RU2807179C2 - Method for regulating on-board network of vehicle - Google Patents

Abstract

FIELD: vehicles; on-board networks.

SUBSTANCE: group of inventions relates to a method for regulating an on-board network and a vehicle. The method for regulating the on-board network of a vehicle includes the stages of: detecting commands for charging or discharging batteries; adapting the set point (vc) for adjusting the generator voltage so as to charge or discharge the batteries; maintaining the state of charge of the batteries in the absence of a charging command and a discharging command. In order to charge the batteries, the voltage regulation set point (vc) is increased until the measured value (ib) of the battery current is less than the maximum value (imax) of the charging current.

EFFECT: control of on-board network voltage is achieved by controlling electrical power using a generator and discharging batteries.

8 cl, 6 dwg

Description

The invention relates to a method for regulating the on-board network of a vehicle and to the on-board network in which the method is carried out.

Regulation of the vehicle on-board network is usually carried out on the voltage obtained at the level of the main distribution, that is, at the terminals of the battery (the main battery in the case of a network with several batteries). This regulation provides a voltage range compatible with the requirements of electrical consumers and with battery charging. Nowadays, there is an increasing need to quickly recharge the battery. In the case of a network with several batteries, it is possible to select specific criteria for each battery and generalize, taking into account all needs. Increasingly, there is also a need to monitor voltage during intentional battery discharge (typically an alternator discharge to utilize energy previously recovered during deceleration). Recharging lithium-ion batteries or supercapacitors is a typical case of this new regulation need, since these storage media can be charged with currents much higher than the charging currents of a lead-acid battery and can change the overall control of the on-board network, while the technical problem being solved is constant monitoring the voltage of the on-board network while simultaneously controlling electrical power using a generator and discharging one or more batteries of any type (lead-acid, lithium-ion, supercapacitor).

Document FR2803253 discloses, for example, a method for storing electricity for a hybrid vehicle. The document also discloses a method for regulating the on-board network, which can charge the battery. However, the disadvantage of the only criterion provided for current limitation and based on a simple energy recovery strategy is that it does not take into account other events other than energy recovery, for example in the deceleration phase. If in a particular case the battery is discharged abnormally and the environment under the hood is a little warm, the document mentioned does not provide anything to limit the current in the wires and at the same time provide better charging of the battery.

To solve the problem facing the known solutions, the invention proposes a method for regulating the on-board network of a vehicle, comprising the steps of detecting a charging command for one or more batteries and detecting a discharge command for each battery.

The method is characterized in that it comprises the steps of adapting the generator voltage regulation setpoint so as to charge one or more batteries if a charge command is detected, adapting the generator voltage regulation setpoint so as to discharge the battery or batteries if a discharge command is detected , and maintaining a state of charge of the specified battery or batteries in the absence of a charge command and a discharge command.

In particular, in order to charge said battery or batteries, the method comprises increasing said voltage control setpoint until the measured current value of said battery or batteries is less than a maximum charging current value.

In particular, the method comprises a step in which the voltage regulation set value is stopped increasing if the on-board network voltage reaches the maximum permissible voltage.

In particular, the method includes a step in which the voltage regulation set value is reduced if the measured value of the battery current is not lower than the maximum charging current value.

In particular, to discharge the battery or batteries, the method comprises decreasing the voltage control setpoint until the measured current value of each battery exceeds a negative minimum discharge current value.

In particular, the method includes the step of stopping decreasing the voltage regulation set value if said voltage regulation set value reaches a minimum acceptable value.

In particular, the method comprises increasing the voltage regulation set value if the measured current value of each battery does not exceed a minimum discharge current value.

The invention also relates to an on-board vehicle network comprising at least one battery, a generator, an on-board computing device and a memory containing a program with computer commands that control the claimed method when said program is executed by the on-board computing device.

The invention also relates to a motor vehicle containing the above-mentioned on-board network.

Other advantages and features of the invention will become more apparent from the following detailed description of embodiments and embodiments, presented as illustrative and non-limiting examples, with reference to the accompanying drawings, in which:

Fig. 1 is a schematic view of an on-board network with one battery in which the invention is implemented.

Fig. 2 is a schematic view of an on-board network with two batteries in which the invention is implemented.

Fig. 3 - main stages of the claimed method.

Fig. 4 - stages of the charging cycle within the framework of the claimed method.

Fig. 5 - stages of the discharge cycle within the framework of the claimed method.

