FR3129044A1 - METHOD FOR CONTROLLING A ROTATING ELECTRIC MACHINE IN A PASSIVE STATE - Google Patents

Abstract

The present invention relates to a method for controlling a rotating electrical machine (12) integrated in a hybrid traction chain (10) of a motor vehicle, said method comprising, when the rotating electrical machine (12) is in a passive state: - a step of controlling the rotating electric machine (12) in an open circuit mode in which the electronic switches of the inverter are open, - a step of controlling the electric machine (12) in a short-circuit mode in which the electronic switches of the inverter (20) are in the closed state, and - a step for controlling the electric machine (12) in an intermediate energy optimization mode in which an overall energy consumption of the traction chain ( 10) is reduced compared to short-circuit mode. Figure 1

Description

METHOD FOR CONTROLLING A ROTATING ELECTRIC MACHINE IN A PASSIVE STATE

The present invention relates to a method for controlling a rotating electrical machine in the passive state. The invention finds a particularly advantageous application for motor vehicles equipped with a hybrid traction chain.

In a manner known per se, a motor vehicle hybrid traction chain is formed by a heat engine associated with a rotating electrical machine electrically connected to a battery of an electrical network. The electric machine can either be installed on the front axle or the rear axle. The electric machine can be mechanically linked to the heat engine by means of a belt, or integrated into a gearbox, into a clutch or into any other component of the traction chain.

Conventionally, the rotating electrical machine comprises a rotor and a stator having a plurality of phases electrically connected to an inverter. For this purpose, the inverter comprises a plurality of switching arms electrically connected in parallel. Each arm includes a high side switch and a low side switch connected to each other at a midpoint, each midpoint being intended to be connected to at least one phase of a rotating electrical machine.

A control module controls the opening or closing of each switch to control the power supply to the electrical machine. Low side switches or high side switches are electronic power switches, for example of the metal-oxide field effect transistor type, also known by the acronym MOSFET (Metal Oxide Semiconductor Field Effect Transistor). The intrinsic diode of such a transistor has the characteristic of being bidirectional in current.

The switches make it possible to operate the electric machine either in a motor mode from a battery supplying electrically an on-board network of the vehicle, or in an alternator mode to supply the on-board network and recharge the battery of the vehicle. In the case of an electric machine comprising three stator phases, the voltage converter comprises three low-side switches each connected to one of the three phases and to ground and three high-side switches each connected to one of the three phases and to a terminal positive of the on-board network battery of the motor vehicle.

In certain phases of the motor vehicle's life, the electrical machine is required to be at rest in a "passive" state, known as the "idle" state. This "passive" state is implemented when the desire of a traction chain supervision computer is not to supply power to the electrical network or not to draw mechanical power, or in the event of a machine fault rotating electric.

However, an electric machine having a rotor equipped with permanent magnets has the particularity of having a constant presence of magnetic flux. Consequently, if the machine is driven in rotation during its operation in "passive" mode, this generates the creation of an electromotive force (or EMF). Depending on the value of this EMF, the "passive" mode can lead to controlling the power inverter in different ways.

When the rotational speed of the electric machine is low, the electric machine is controlled in an open mode, also called OC mode (for "Open Circuit") in which the switches are open. This mode of operation is acceptable as long as the electromotive force generated by the electrical machine remains below the voltage of the vehicle's electrical network. On the other hand, when the electromotive force of the electrical machine becomes greater than the voltage of the electrical network, an uncontrolled current can be injected by the electrical machine into the electrical network of the vehicle, which represents a security risk.

To avoid this, the control module of the electric machine monitors the electromotive force or the rotational speed which is also a representative value of the electromotive force.

When the electromotive force or the speed of rotation reaches a threshold that risks causing the injection of an uncontrolled current, the electrical machine is controlled in an ASC short-circuit mode also called ASC mode (for "Active Short Circuit" in English) in which all electronic switches of the inverter are in the closed state. Such a mode of operation generates a parasitic torque on the shaft of the electric machine which must be compensated by the heat engine which then consumes significant mechanical energy for this purpose.

