INSTRUMENTATION AND CONTROL METHOD FOR AN ELECTRIC LATHE FOR A MOTOR VEHICLE

Description

[0001] The present invention relates to a method for controlling a rotating electrical machine of a motor vehicle.

[0002] The invention relates more particularly to a method for controlling a rotating electrical machine making it possible to recover part of the kinetic energy of the vehicle during braking or slowing down phases and to convert it into electrical energy.

[0003] The present invention finds a particularly interesting application in the field of alternators or alternator-starters for motor vehicles.

[0004] New CO2 emission control standards now require more efficient management of the vehicle's electrical system. As a result, car manufacturers are looking for innovative solutions to help transition to cleaner vehicles.

[0005] In the field of motor vehicles, it is now known to decouple the rotating electrical machine (i.e. the alternator) from the engine during acceleration phases and to couple it again during braking phases to brake the vehicle more and / or to transform part of the kinetic energy of the engine into electrical energy, in particular to recharge the vehicle's battery.

[0006] This mode of energy recovery during braking phases is classically called regenerative or regenerative braking.

[0007] Document WO 2015 / 018993 describes a device for controlling regenerative braking of a vehicle equipped with a first braking means and a second braking means and designed to generate a regenerative braking instruction as a function of a braking request signal from a driver's pedal of the vehicle. Documents US 2006 / 192533 A1, EP 2 039 559 A1 and US 2006 / 142115 A1 also disclose regenerative braking techniques.

[0008] In this context, the invention seeks to propose an innovative solution for managing the alternator during regenerative braking, optimizing both the recharging of the vehicle battery while avoiding excessive use of the voltage regulation means.

[0009] To this end, the invention proposes a method for controlling a rotating electrical machine, as defined in independent claim 1.

[0010] In addition to the characteristics which have just been mentioned in the preceding paragraph, the control-command method according to the invention may have one or more additional characteristics among the following, considered individually or according to all technically possible combinations: the step of flow of the predetermined excitation current is limited in time by a maximum activation duration adjustable by programming according to the system needs and constraints (temperature, battery, reliability, etc.); the method comprises a step of blocking for a determined duration the flow of the excitation current of the regenerative braking function predetermined by the voltage regulator; said blocking step occurs at the end of the step of flow of a predetermined excitation current; the maximum activation duration during which the predetermined excitation current is flowed increases with the increase in the average excitation current flowed by the rotating electrical machine.

[0011] The invention also relates to a rotating electrical machine as defined in independent claim 5.

[0012] Advantageously, the rotating electrical machine includes a temperature sensor.

[0013] Advantageously, the temperature sensor is a diode with a "thermocoupled" thermal measurement connected to the voltage regulator. Advantageously, a Hall effect sensor makes it possible to give an estimate of the flow current which makes it possible to deduce the diode temperature via the phase voltage value information + machine current and a map integrated into the regulator.

[0014] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. The figures are presented for information purposes only and in no way limit the invention. figure 1 illustrates the interaction between the rotating electrical machine, the motor control box and the battery of a motor vehicle during regenerative braking. figure 2 illustrates a block diagram illustrating the main steps of the control method according to the invention. The figure 3 illustrates a first example of operation of the control-command method according to the invention during a first braking scenario. The figure 4 illustrates a second example of operation of the control-command method according to the invention during a second braking scenario. The figure 5 illustrates a third example of operation of the control-command process during the third braking scenario illustrated previously in figure 4 .

[0015] There figure 1 illustrates the interaction between different elements of a motor vehicle during a regenerative braking phase with management carried out by the control-command method according to the invention. Conventionally, a motor vehicle comprises, in particular, an electronic control unit 2, known by the abbreviation ECU (for “Engine” Electronic Control Unit in English) electrically connected to the rotating electrical machine 1 which is directly connected to a battery 3.

[0016] Typically, the electronic control unit 2 constantly receives information about the vehicle status as well as the status of the various driver controls via various sensors present in the vehicle. The electronic control unit 2 is also capable of controlling numerous actuators based on the vehicle status information.

[0017] Thus, the electronic control unit 2 receives a large amount of information, including information on the operation of the brake pedal or on the slowing down of the vehicle.

[0018] The rotating electrical machine 1 is typically a motor vehicle alternator, for example a claw alternator, comprising a voltage regulator 11 and an electronic module 12 capable of rectifying, regulating and controlling the quantity of current delivered to the battery 3, in particular as a function of the voltage information U batt of the battery 3.

[0019] There figure 2 illustrates the main steps of the control-command method 100 according to the invention.

[0020] According to a first step 101 of the method 100, the voltage regulator 11 receives information, referenced “info_freinage” on the braking state of the motor vehicle. By vehicle braking, we mean both an action by the driver consisting of actuating the brake pedal and a slowing down of the vehicle when the driver no longer actuates the accelerator pedal.

[0021] This “braking_info” information is sent continuously by the electronic control unit 2 to the voltage regulator 11. This “braking_info” information is typically information using binary numbering coding on one or more bits, for example “0” means that the vehicle is not braking and “1” that the vehicle is braking. This information is represented by the graphs (b) on the figures 3 à 5 This information corresponds, in binary coding, to the different braking periods carried out by the driver during the scenarios represented in graphs (a) which illustrate the vehicle speed as a function of time.

[0022] During a second step 102, when the voltage regulator 11 detects a change in state of the braking information “info_freinage”, and more specifically a change in state from “0” to “1”, the voltage regulator 11 triggers a timer (graphs (c)) at time t 0 .

[0023] In a third step 103, occurring simultaneously with the second step 102, when the change of state is detected by the voltage regulator 11, the latter authorizes the alternator 1 to deliver or output a maximum current C MX . This step is notably illustrated by the graphs (d) which illustrate the quantity of current output by the alternator 1 as a function of time. The output of an excitation current is carried out during the duration td which corresponds, in the embodiment illustrated in figure 3 , entirely during the vehicle braking phase.

