JPH11103505A - Device for calculating amount of battery charge of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To calculate an accurate charging amount of a battery, by estimating the amount of charge of a battery based on a battery voltage detection value, and correcting an amount-of-charge operation value with an amount-of-charge estimation value. SOLUTION: A device calculates an amount of charge SOC 1 by integrating a charge/discharge current I of a battery 3, at the same time measures a terminal voltage V of the battery 3 when the charge/discharge current I is 0, and estimates an amount of charge SOC 2 by utilizing that the open terminal voltage of the battery 3 is highly correlated to the amount of charge SOC. Then, the amount of charge SOC 1 that is obtained by integrating the charge/discharge current I and performing operation is corrected by the amount of charge SOC 2 being estimated from the terminal voltage V, thus obtaining an accurate amount of charge SOC. For measuring the terminal voltage V when the charge/ discharge current I is 0, a generation power is adjusted so that the generation power of a generator 2 becomes equal to the consumption power of a motor 6 for driving and the charge/discharge current I of the battery 3 is forced to 0, and then the terminal voltage V is measured in this state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for calculating a charge amount of a battery mounted on a hybrid vehicle.

[0002]

2. Description of the Related Art There is known a series hybrid vehicle in which a generator is driven by an engine to generate electric power and supply electric power to a driving motor and a battery. Attention has been paid to extending the range of electric vehicles. As a device that calculates the state of charge (SOC) of the battery mounted on this series hybrid vehicle,
There has been proposed a method in which the charge / discharge current of a battery is integrated, and the integrated value is added to or subtracted from the charge amount to update the charge amount.

[0003]

However, the conventional battery charge calculating device has a problem that errors in the calculated charge are liable to accumulate since the detection error and the sampling error of the charging / discharging current are also integrated. In order to solve this problem, in electric vehicles, a method is adopted in which the charge amount is reset when charging of the battery is completed by a charger to remove an integration error. Such a method cannot be employed because there is little opportunity for the battery to be charged by the charger.

An object of the present invention is to calculate an accurate charge amount of a battery.

[0005]

[Means for Solving the Problems]

(1) A first aspect of the present invention provides a hybrid including a generator driven by an engine, a chargeable / dischargeable battery, and a traveling motor driven by the generated power of the generator and / or the discharged power of the battery. The present invention is applied to a battery charge calculating device of a vehicle. And a battery current detecting means for detecting a charge / discharge current of the battery;
Charge amount calculation means for calculating the charge amount of the battery by integrating the charge / discharge current detection value of the battery; power consumption detection means for detecting the power consumption of the motor; and Power generation control means for performing control so as to coincide with each other; battery voltage detection means for detecting a terminal voltage of the battery when the charge / discharge current detection value becomes substantially zero during control by the power generation control means; A charge amount estimating means for estimating the charge amount of the battery based on the charge amount; and a charge amount correcting means for correcting the charge amount calculation value based on the charge amount estimated value. The battery charge is calculated by integrating the battery charge / discharge current detection value, the motor current consumption is detected, and the power generated by the generator is controlled so that the power generated by the generator matches the current consumed by the motor. I do. Further, the terminal voltage of the battery when the charge / discharge current detection value becomes substantially zero is detected, and the amount of charge of the battery is estimated based on the battery voltage detection value. Then, the charge amount calculation value is corrected by the charge amount estimation value. According to a second aspect of the present invention, there is provided the hybrid vehicle battery charge calculating device, wherein the power consumption detecting means has a vehicle speed detecting means for detecting a vehicle speed, and estimates a running resistance according to the detected vehicle speed. The power consumption of the motor according to the detected power is detected. (3) In the battery charge calculating device for a hybrid vehicle according to claim 3, the power consumption detecting means includes a motor voltage detecting means for detecting a terminal voltage of the motor, and a motor current detecting means for detecting a current flowing in the motor. The power consumption is detected based on the motor voltage detection value and the motor current detection value. (4) In the battery charge calculating device for a hybrid vehicle according to claim 4, the battery voltage detecting means detects the terminal voltage of the battery a predetermined time after the charge / discharge current detection value becomes substantially zero. Things. (5) In the battery charge calculating device for a hybrid vehicle according to claim 5, the predetermined time is made longer as the rate of decrease of the charge / discharge current detection value is higher. (6) The battery charge calculating device for a hybrid vehicle according to claim 6 is provided with a battery temperature detecting means for detecting the temperature of the battery, wherein the lower the detected battery temperature value, the longer the predetermined time. (7) In the battery charge calculation device for a hybrid vehicle according to claim 7, the charge amount correction means weights the charge amount calculation value and the charge amount estimation value to determine the final charge amount. It is. (8) In the battery charge calculation device for a hybrid vehicle according to claim 8, the charge amount correction means increases the weight of the charge amount calculation value as the average value of the detected charge / discharge currents increases. According to a ninth aspect of the present invention, in the battery charge calculating device for a hybrid vehicle, the charge amount correcting means sets the weight of the charge amount estimation value to be greater as the time interval from the previous charge amount correction time to the current charge amount correction time is longer. It is designed to be larger. (10) In the battery charge calculating device for a hybrid vehicle according to a tenth aspect, the charge amount correcting means sets a predetermined cycle and performs the charge amount correcting operation only once in one cycle.

