the second control step Cd2, a third control step Cd3 is carried out, configured so as to control, for each group of switching devices GA, GB, GC, the four switching devices 10 to 13 in order to manage the power exchanged between the electrical device 3 and the electrical machine 2. For example, during the third control step Cd3, it is possible to control, for each group of switching devices GA, GB, GC, the four switching devices 10 to 13 in order to load the capacitive devices Ca associated respectively with the groups GA, GB, GC.

[0071] In particular, when interface 9 is to be reactivated, the reconnection step is performed when the alternating current I passes through zero. In the case where the electrical machine 2 has three phases A, B, C, the three phases are reconnected successively, as the current flowing in a phase A, B, C passes through zero.

[0072] The reconnection step Cd3 can be performed in different ways. According to one possibility, it is possible to restart from the second control step Cd2 by performing a reverse process. The reverse process consists of repeating the first control step Cdl, which imposes the command enabling the discharge of the capacitive devices Ca, and then returning to the initial control step CdO. This allows the system to be restarted gradually and avoids excessively abrupt changes in the behavior of the electric machine 2. According to a second possibility, it is possible to return directly to the initial control step CdO after stopping the second control step Cd2.

[0073] According to another embodiment, illustrated in [Fig. 6], the control interface 9 comprises at least one additional switch device intBP, denoted internal switch, for example, a set of internal additional switches. Preferably, the control interface 9 comprises, for each P-bridge circuit, an additional switch device intBP, electrically coupled between the third and fourth terminals BPI, BP2 of the P-bridge circuit. In this case, when the first control step Cdl is performed, the internal switch intBP is controlled by the electronic control unit 20 to be in the open state.The second control step Cd2 is configured to command, via the electronic control unit 20, the closure of the additional switch device intBP when the voltage Vc between the third and fourth terminals BPI, BP2 of the P-bridge circuit is strictly below the voltage threshold Veps, in order to keep the capacitive device Ca discharged. According to one implementation, the first control step Cdl is maintained when the second control step Cd2 is executed. In other words, the alternating control of the diagonals of the P-bridge circuits is maintained in discharge mode to prevent any unintended recharging of the capacitors. associated capacitive devices Ca. Thus, reactivating interface 9 to return to normal operating mode can be facilitated simply by re-engaging the internal switches intBP and then stopping the first control step Cdl. It should be noted that this embodiment generates more Joule losses in the control interface 9, since the equivalent resistance Req is equal to 2 x Rint + RintBP, where RintBP corresponds to the resistance of the additional switch device (expressed in Ohms).

[0074] Figure 7 shows another embodiment in which the interface Management interface 9 includes at least one additional switch device extBP, referred to as an external switch, for example, a set of additional external switches, electrically coupled between the first and second terminals BEI, BS1 of the management interface 9. In this case, when the first control step Cdl is executed, the external switch intBP is controlled by the electronic control unit 20 to be in the open state. Furthermore, the second control step Cd2 is configured to command the external switch extBP to close when the voltage Vc between the third and fourth terminals BPI, BP2 of the P-bridge circuit is strictly less than the voltage threshold Veps.

[0075] In embodiments where system 1 includes an external switch extBP or at least one internal switch intBP, the third control step Cd3 is configured to control the opening of each additional switch device intBP, extBP to return to the initial control step CdO. Generally, the third control step Cd3 is configured to control the four switch devices 10 to 13 so as to manage the power exchanged between the electrical device 3 and the electrical machine 2. For example, the third control step Cd3 is configured to control the four switch devices 10 to 13 of each P-bridge circuit so as to load each associated capacitive device Ca.

[0076] The electronic control unit 20 is further configured to control the closing and opening of the internal switches intBP and the external switch extBP.

[0077] The internal switches intBP and the external switch extBP can be controlled switches of the IGBT or MOSFET type.

[0078] Thus, thanks to the process just described, it is possible to manage the phases of use of the management interface 9 and minimize energy consumption during the phases of deactivation of the interface 9. It is therefore possible not to penalize the efficiency of the conversion chain when the deactivation of the interface 9.