The invention aims to effectively remedy this drawback by proposing a method for controlling a rotating electrical machine integrated in a hybrid traction chain of a motor vehicle, said rotating electrical machine comprising a rotor with permanent magnets and a plurality of phases electrically connected to an inverter provided for each phase with a switching arm having a high-side electronic switch and a low-side electronic switch,
- said method comprising, when the rotating electrical machine is in a passive state:
- a step of controlling the rotating electrical machine in an open circuit mode in which the electronic switches of the inverter are open, and
- a step of controlling the electric machine in a short-circuit mode in which the electronic switches of the inverter are in the closed state,
- said method further comprising a step of controlling the electric machine in an intermediate mode of energy optimization in which an overall energy consumption of the traction chain is reduced compared to the short-circuit mode,
- a passage from the open circuit mode to the intermediate mode of energy optimization occurring when a first switching criterion is fulfilled, and a passage from the intermediate mode of torque compensation to the short-circuit mode occurring when a second switching criterion is full.

The invention thus makes it possible, thanks to the introduction of the intermediate operating mode, to delay the passage to the short-circuit mode in which the heat engine alone compensates for the parasitic torque of the shaft of the electric machine, while obtaining neutrality mechanical vis-à-vis the operation of the combustion engine from which no torque is taken and/or electrical neutrality on the on-board network.

According to an implementation of the invention, the first tilting criterion is a criterion of rotational speed of the rotating electrical machine or a criterion of electromotive force generated by the rotating electrical machine.

According to one aspect of the invention, in the intermediate energy optimization mode, the rotating electrical machine can be controlled by torque regulation at a substantially zero value, or the rotating electrical machine can be controlled by voltage regulation at a reference value, or the rotating electrical machine can be controlled by current regulation at a reference value of current drawn by the rotating electrical machine.

According to an implementation of the invention, in the intermediate energy optimization mode, the rotating electrical machine is controlled by torque regulation at a substantially zero value so as to compensate for a parasitic torque generated on the shaft of the machine electric due to rotation of the permanent magnet rotor.

In this embodiment, the torque is maintained substantially zero by consuming low energy on the battery. The mechanical impact is reduced. This advantageously optimizes overall energy consumption. The current taken from the battery during this transient phase can be maintained within a predefined range.

According to an implementation of the invention, the second switching criterion is a current consumption criterion of the rotating electrical machine.

According to one implementation of the invention, in the intermediate energy optimization mode, the rotating electrical machine is controlled by voltage regulation at a reference value.

This embodiment makes it possible to obtain a good compromise between electrical neutrality and mechanical neutrality. This embodiment makes it possible to maintain the state of charge of the battery.

According to one implementation of the invention, the reference value is substantially equal to a voltage value of an on-board network of the motor vehicle.

According to one implementation of the invention, the second tilting criterion is a torque criterion of the rotating electrical machine.

According to one implementation of the invention, in the intermediate energy optimization mode, the rotating electrical machine is controlled by current regulation at a reference value of current drawn by the rotating electrical machine.

This embodiment makes it possible to obtain electrical neutrality. The electric machine is in this mode slightly in generator mode in order to compensate for these losses. This embodiment has no impact on the state of charge of the battery. The torque impact at the level of the vehicle in this embodiment is negligible.

According to an implementation of the invention, the current reference value is a substantially zero current.

According to one implementation of the invention, the second tilting criterion is a torque criterion.

According to one aspect of the invention, the rotor is a permanent magnet machine without external excitation. As a variant, the rotor may comprise an excitation winding. The rotor may be a claw rotor. The rotor may be a wound rotor which also includes permanent magnets.

The present invention will be better understood and other characteristics and advantages will become apparent on reading the following detailed description comprising embodiments given by way of illustration with reference to the appended figures, presented by way of non-limiting examples, which may be used to complete the understanding of the present invention and the presentation of its realization and, if necessary, contribute to its definition:

There is a schematic representation of different possible configurations of a hybrid traction chain implementing the method according to the invention;

There is a schematic representation of a rotating electric machine and its inverter implementing the control method according to the invention when the electric machine is in a passive state;

There is a diagram of the different modes of operation of the rotating electrical machine during the implementation of the control method according to the invention;

FIGS. 4a to 4c are functional diagrams of different types of control of the rotating electrical machine in the intermediate energy optimization mode;

There is a graphical representation illustrating the difference in energy consumption between the short-circuit operating mode and the energy consumption optimization mode introduced in the method according to the invention.