[0006]

【The invention's effect】

(1) According to the first aspect of the present invention, it is possible to remove a detection error and a sampling error of the charge / discharge current from the charge amount calculated by integrating the charge / discharge current, and to always obtain an accurate charge amount even during traveling. Can be. (2) According to the second aspect of the present invention, the power consumption of the motor can be estimated only by using the vehicle speed detecting means. (3) According to the third aspect of the present invention, accurate motor power consumption can be obtained from the motor voltage and the motor current. (4) According to the inventions of claims 4 to 6, it is possible to obtain an accurate open circuit voltage of the battery by compensating for a delay in voltage change with respect to a current change due to physical properties inside the battery. (5) According to the invention of claims 7 to 9, it is possible to determine an accurate charge amount. (6) According to the tenth aspect, it is possible to reduce the load on the microcomputer that executes the calculation processing of the charge amount.

[0007]

FIG. 1 is a diagram showing the configuration of an embodiment. The engine 1 is a prime mover for driving the generator 2, and an internal combustion engine such as a gasoline engine or a diesel engine is used. The generator 2 is a rotating machine that generates electric power used for running the vehicle and charging the battery 3.
A three-phase alternator or the like is used. The generator controller 4 controls the generated power of the generator 2, converts the generated three-phase AC power into DC power, and supplies the DC power to the motor controller 5 and the battery 3. The motor controller 5 includes an inverter and a control device, converts DC power into AC power, and supplies the AC power to the traveling motor 6. The traveling motor 6 is a rotating machine serving as a traveling drive source of the vehicle, and a three-phase synchronous motor or a three-phase induction motor is used. The battery 3 is a battery for supplying power to the traveling motor 6, and is charged by the generated power from the generator 2 and the regenerative power from the motor 6.

The vehicle controller 8 includes a microcomputer and its peripheral parts, controls on-vehicle devices such as the engine 1, the generator controller 4 and the motor controller 5, and executes a control program to be described later to charge the SOC 3 of the battery 3. Is calculated. The vehicle controller 8 includes a voltage sensor 9 for detecting a terminal voltage V of the battery 3 and a charge / discharge current I
, A vehicle speed sensor 11 for detecting the traveling speed VS of the vehicle, a display 12 for displaying the state of charge SOC, and the like.

In this embodiment, the charge amount SOC1 is calculated by integrating the charge / discharge current I of the battery 3, and the charge / discharge operation is performed by utilizing the fact that the open terminal voltage of the battery 3 has a high correlation with the charge amount SOC. The terminal voltage V of the battery 3 when the current I is 0 is measured to estimate the state of charge SOC2. Then, the charge amount SOC1 calculated by integrating the charge / discharge current I is corrected by the charge amount SOC2 estimated from the terminal voltage V, and an accurate charge amount SOC is obtained. The terminal voltage V when the charge / discharge current I is 0 is measured by adjusting the generated power so that the generated power of the generator 2 is the same as the power consumption of the traveling motor 6. I is forcibly set to 0, and in that state the terminal voltage V
Is measured. Since the terminal voltage V of the measurement result can be regarded as an open terminal voltage, the charge amount SOC2 is estimated from the terminal voltage V. As a result, the charge / discharge current I is integrated and the charge amount SO
Compared with the conventional method of calculating C, it is possible to eliminate the detection error and the sampling error of the charging / discharging current I, and it is possible to obtain an accurate charge amount SOC every moment during traveling.