Fig. 6 illustrates the possible behavior of the on-board network as a result of implementing the claimed method.

In fig. 1 shows the on-board network of a vehicle in which the invention is implemented. The on-board network shown contains a battery 1 with a nominal DC voltage of 12 V or 48 V. A low battery voltage of less than 100 V allows the battery pole, for example the negative pole, to be connected to the vehicle ground without risk to the vehicle user. The other pole, for example the positive pole of the battery, is connected to the rectified positive pole of a current generator 11 such as an alternator or starter-generator. The battery 1 and the generator 11 form a current source for powering a set of 12 electrical consumers, for example, but not limited to, including electromechanical drives, lighting and alarm elements, electronic control circuits, including an on-board computing device 10 containing a computer program in memory with commands for implementing the method presented below, when the commands are executed by the on-board computing device 10.

The on-board computing device 10 also measures the value v _b of the on-board network voltage using a voltage sensor 8, preferably at the output of the battery 1. The on-board computing device 10 measures the value i _{1 of} the current in the battery 1 using a current sensor 3. The discharge of battery 1 determines the negative value i ₁ of the current. Charging battery 1 determines the positive value i ₁ of the current. The on-board computer 10 generates a voltage control setpoint v _c of the generator 11 based on the measured current value i ₁ by performing the method described below in real time.

In fig. 2 shows another vehicle on-board network, which is different from the on-board network shown in FIG. 1, in that it contains a second battery 2. When batteries 1 and 2 are connected or can be connected in parallel to the on-board network, as shown in FIG. 2, the battery 2 has a rated constant voltage identical to the rated constant voltage of battery 1. The on-board computer 10 generates the voltage control setpoint _vc of the generator 11 by real-time implementation of the method described below based on the current value i _b equal to the sum of the measured value i ₁ current and the value i ₂ of the current flowing in the battery 2, measured using a current sensor 4. If battery 2 is disconnected from the on-board network, for example, using a switch (not shown), the value i ₂ of the current flowing in battery 2 is zero, and the value i _b of the battery current is equal to the value i ₁ of the current flowing in battery 1. Exactly the same However, if battery 1 is disconnected from the on-board network, for example, using a switch (not shown), the value i ₁ of the current flowing in battery 1 is zero, and the value i _{b of} the battery current is equal to the value i ₂ of the current flowing in battery 2.

The number of batteries is not limited to two. The method described below can be carried out using the value i _b of the battery current equal to the sum of the currents flowing into the battery, or by considering each current i ₁ and i ₂ separately and taking into account the most limiting current criteria.

If the rated DC voltage of battery 2 is different from the rated DC voltage of battery 1, the two batteries are not connected directly in parallel as shown in FIG. 2. This may be the case, for example, if battery 1 with a nominal voltage of 12 V is intended to supply a set of 12 so-called dependent electrical consumers, while battery 2 with a nominal voltage of 48 V is intended to provide traction in the micro-hybrid mode of the vehicle and, when necessary, to recharge battery 1 through a DC/DC converter (not shown), which is known in itself. In this case, the on-board computing device 10 or another on-board computing device implements for the battery 2 a second variant of the method, which differs from the first variant of the method for the battery 1. The first variant of the method generates a given value v _c for controlling the voltage of the generator 11, which is an alternating current generator at 12 B, based on the measured value i _b =i ₁ current. The second embodiment of the method generates another voltage control setpoint of another generator (not shown), which is a 48 V starter generator, based on the measured value i _b =i ₂ current.

In fig. Figure 3 shows the main stages of the claimed method. The method begins at task start step 100. Stage 100 is activated immediately when the vehicle exits sleep mode, which occurs when the door is opened and the contact is turned on. In other words, there is a transition from the parking phase to the active phase of the vehicle.

After step 100, at step 101, the condition for completing the task is checked. If the task termination condition is met, the method ends by moving to completion step 106. If the task completion condition is not met, the method proceeds to step 102 of turning on the electrical energy storage cycle. The task completion condition is considered to be met if the vehicle is no longer in use, for example after locking the doors or exiting the vehicle without any user function activated. There is a transition from the active phase to the parking phase of the vehicle.

After step 102 or immediately after step 101, in the absence of an electrical energy storage control loop, the battery charging request is checked at step 103. If there is a battery charging request, the method proceeds to step 110 of enabling a battery charging cycle. The battery charging request is part of another known method and is not within the scope of the invention. For example, another known method is a method for monitoring the state of charge of an SOC battery. Another known method may also be a method for recovering kinetic energy during controlled deceleration phases of the vehicle. In the absence of a battery charging request, the inventive method proceeds to step 104, where the battery discharge request is checked.