[0079] Advantageously, interface 9 can be disabled for the following various reasons: - stop the increase in torque and return to an initial operating mode; - limit thermal heating of the electrical machine 2 caused by the increase in the magnetic flux of the electrical machine 2; - when a voltage or current threshold is crossed at the first BEI terminal of the management interface 9, to avoid damaging the electrical machine.

[0080] Such reconnection management makes it possible to minimize any sudden variations in voltage or current when reconnecting the management interface 9.

[0081] A method with improved reliability is provided. Redundancy of the bypass system is also provided to improve safety. Reactive power management can thus be easily activated or deactivated as needed.

Claims

Demands

1. A method for controlling power for an electrical machine, comprising: • a supply of a control interface (9), the control interface (9) comprising a first terminal (BEI) configured to be electrically coupled to an electrical device (3) taken from an electrical power source (4) or an electrical appliance (400), and a second terminal (BS1) configured to be electrically coupled to an electrical machine (2), the control interface (9) being configured to manage power exchanged between the electrical device (3) and the electrical machine (2), the control interface (9) comprising four switching devices (10 to 13) forming a bridge circuit (P), the bridge circuit (P) having first and second terminals (11, 11) coupled respectively to the first and second terminals (BEI, BS1) of the control interface (9),the control interface (9) also comprising a capacitive device (Ca) electrically coupled between the third and fourth terminals (BPI, BP2) of the bridge circuit (P); each switching device (10 to 13) being controlled and configured to operate as a unidirectional voltage switch and a bidirectional current switch, and • a first control step (Cdl) configured to control the four switching devices (10 to 13) so as to discharge the capacitive device (Ca), characterized in that the method comprises a second control step (Cd2) configured to control the closing of each of the four switching devices (10 to 13) when a voltage (Vc) between the third and fourth terminals (BPI, BP2) of the bridge circuit (P) is strictly less than a voltage threshold (Veps), in order to keep the capacitive device (Ca) discharged.

2. A method for controlling power for an electrical machine, comprising: • the provision of a control interface (9), the control interface (9) comprising a first terminal (BEI)

3. configured to be electrically coupled to an electrical device (3) taken from an electrical power source (4) or an electrical appliance (400), and a second terminal (BS1) configured to be electrically coupled to an electrical machine (2), the management interface (9) being configured to manage power exchanged between the electrical device (3) and the electrical machine (2), the management interface (9) comprising four switching devices (10 to 13) forming a bridge circuit (P), the bridge circuit (P) having first and second terminals (11, 11) coupled respectively to the first and second terminals (BEI, BS1) of the management interface (9), the management interface (9) also comprising a capacitive device (Ca) electrically coupled between third and fourth terminals (BPI, BP2) of the bridge circuit (P);each switching device (10 to 13) being controlled and configured to operate as a unidirectional voltage and bidirectional current switch, and; • a first control stage (Cdl) configured to control the four switching devices (10 to 13) in order to discharge the capacitive device (Ca), characterized in that the management interface (9) includes an additional switching device (intBP) electrically coupled between the third and fourth terminals (BPI, BP2) of the bridge circuit (P), and in that the method includes a second control step (Cd2) configured to command a closure of the additional switching device (intBP) when a voltage (Vc) between the third and fourth terminals (BPI, BP2) of the bridge circuit (P) is strictly less than a voltage threshold (Veps), in order to keep the capacitive device (Ca) discharged. A method according to claim 1, wherein the management interface (9) comprises an additional switching device (extBP) electrically coupled between the first and second terminals (BEI, BS1) of the management interface (9), and wherein the second control step (Cd2) is further configured to command a closure of the additional switching device (extBP) when the voltage (Vc) between the third and fourth terminals (BPI, BP2) of the bridge circuit (P) is strictly less than the voltage threshold (Veps).