Identical, similar or analogous elements retain the same reference from one figure to another.

There shows different configurations of a traction chain 10 of a motor vehicle comprising a heat engine 11 associated with a rotating electrical machine 12 able to operate in a motor mode in order to ensure the traction of the motor vehicle and in an alternator mode so as to recharge a on-board network battery, in particular during a regenerative braking phase.

In a so-called "P0" type configuration, the electric machine 12 is mechanically connected to the heat engine 11 via an accessory belt which also drives other ancillary elements of the heat engine, such as a water pump or a air conditioning compressor

In a so-called "P1" type configuration, the electric machine 12 is mechanically connected to the heat engine 11 on the side of the crankshaft 13.

In a so-called "P2" type configuration, the electric machine 12 is arranged downstream of a clutch 15 so as to be able to be decoupled from the heat engine 11 in a pure electric driving mode. The electric machine 12 may or may not be integrated into a gearbox 16.

In a so-called "P3" type configuration, the electric machine 12 is mechanically decoupled from the heat engine 11. The electric machine 12 has a rotational speed that is multiple of that of the heat engine 11.

In a so-called "P4" type configuration, the electric machine 12 can be installed on the front wheel set 17.1 or the rear wheel set 17.2 of the motor vehicle. The implantation may be carried out by means of a coupling device 18, for example a dog clutch device, capable of selectively coupling or uncoupling the electric machine with respect to the wheels of the vehicle.

As can be seen on the , an inverter 20 is connected to the phases of an electric machine 12 with a permanent magnet rotor. The inverter 20 comprises a plurality of switching arms 21.1, 21.2, 21.3 electrically connected in parallel. Each switching arm 21.1, 21.2, 21.3 comprises a high side switch 22 and a low side switch 23 connected to each other at a midpoint, each midpoint being intended to be connected to at least one phase u , v, w of an electric machine 12. In the example of the , the electric machine has three phases u, v, w (and three corresponding bridge arms). As a variant, the electric machine 12 could comprise any number of phases, in particular 5 phases for a five-phase configuration or 6 phases for a 6-phase or double-three-phase configuration.

An electric machine control module 12 controls the opening or closing of each switch 22, 23 to control the power supply to the electric machine 12. The low side switches 23 or the high side switches 22 are electronic switches of power supply, for example of the metal-oxide field effect transistor type, also known by the acronym MOSFET (Metal Oxide Semiconductor Field Effect Transistor). The intrinsic diode 25 of such a transistor has the characteristic of being bidirectional in current.

The switches 22, 23 make it possible to supply the phases u, v, w of the stator, either in a motor mode from a battery 26 electrically supplying an on-board network of the vehicle, or in an alternator mode to supply the network of edge and recharge the battery 26 of the vehicle. In the case of an electric machine 12 comprising three stator phases, the inverter 20 comprises three low side switches 23 each connected to one of the three phases u, v, w and to ground and three high side switches 22 each connected to one of the three phases u, v, w and to a positive terminal of the battery 26 of the on-board network of the motor vehicle.

In certain phases of life of the motor vehicle, the electrical machine 12 is required to be at rest in a "passive" state, called an "idle" state. This "passive" state is implemented when the desire of a traction chain supervision computer 10 is not to supply power to the electrical network or not to draw mechanical power, or in the event of a fault in the electric machine 12.

As illustrated by the , when the electric machine 12 is in the passive state, the electric machine 12 is controlled in the open circuit mode or OC mode (for "Open Circuit" in English) in which the electronic switches 22, 23 of the inverter 20 are open. The control of the electric machine 12 in open circuit mode OC is carried out until a first switching criterion Crit_1 is fulfilled. The first switching criterion Crit_1 is a rotational speed criterion of the electric machine 12 or an electromotive force criterion generated by the electric machine 12. The speed criterion is defined for example by a rotational speed of the electric machine 12 comprised between 3000 and 5000 rpm. Alternatively, the switching criterion Crit_1 is defined by an electromotive force comprised for example between 20 and 50 Volts.