FIG. 2 is a flowchart showing a process for calculating the state of charge SOC1. The vehicle controller 8 executes this calculation process at every predetermined sampling time T1. In step 1, the current sensor 10 detects the charge / discharge current I of the battery 3. Next step 2
The sampling time T1 is added to the detected charging / discharging current I.
To the current-time product (I) during the sampling time T1.
* T1) is obtained. In step 3, the current-time product (I * T1) at the current sampling time is added to the charge amount SOC1 up to the previous sampling time to update the charge amount SOC1.

FIG. 3 is a flowchart showing the calculation of the charge amount SOC2 and the charge amount correction processing. The vehicle controller 8 executes this processing at every predetermined correction cycle T2 (<T1). In step 11, the vehicle speed Vs is detected by the vehicle speed sensor 11. In the following step 12, the running resistance P corresponding to the detected vehicle speed Vs is looked up from a map of the running resistance P with respect to the vehicle speed Vs measured in advance as shown in FIG. Running motor 5
Since the power consumption is almost the power for driving the vehicle overcoming the running resistance, if the power for the running resistance is generated by the generator 2, the supply of the running power from the battery 3 to the motor 5 becomes unnecessary. The charging / discharging current I becomes 0. Since the response of the engine-driven generator 2 is slow, a discharging current I flows from the battery 3 to the motor 5 when the vehicle is accelerating, and a charging current I flows from the motor 5 to the battery 3 during decelerating regeneration. Since constant-speed running and deceleration are repeated, there is ample opportunity for the charging / discharging current I to become zero. In step 13, the running resistance estimated value P
The power generation amount W is determined according to.

An example has been described in which the running resistance is estimated from the vehicle speed, the power for overcoming the running resistance and driving the vehicle is used as the power consumption of the motor, and the generated power is determined according to the estimated running resistance. Alternatively, the power consumption may be obtained by detecting the voltage and current of the motor 5.

In step 14, the power generation amount W is set to the upper limit value WL.
Is checked, and if it exceeds the upper limit value WL, the routine proceeds to step 15, where the power generation amount W is limited to the upper limit value WL. In step 16, the charging / discharging current I is detected by the current sensor 10, and in subsequent step 17, it is confirmed whether the charging / discharging current I is zero. When the absolute value of the charge / discharge current I is actually equal to or less than a predetermined value near 0, it is considered that the charge / discharge current I = 0. If the charge / discharge current I is not 0, the process proceeds to step 18 to check whether the correction period T2 has elapsed. If the correction period T2 has elapsed, the current charge amount correction processing is terminated. If the correction period T2 has not elapsed, the process returns to step 16, and the charge / discharge current I is detected again.

If the charging / discharging current I = 0 is detected within the correction period T2, the process waits at step 19 for a predetermined time td. In general, the terminal voltage of the battery at the moment when the charge / discharge current decreases to 0 does not indicate an accurate open voltage due to a physical delay inside the battery. Therefore, as shown in FIG. 5, the terminal voltage V1 at the time when a predetermined delay time td has elapsed from the moment when the charge / discharge current I decreases to 0 is detected as the open circuit voltage of the battery. This delay time td
Is set longer as the rate of decrease of the charge / discharge current I is higher and the temperature of the battery is lower. Step 20 after elapse of delay time
Then, the terminal voltage V of the battery 3 is detected by the voltage sensor 9 and is set as an open voltage.

In step 21, a charge amount SOC corresponding to the open-circuit voltage detection value V is looked up from a map of the charge amount SOC with respect to the previously measured open-circuit voltage, and the charge amount SOC2 is calculated.
Is estimated. In the following step 22, the charge amount SOC1 calculated by integrating the charge / discharge current I is corrected by the charge amount SOC2 estimated from the open circuit voltage V, and the final charge amount SOC is determined.