[0024] The maximum current C MX corresponds to the maximum current that alternator 1 is technically capable of delivering.

[0025] During this third step, the maximum current flow duration is limited by a maximum activation duration T dmax which is counted from the triggering of the timer at time t 0 . More precisely, the voltage regulator 11 authorizes a current flow as long as the duration of the braking phase is less than the maximum activation duration T dmax set in the voltage regulator 11. Thus, when the braking phase has a duration greater than the maximum activation duration T dmax then, the voltage regulator 11 authorizes the flow of a maximum excitation current only during the period of time corresponding to the maximum activation duration T dmax .

[0026] In a fourth step 104, the voltage regulator 11 blocks, for a certain duration tb, the possibility of delivering a maximum excitation current during a new braking phase. This blocking occurs at the end of a current flow period td occurring during a previous braking phase.

[0027] This blocking allows a rest period tb to be imposed during which it is impossible for the alternator to deliver a maximum excitation current again during a new braking phase. This rest or blocking period ensures sufficient cooling of the components, particularly the rectifier diodes / Mosfet and the voltage regulator.

[0028] According to a first embodiment, this rest duration tb is fixed and configurable in the electronic module 12 of the voltage regulator 11 according to the characteristics of the alternator 1.

[0029] According to an alternative embodiment, this rest duration tb can be configured as a function of the duration of the excitation current flow during the previous braking. Thus, if during a previous braking, the duration of the excitation current flow was less than the maximum activation duration, then the voltage regulator 11 can authorize a new excitation current flow phase by taking into account the different characteristics (time, power) of the previous current flow phase during regenerative braking.

[0030] According to a second embodiment illustrated more specifically in the figure 4 , it is also possible to variably set the maximum activation time t dmax during which the excitation current is at its maximum and allows alternator 1 to deliver a maximum current C MX .

[0031] In this first embodiment, this maximum activation duration T dmax is configurable according to the average current output by the alternator before a regenerative braking phase. Thus, if the alternator 1 is in a high thermal state following a significant flow rate beforehand, for example due to the electrical consumption of various components present in the vehicle, then it is possible to adjust this maximum activation duration T dmax2 compared to a default value T dmax1 which has a shorter duration. The default value T dmax1 corresponds for example to the maximum activation duration when the alternator 1 is in a “cold” state with very little current flow beforehand. Thus, in general, the maximum activation duration T dmax increases with the increase in the average excitation current output by the alternator 1.

[0032] According to a third embodiment not claimed and illustrated more specifically in the figure 5 , it is also envisaged to variably parameterize the activation duration T dmax directly as a function of the temperature of the critical components such as the diodes or the regulator 11. In this embodiment, the maximum activation duration of the alternator is limited by the temperature of the critical components. Thus, as soon as the temperature of the critical components reaches a value equal to a critical setpoint temperature, the regulator 11 stops the flow of excitation current. The curve (g) of the figure 5illustrates an example of variation in the temperature of critical components as a function of time, during a speed variation scenario illustrated by curve (a). Thus, during the third braking, the activation duration is limited by the increase in temperature which becomes equal to the temperature setpoint value T cons . This temperature information is received directly by the regulator via a temperature probe, or a system allowing the acquisition of the temperature of critical components such as for example a thermocouple positioned on a rectifier diode, or a system allowing the temperature to be estimated via a Hall effect sensor to know the flow current of the machine, a measurement of the phase voltage as well as a mapping of the voltage drop of the diodes or rectifier devices in the regulator.

[0033] This third embodiment of the control-command method 100 makes it possible in particular to save time for recovering electrical energy during regenerative braking by taking into account the temperature of the components.

Claims

1. Command and control method (100) for the command and control of a rotary electric machine (1) for a motor vehicle which makes it possible to recover some of the kinetic energy of the vehicle during braking or deceleration phases and to convert it into electrical energy, said rotary machine (1) comprising a voltage regulator (11), said method comprising: - a reception step (101) of continuous receipt of information concerning a phase of regenerative braking of said vehicle, - a delivery step (103) of delivery of a predetermined excitation current by said voltage regulator (11) during this regenerative-braking phase, the step of delivery of the predetermined current being limited in time by a maximum activation time (Tdmax), characterized in that the maximum activation time (Tdmax) during which the predetermined excitation current is delivered is a function of the mean excitation current delivered by the rotary electric machine (1) before a regenerative-braking phase.

2. Command and control method (100) according to the preceding claim, characterized in that it comprises a blocking step (104) of blocking the delivery of the predetermined excitation current by the voltage regulator (11) for a determined length of time (tb).

3. Command and control method (100) according to the preceding claim, characterized in that said blocking step (104) occurs immediately after the end of the delivery step (103) of delivering an excitation current.

4. Command and control method (100) according to any one of the preceding claims, characterized in that the maximum activation time (Tdmax) during which the predetermined excitation current is delivered increases with increasing mean excitation current delivered by the rotary electric machine (1).

5. Rotary electric machine (1) comprising means for performing a regenerative braking function in a motor vehicle, characterized in that it comprises a voltage regulator (11) implementing the method according to any one of the preceding claims.

6. Rotary electric machine according to Claim 5, characterized in that it comprises a temperature sensor (12).

7. Rotary electric machine (1) according to Claim 6, characterized in that the temperature sensor (12) is a diode having a thermal measurement connected to the voltage regulator (11).

8. Rotary electric machine (1) according to Claim 6, characterized in that the temperature sensor (12) consists of a hall effect sensor able to provide an estimate of the delivered current in order to derive the temperature therefrom.