When the first switching criterion Crit_1 is fulfilled, the electric machine 12 is controlled in an intermediate mode of energy optimization INT in which an overall energy consumption of the traction chain 10 is reduced compared to the short-circuit mode ASC also called mode ASC (for Active Short Circuit in English) in which all the switches 22, 23 are closed. The overall energy consumption of the traction chain 10 is all of the energy consumed by the traction chain 10 in operation corresponding to the sum of a mechanical energy consumed by the heat engine 11 and an electrical energy consumed by the electric machine 12.

As explained in more detail below, in the intermediate energy optimization mode INT, the electric machine 12 can be driven by torque regulation at a substantially zero value so as to compensate for a parasitic torque generated on the shaft. of the electric machine 12 due to a rotation of the permanent magnet rotor. By “substantially zero torque value”, is meant a zero torque value or in any case less than a few Newton meters, in particular less than 1 N.m or 2 N.m.

Alternatively, the electric machine 12 is controlled by voltage regulation at a reference value which is preferably substantially equal to the voltage value of the on-board network of the motor vehicle. "Voltage substantially equal to the voltage value of the on-board network" means a voltage equal to the voltage of the on-board network or a voltage having a difference of only a few volts, in particular 1 to 2 volts, with respect to the voltage of the on-board network. The voltage of the on-board network depends on the vehicle and may be between 24 Volts and 56 Volts, and in particular equal to 48 Volts.

Alternatively, in the intermediate energy optimization mode INT, the electric machine 12 is controlled by current regulation at a reference value of current drawn by the electric machine 12 from the vehicle's on-board network. Preferably, the reference value is a substantially zero current. By "substantially zero current" is meant a zero current or in any case less than a few amperes, in particular less than 1 ampere or 2 amperes.

The control of the electric machine 12 in the intermediate energy optimization mode INT is carried out until a second switching criterion Crit_2 is fulfilled. This second switching criterion Crit_2 depends on the selected control of the electric machine 12.

In the case of torque control of the electric machine 12, the second switching criterion Crit_2 is a current consumption criterion of the electric machine 12 (and therefore a current consumption criterion taken from the on-board network of the vehicle ). This current consumption criterion is defined for example by a current comprised between 30A and 100A and preferably being of the order of 50A. By "of the order of" is meant a variation of plus or minus 10% with respect to the value indicated.

In the case of a voltage control of the electric machine 12 at a voltage value substantially equal to the voltage of the on-board network or a current control of the electric machine 12 at a current value substantially zero, the second switching criterion Crit_2 is a torque criterion of the electric machine 12. This torque criterion is for example defined by a torque of the order of plus or minus 3 N.m. This torque value has the advantage of having a low impact on the consumption of the thermal engine 11 and of not disturbing driving pleasure.

When the second switching criterion Crit_2 is fulfilled, the electrical machine 12 is controlled in the ASC short-circuit mode in which all the electronic switches 22, 23 of the inverter 20 are in the closed state.

There shows a functional diagram of the control of the electric machine 12 by a torque regulation at a substantially zero torque.

A module for managing the electric machine M1 makes it possible to define, from the setpoint torque C* (here equal to 0), setpoint currents Id*, Iq* in the Park frame.

A current control module M2 defines corresponding reference voltages Vd*, Vq* in the Park frame.

A voltage modulation module M3 defines phase voltage duty cycles RC sent to the inverter 20 electrically connected to the battery 26 of the on-board network. The inverter 20 then controls the rotary electrical machine 12 in a motor mode.

A current sensor makes it possible to return the actual current values Id, Iq to the current control module which can adapt the setpoint voltages Vd*, Vq* accordingly.