SOC = k * SOC1 + (1−k) * SOC2 In Equation 1, k is a correction coefficient, and 0 <k <1. The weights of the SOCs SOC1 and SOC2 can be changed by the correction coefficient k.

The correction coefficient k may be determined according to the average value of the charge / discharge current of the battery. Specifically, the correction coefficient k is increased as the average value of the charge / discharge current increases. When the charging / discharging current is large, it is considered that the degree of deviation of the terminal voltage from the accurate open-circuit voltage when the current = 0 is increased due to the internal resistance of the battery. Therefore, in such a case, the correction coefficient k is increased, and the weight of the charge amount SOC1 calculated by integrating the charge / discharge current I is increased. Further, the correction coefficient k may be changed according to the correction interval. When the charge / discharge current I = 0 is not detected for a long time and the correction interval is long, it is considered that the charge amount SOC1 calculated by integrating the charge current I includes many current detection errors and sampling errors. Can be Therefore, in order to remove such an error and obtain an accurate charge amount SOC, the correction coefficient k is reduced and the weight of the charge amount SOC2 estimated from the open circuit voltage V is increased. Alternatively,
The correction coefficient k may be determined by using the above method together.

FIG. 6 shows a correction cycle T according to this embodiment.
FIG. 2 is a diagram showing a timing of a charge / discharge current I = 0, and a correction timing (represented by a black circle). As shown in the figure, in this embodiment, the charge amount S is based on the terminal voltage V at the time when the charge / discharge current I first becomes 0 during the correction period T2.
OC2 is estimated, and the charge amount SOC1 calculated by integrating the charge / discharge current I with the charge amount SOC2 is corrected. That is, the predetermined correction cycle T2 is set, and the correction operation of the charge amount is executed only once in one cycle. As a result, the charge amount SOC of the battery 3 while the vehicle is running can be reduced without imposing a large burden on the microcomputer of the vehicle controller 8.
Can be accurately detected.

In step 23, the state of charge SOC is output to and displayed on the display unit 12, and is output to various in-vehicle devices as needed.

As described above, the charge amount of the battery is calculated by integrating the charge / discharge current detection value of the battery,
The current consumption of the motor is detected, and the power generated by the generator is controlled so that the amount of power generated by the generator matches the current consumption of the motor. Further, the terminal voltage of the battery when the charge / discharge current detection value becomes substantially zero is detected, and the amount of charge of the battery is estimated based on the battery voltage detection value. Since the calculated charge amount is corrected based on the estimated charge amount, the charge / discharge current can be integrated to remove the charge / discharge current detection error and sampling error from the calculated charge amount. The quantity can be determined. Also, since the battery terminal voltage is detected a predetermined time after the charging / discharging current detection value becomes substantially zero and is set as the open voltage, the delay of the voltage change with respect to the current change due to the physical properties inside the battery is compensated. It is possible to obtain an accurate open circuit voltage of the battery.

In the configuration of the above embodiment, the engine 1 is the engine, the generator 2 is the generator, the battery 3 is the battery, the motor 6 is the motor, the current sensor 10 is the battery current detecting means, and the vehicle The controller 8 constitutes a charge amount calculating means, a power consumption detecting means, a power generation control means and a charge amount correcting means, the vehicle controller 8 and the voltage sensor 9 constitute a battery voltage detecting means, and the vehicle speed sensor 11 constitutes a vehicle speed detecting means.

In the above-described embodiment, a series hybrid vehicle has been described as an example. However, the present invention can be applied to a series parallel hybrid vehicle (SPHV) and other types of hybrid vehicles. it can.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment.

FIG. 2 is a flowchart showing a charge amount calculation process based on integration of a charge / discharge current.

FIG. 3 is a flowchart illustrating a charge amount estimation process based on an open circuit voltage and a charge amount correction process.

FIG. 4 is a diagram showing a map of running resistance P with respect to vehicle speed Vs.