If there is a request to discharge the battery, the method proceeds to step 120 of enabling a battery discharge cycle. In this case, the request to discharge the battery is also part of another known method and is not included in the scope of the invention. For example, another known method is a method of monitoring the state of charge of an SOC battery to release charging capacity before subsequent deceleration. Another known method may also be a method for unloading the electrical generator during controlled acceleration phases of the vehicle. In the absence of a battery discharge request, the inventive method proceeds to step 105 of maintaining the battery SOC state of charge.

In the battery SOC state of charge maintenance step 105, the generator voltage control set value _vc is increased if the measured current value i _b is negative, the generator voltage control set value v _c is decreased if the current measured value i _b is positive, and the set value v _c is maintained. control the generator voltage without changing if the measured value i _b of the current is zero.

The method returns in real time from step 105 to step 101.

In fig. 4 shows the stages of the battery charging cycle, which begins at step 111 after step 110.

At step 111, the first criterion is checked, namely that the measured value i _b of the battery current is strictly less than the maximum value i _{max of} the charging current allowed for the battery.

If the measured battery current value i _b is not strictly less than the maximum current value i _max , at step 115 the generator voltage control setpoint v _c is reduced, for example, by a value proportional to the difference between the measured current value i _b and the maximum current value i _max , and /or, for example, to a constant voltage value predetermined in the test phase.

If the measured value i _b of the battery current is strictly less than the maximum value i _max of the current, at step 112 the second criterion is checked, namely, that the measured value v _b of the on-board voltage is strictly less than the maximum permissible value v _max of the on-board voltage, usually equal to 15 V , if the nominal voltage is 12 V.

If the measured value v _b of the on-board network voltage is strictly less than the maximum permissible value v _max of the on-board network voltage, at step 113 the set value v _c of the generator voltage control is increased, for example, by a value proportional to the difference between the maximum value v _max of the voltage and the measured value v _b of the voltage , and/or, for example, to a constant voltage value predetermined in the test phase.

If the measured value v _b of the on-board voltage is not strictly less than the maximum permissible value v _b of the on-board voltage, the completion of charging is checked at step 116, also carried out after steps 113 and 115.

If charging completion is noted at step 116, the cycle returns to the main steps, for example, to step 102. If charging is not completed, the cycle returns to step 111. The charging completion is marked, for example, as a result of a request from another method that controls the exit from the loop charging the battery or batteries. Completion of charging may also be indicated by a battery current monitor and/or a State Of Charge (SOC) monitor. If the current is below the threshold (for example: 2 A) or if the SOC reaches 100%, then the end of charging occurs.

In fig. 5 shows the stages of the battery discharge cycle, which begins at step 121 after step 120.

At step 121, the third criterion is checked, namely, that the measured value i _b of the battery current strictly exceeds the minimum acceptable value i _min of the battery discharge current, for example, equal to -40 A. It can be recalled that the value of the discharge current is negative. The same applies to the minimum permissible value i _min of the discharge current, and, therefore, the check makes sure that the discharge current is less in absolute value (for example, 40 A for one battery or 80 A for two batteries) of the minimum permissible value i _min of the discharge current .

If the measured value i _b of the battery current does not algebraically strictly exceed the minimum value i _min of the current, that is, if the measured absolute value ⏐ _{i b} ⏐ of the battery current is not strictly less than the limiting absolute value ⏐ i _min ⏐ of the current, at step 124 it is verified that the specified value v _c generator voltage control is not lower than the minimum set value v _min voltage control, usually equal to 11.8 V, relative to the nominal value of 12 V.

If, at step 124, the generator voltage control setpoint _vc is not less than the minimum voltage control setpoint _vmin , at step 125, the generator voltage _control setpoint vc is reduced, for example, by a value proportional to the difference between the voltage control setpoint _vc and the minimum value. v _min voltage, and/or, for example, to a constant voltage value predetermined in the test phase.

Step 125 is followed by step 126 of checking the discharge completion command. The discharge completion command occurs, for example, as a result of detection of the battery SOC state of charge below a predetermined threshold, entry into a vehicle deceleration phase, or any other event causing the battery to exit discharge mode.