A system 28 for monitoring the position of the rotor of the electric machine 12 makes it possible to determine a position Pr as well as a speed of rotation Wr of the rotor. These values Pr, Wr are communicated to the management module of the electric machine 12. The monitoring system 28 may include in particular a Hall effect sensor or any other equivalent sensor suitable for the application,

There shows a functional diagram of the control of the electric machine 12 by voltage regulation at a voltage substantially equal to the voltage of the on-board network of the motor vehicle. Compared to the diagram of the , a voltage regulation module 29 is introduced which compares the setpoint voltage Vdc* corresponding to the optimum operating voltage of the onboard network with the actual voltage Vdc of the onboard network and determines a corresponding torque setpoint C*.

There shows a functional diagram of the control of the electric machine 12 by current regulation at a substantially zero current. Compared to the diagram of the , a current regulation module 30 is introduced which compares the setpoint current Idc* (in our case substantially zero) with the actual current Idc delivered by the on-board network and determines a corresponding torque setpoint C*.

There demonstrates that when the electric machine 12 is in a passive state, the electric power P consumed by the electric machine 12 in the intermediate mode INT based on regulation at zero torque (cf. curve C1) is lower than the mechanical power P consumed by the heat engine 11 when the electric machine 12 operates in the ASC short-circuit mode (cf. curve C2). This reduction in energy consumption is observable over the entire Wr speed of the electric machine 12.

Of course, the different features, variants and/or embodiments of the present invention can be associated with each other in various combinations insofar as they are not incompatible or exclusive of each other.

Furthermore, the invention is not limited to the embodiments described above and provided solely by way of example. It encompasses various modifications, alternative forms and other variants that a person skilled in the art may consider in the context of the present invention and in particular all combinations of the various modes of operation described previously, which may be taken separately or in combination.

Claims (10)

Method for controlling a rotating electric machine (12) integrated in a hybrid traction chain (10) of a motor vehicle, said rotating electric machine (12) comprising a rotor with permanent magnets and a plurality of phases (u, v, w ) electrically connected to an inverter (20) provided for each phase with a switching arm (21.1, 21.2, 21.3) having a high side electronic switch (22) and a low side electronic switch (23),
- said method comprising, when the rotating electrical machine (12) is in a passive state:
- a step of controlling the rotating electrical machine (12) in an open circuit mode (OC) in which the electronic switches of the inverter (20) are open, and
- a step of controlling the electric machine (12) in a short-circuit mode (ASC) in which the electronic switches of the inverter (20) are in the closed state,
characterized in that said method further comprises a step of controlling the electric machine (12) in an intermediate energy optimization mode (INT) in which an overall energy consumption of the traction chain (10) is reduced compared to the short-circuit mode (ASC),
- a change from open circuit mode (OC) to intermediate energy optimization mode (INT) occurring when a first switching criterion (Crit_1) is met, and a change from intermediate torque compensation mode to short-circuit mode (ASC) occurring when a second failover criterion (Crit_2) is met. Method according to Claim 1, characterized in that the first tilting criterion (Crit_1) is a criterion of rotational speed of the rotating electrical machine (12) or a criterion of electromotive force generated by the rotating electrical machine (12). Method according to Claim 1 or 2, characterized in that, in the intermediate mode of energy optimization (INT), the rotating electrical machine (12) is controlled by a torque regulation at a substantially zero value so as to compensate for a torque noise generated on the shaft of the electric machine (12) due to rotation of the permanent magnet rotor. Method according to Claim 3, characterized in that the second switching criterion (Crit_2) is a current consumption criterion of the rotating electrical machine (12). Method according to Claim 1 or 2, characterized in that, in the intermediate energy optimization mode (INT), the rotating electrical machine (12) is controlled by voltage regulation at a reference value. Method according to Claim 5, characterized in that the reference value is substantially equal to a voltage value of an on-board network of the motor vehicle. Method according to Claim 5 or 6, characterized in that the second tilting criterion (Crit_2) is a torque criterion of the rotating electrical machine (12). Method according to Claim 1 or 2, characterized in that, in the intermediate mode of energy optimization (INT), the rotating electrical machine (12) is controlled by a current regulation at a reference value of current drawn by the machine rotary electric (12). Method according to Claim 8, characterized in that the current reference value is a substantially zero current. Method according to Claim 8 or 9, characterized in that the second tilting criterion (Crit_2) is a torque criterion.