FIG. 5 is a diagram showing the timing of charging / discharging current I = 0 and the timing of detecting the open-circuit voltage V;

FIG. 6 is a diagram showing a charge amount correction cycle, a charge / discharge current I = 0 timing, and a charge amount correction timing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Generator 3 Battery 4 Generator controller 5 Motor controller 6 Motor 8 Vehicle controller 9 Voltage sensor 10 Current sensor 11 Vehicle speed sensor 12 Indicator

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H02J 7/00 H02J 7/00 J 7/10 7/10 H (72) Inventor Hiroyuki Hirano 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd. (72) Inventor Eiji Inada Kanagawa Prefecture, Yokohama City, Kanagawa Ward, Takaracho 2 (Nissan Motor Co., Ltd.) Inventor Yutaro Kaneko Nissan Motor Co., Ltd., 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa

Claims (10)

[Claims] 1. A hybrid vehicle battery comprising: a generator driven by an engine; a chargeable / dischargeable battery; and a traveling motor driven by the power generated by the generator and / or the power discharged by the battery. In the charge amount calculation device, a battery current detection unit that detects a charge / discharge current of the battery; a charge amount calculation unit that integrates a charge / discharge current detection value of the battery to calculate a charge amount of the battery; Power consumption detection means for detecting power consumption; power generation control means for controlling the power generated by the generator to match the power consumption detection value of the motor; and the charging / discharging current during control by the power generation control means. Battery voltage detecting means for detecting a terminal voltage of the battery when the detected value becomes substantially zero; A hybrid vehicle comprising: a charge amount estimating unit that estimates a charge amount of the battery based on a Lee voltage detection value; and a charge amount correction unit that corrects the charge amount calculation value by the charge amount estimation value. Battery charge calculator. 2. The battery charge calculating device for a hybrid vehicle according to claim 1, wherein the power consumption detecting means has a vehicle speed detecting means for detecting a vehicle speed, and estimates a running resistance according to the detected vehicle speed value. A battery charge calculating device for a hybrid vehicle, wherein the power consumption of the motor is detected in accordance with the estimated running resistance. 3. The apparatus according to claim 1, wherein the power consumption detecting means detects a motor voltage detecting means for detecting a terminal voltage of the motor, and detects a current flowing through the motor. A device for calculating the amount of charge in a battery of a hybrid vehicle, comprising: motor current detection means; and detecting power consumption based on the motor voltage detection value and the motor current detection value. 4. The battery charge calculating device for a hybrid vehicle according to claim 1, wherein the battery voltage detecting means determines a predetermined time from when the charge / discharge current detection value becomes substantially zero. A battery charge calculation device for a hybrid vehicle, wherein a terminal voltage of the battery after a lapse of time is detected. 5. The hybrid vehicle battery charge calculating device according to claim 4, wherein the predetermined time is made longer as the rate of decrease of the charge / discharge current detection value is higher. Arithmetic unit. 6. The battery charge amount calculating device for a hybrid vehicle according to claim 4, further comprising a battery temperature detecting means for detecting a temperature of the battery, wherein the predetermined time is set longer as the detected battery temperature value is lower. A battery charge calculation device for a hybrid vehicle, comprising: 7. The battery charge calculating device for a hybrid vehicle according to claim 1, wherein the charge correcting means weights the calculated charge and the estimated charge. And a battery charge calculating device for the hybrid vehicle, wherein the final charge is determined. 8. The battery charge amount calculating device for a hybrid vehicle according to claim 7, wherein the charge amount correction unit increases the weight of the charge amount calculation value as the average value of the charge / discharge current detection values increases. A battery charge calculation device for a hybrid vehicle, characterized in that: 9. The battery charge calculating device for a hybrid vehicle according to claim 7 or 8, wherein the charge amount correcting means determines a time interval from a previous charge amount correction time to a current charge amount correction time. A battery charge amount calculating device for a hybrid vehicle, wherein the weight of the charge amount estimation value is increased as the length is longer. 10. The device for calculating the amount of charge in a battery of a hybrid vehicle according to claim 1, wherein the charge amount correcting means sets a predetermined cycle, and performs the charge only once in one cycle. A battery charge calculation device for a hybrid vehicle, which performs a charge correction operation.