The end of the discharge, marked at step 126, is the exit of the method from the discharge cycle, for example, returning to the electrical storage control step 102. Otherwise, the loop returns to step 121.

If, at step 124, the generator _voltage control setpoint vc is less than or equal to the minimum voltage control setpoint _vmin , the loop continues with step 126.

If at step 121 the measured value i _b of the battery current does not strictly exceed the minimum value i _min of the current, that is, if the discharge current exceeds in absolute value the value that the battery can withstand, at step 122 it is checked that the measured value v _{b of} the on-board network voltage is strictly less the maximum permissible value _vmax of the on-board network voltage, usually equal to 15 V, if the rated voltage is 12 V.

If the measured value v _b of the on-board network voltage is not strictly less than the maximum permissible value v _max of the on-board network voltage, the discharge cycle continues directly with step 126. Lowering the set value of the generator voltage below the mains voltage is the lever that ensures the operation of the battery.

If at step 122 the measured value v _b of the on-board network voltage is strictly less than the maximum permissible value v _max of the on-board network voltage, the discharge cycle continues with step 123, at which the set value v _c of the generator voltage control is increased. This is a means of limiting the value of the discharge current. For example, going from 12 volts to 12.1 volts to increase the discharge current from minus 50 A to minus 40 A. This is a numerical example that can be done, and, among other things, it depends on the state of charge of the battery. Step 123 then proceeds to step 126.

In fig. Figure 6 shows the observed effect of the method on the on-board network in terms of voltage in the upper part and current in the lower part, changing over time t. In the lower part, a broken solid line shows the current value requested in the on-board network by a set of 12 electrical consumers, a broken line in the form of small dashes shows the measured value i _b of the battery current, a broken line in the form of large dashes shows the current value in the alternator, equal to the sum of the values current requested in the on-board network by a set of 12 electrical consumers, and battery current. In the upper part, a broken solid line shows the measured value v _b of the voltage in the on-board network, a broken line in the form of large dashes shows the set value v _{c of} the voltage control of the alternator.

Before point A or after point D, the on-board network voltage is set by the battery. In the case of a multi-battery network, the voltage is set by the most charged battery or batteries that have a higher no-load voltage.

Between points A and B, the on-board network voltage is set by the alternator (or starter-generator), but is limited to a value that allows it not to exceed the maximum charging current i _max set for the selected battery (or for the sum of charging currents, for example, of all batteries).

Starting from point B, the value i _b of the battery charging current is equal to the maximum value i _max of the charging current. The alternator's set point v _c is gradually increased as the battery charges, in order to maintain the maximum charging current value i _max for as long as possible. Then, when the maximum voltage value is reached at point C, this voltage value is maintained while the battery is charging. The battery charging current decreases with a gradual increase in the SOC state of charge of the battery. Immediately upon leaving the charging zone, the value v _c of the generator control voltage is reduced to ensure the delivery of the consumed current to the on-board network from the previously charged battery. The current supplied by the generator from point A to point D continues to decrease and becomes equal to 0 at point E.

Starting from point E, the consumed current is supplied to the on-board network by the battery, which sets its voltage under the influence of the discharge current. Regulation during the battery discharging phase: During the battery discharging phase, the current supplied by the alternator (or starter-generator) is 0 ampere until the absolute value of the battery discharging current exceeds the minimum i _min current value (for example: 30 amperes). If the minimum value i _min of the current is reached at point F, the alternator (or starter-generator) receives a set value of the boost voltage, allowing it to produce the additional current necessary to fully supply the on-board network with current, without exceeding the minimum value i _min of the discharge current set for battery. Increasing the voltage in step 123 causes the alternator to operate and "unloads" the battery so that the battery is above the maximum discharge threshold. In the graph, starting from F, the set voltage value v _c increases in step 123, the on-board network current comes from the battery with the maximum discharge current and with the generator current, supplemented through the regulation of v _c in step 123. If the on-board network current were reduced, then the current the battery would also decrease, and a transition would occur to steps 124 and then 125, due to the test in step 121, which would take into account that the battery is no longer at its maximum discharge.