4. A method according to any one of claims 2 to 3, comprising, after the second control step (Cd2), a third control step (Cd3) configured to control the opening of the additional switching device (intBP, extBP), and then to control the four switching devices (10 to 13) of the bridge circuit (P) so as to manage the power exchanged between the electrical device (3) and the electrical machine (2).

5. Method according to claim 1, comprising, after the second control step (Cd2), a third control step (Cd3) configured to control the four switching devices (10 to 13) in such a way as to manage the power exchanged between the electrical device (3) and the electrical machine (2).

6. A method according to any one of claims 1 to 5, comprising a measurement of the voltage (Vc) between the third and fourth terminals (BPI, BP2) of the bridge circuit (P), and when the voltage (Vc) is greater than or equal to a voltage threshold, the first control step (Cdl) is carried out, followed by the second control step (Cd2).

7. A method according to any one of claims 1 to 6, comprising a measurement of at least one temperature, said at least one temperature being taken from a temperature of the electrical machine (2) and a temperature of the control interface (9), and when said at least one temperature is greater than or equal to a temperature threshold, the first control step (Cdl) is carried out, followed by the second control step (Cd2).

8. A power control system for an electrical machine, comprising: • a management interface (9) including a first terminal (BEI) configured to be electrically coupled to an electrical device (3) taken from an electrical power source (4) or an electrical appliance (400), and a second terminal (BS1) configured to be electrically coupled to an electrical machine (2), the management interface (9) being configured to manage power exchanged between the electrical device (3) and the machine

9. electrical (2), the management interface (9) comprising four switching devices (10 to 13) forming a bridge circuit (P), the bridge circuit (P) having first and second terminals (11, 12) coupled respectively to the first and second terminals (B1, BS1) of the management interface (9), the management interface (9) also comprising a capacitive device (Ca) electrically coupled between third and fourth terminals (B1, BP2) of the bridge circuit (P), each switching device (10 to 13) being controlled and configured to operate as a unidirectional voltage and bidirectional current switch, and • an electronic control unit (20) configured to control the four switching devices (10 to 13) so as to discharge the capacitive device (Ca), characterized in that the electronic control unit (20) is configured to command a closure of each of the four switching devices (10 to 13) when a voltage (Vc) between the third and fourth terminals (BPI, BP2) of the bridge circuit (P) is strictly less than a voltage threshold (Veps), in order to keep the capacitive device (Ca) discharged. Power control system for an electrical machine, comprising: • a management interface (9) comprising a first terminal (BEI) configured to be electrically coupled to an electrical device (3) taken from an electrical power source (4) or an electrical appliance (400), and a second terminal (BS1) configured to be electrically coupled to an electrical machine (2), the management interface (9) being configured to manage power exchanged between the electrical device (3) and the electrical machine (2), the management interface (9) comprising four switching devices (10 to 13) forming a bridge circuit (P), the bridge circuit (P) having first and second terminals (11, 12) coupled respectively to the first and second terminals (BEI, BS1) of the management interface (9), the management interface (9) also comprising a capacitive device (Ca) electrically coupled between third and fourth terminals (BPI, BP2) of the bridge circuit (P); each switching device (10 to 13) being controlled and configured to operate as a unidirectional voltage and bidirectional current switch, and • an electronic control unit (20) configured to control the four switching devices (10 to 13) so as to discharge the capacitive device (Ca), characterized in that the management interface (9) includes an additional switching device (intBP) electrically coupled between the third and fourth terminals (BPI, BP2) of the bridge circuit (P), the electronic control unit (20) being configured to command a closure of the additional switching device (intBP) when a voltage (Vc) between the third and fourth terminals (BPI, BP2) of the bridge circuit (P) is strictly less than a voltage threshold (Veps), in order to keep the capacitive device (Ca) discharged.

10. Electromechanical conversion chain, comprising an electrical machine (2), an electrical device (3) taken from an electrical power source (4) or an electrical apparatus (400), and a power control system according to any one of claims 8 to 9.

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