Starting from point F', the on-board voltage is set by the generator (or starter-generator) in such a way as to obtain the exact complement required so that the sum of the current i _b current coming from the battery and the current coming from the generator corresponds to the value requested by the on-board network. This equilibrium point can be maintained as long as battery charging allows by adjusting the value of vc _to control the generator voltage, even if the current consumed in the on-board network changes both upward and downward. If the current draw again becomes less than the absolute value of the minimum value i _min of current, you can revert to the generator (or starter-generator) supply of 0 amperes. Both charge-limited and discharge-limited cycles follow each other depending on the driving conditions of the vehicle: this sequence is facilitated by city driving: charging occurs during deceleration phases, usually when approaching a red traffic light, and a discharge phase follows this upon resumption of movement and upon subsequent movement. Thus, monitoring the maximum values of I _charging and I _discharging makes it possible not to reach values that lead to disturbances in the operation of the vehicle (for example, too much engine braking in case of too much recharging) or in the operation of the on-board network (for example, too large a voltage drop simultaneously with draining the battery too quickly). If the vehicle's operating conditions force it to reach the charging or discharging limit, a preset voltage Vcons is set, which leads to a state of maintaining charge when the on-board current supplied by the generator (or starter-generator) and when the battery current tends to 0. Another application of this The regulation strategy consists in choosing the distribution of electrical supply between all sources under several limiting criteria.

It is possible, for example, to force a battery (or batteries) to operate up to a certain threshold of maximum discharge current (eg: 80A) in addition to a generator that can supply current up to its maximum current (eg: 150A). The maximum value of current supplied by the battery is a criterion limiting the overall regulation, which is added to the already existing criterion of the voltage range [minimum, maximum]. In this way, an on-board network is obtained that can supply the vehicle consumers up to a maximum of 230 A (150 A from the generator + 80 A from the battery), observing a certain minimum voltage (for example: minimum 12 V) as long as the battery (or batteries) is capable ) produce the required current up to this minimum voltage.

The above criteria may in turn be linked to other criteria. For example, the maximum allowable value i _max of the charging current to meet the first criterion can be set to a constant value set by the battery manufacturer. It is also possible to store in the memory of the computing device 10 a mapping that gives a change in the maximum current value i _max decreasing from an upper value at the minimum operating temperature to a lower value at the maximum operating temperature. The passage of current through the battery tends to heat the battery due to the Joule effect. Thus, at low temperatures, an increased current value helps to heat the battery. When the temperature under the engine hood is high, it is preferable to limit the current to a lower value to avoid raising the battery temperature too much. The mapping can be obtained by calculation as a function of the vehicle profile and/or by measurements during testing on a prototype vehicle.

Claims (14)

1. A method for regulating the on-board network of a vehicle, including the stages at which: detect (103) a command to charge one or more batteries; detect (104) a command to discharge said battery or batteries; adapting (113, 115) the generator voltage regulation set point (v _c ) so as to charge said battery or batteries if a charging command is detected, adapting (123, 125) said generator voltage regulation set point (v _c ) so as to discharge said battery or said batteries if a discharge command is detected, maintain (105) the state of charge of said battery or batteries in the absence of a charge command and a discharge command, characterized in that, in order to charge said battery or batteries, said voltage regulation set point value (v _c ) is increased (113) until the measured current value (i _b ) of said battery or batteries is less than the maximum value ( i _max ) charging current. 2. The method according to claim 1, characterized in that it contains a step in which it stops (112) increasing the specified set value (v _c ) of voltage regulation if the voltage of the on-board network reaches the maximum permissible voltage. 3. The method according to claim 1 or 2, characterized in that it contains a step in which the specified set value (v _c ) of the voltage regulation is reduced (115), if the specified measured value (i _b ) of the current of the specified battery or specified batteries is not lower than the specified maximum value (i _max ) of the charging current. 4. Method according to one of paragraphs. 1-3, characterized in that in order to discharge said battery or batteries, a step is performed in which said voltage regulation set value (v _c ) is reduced (123) until the measured current value (i _b ) of said battery or batteries exceeds the negative minimum value (i _min ) of the discharge current. 5. The method according to claim 4, characterized in that it comprises the step of stopping (122) decreasing said voltage regulation set value (v _c ) if said voltage regulation target value (v _c ) reaches a minimum permissible value. 6. The method according to claim 4 or 5, characterized in that it contains a step in which the specified set value (v _c ) of voltage regulation is increased (125), if the specified measured value (i _b ) of the current of the specified battery or specified batteries does not exceed the specified minimum value (i _min ) of the discharge current. 7. An on-board vehicle network containing at least one battery (1, 2), a generator (11), an on-board computing device (10) and a memory containing a program with computer commands that control the method according to one of claims. 2-6, when the specified program is executed by the on-board computing device. 8. A vehicle containing an on-board network according to clause 7.

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