JP2015074267A - Vehicular control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus enabling size and cost reduction of an element constituting reserve charging-means used for charging a capacitor, and prevention of deterioration in performance of controlling a load.SOLUTION: An apparatus performs: introducing a voltage of a battery detected by detection means (step S2) after an ignition key is turned on (Yes for step S1); reading charging time of a capacitor, the time corresponding to the detected voltage from memory (step S3); turning on a relay by a control part (step S5) when elapsed time, measured by a timer, from turning on of the ignition key exceeds the read charge time (Yes for step S4) to start power feed from the battery to a drive circuit; and supplying a power-steering motor with a given drive current, thus outputting assist torque.

Description

  In the present invention, a preliminary charging current is supplied to a capacitor provided between a load side of a relay for intermittently driving a drive current from an in-vehicle battery to a load and a ground by turning on an ignition key to perform a preliminary charging. The present invention relates to a vehicle control device that performs on-control.

  Conventionally, in an electric power steering device for a vehicle, when a driver performs a steering operation, a relay is turned on to supply a drive current to a motor from an in-vehicle battery such as a lead battery, and the motor is driven to generate auxiliary torque. Therefore, it is necessary to supply a large current from the battery as the drive current of the motor, and the value of the drive current is influenced by the operation of the motor and is not constant and includes a ripple component. Therefore, a relay is used to smooth out such a ripple. When a capacitor is provided between the load side and the ground and the ignition key is turned on, the precharging means supplies the precharging current to the capacitor to precharge the capacitor.

  At this time, since the capacitor has a large capacity, an inrush current may flow to the relay contact when the relay is turned on, and welding may occur. In order to prevent such relay contact welding, the capacitor pre-charging is completed. It has been proposed to turn on the relay after that (for example, Patent Document 1).

Republished patent WO99 / 17977 (see page 6, line 15 to page 7, line 17 and FIGS. 1 and 2)

  In the electric power steering apparatus described above, it is necessary to set the precharge current so that the difference between the voltage of the battery and the voltage of the capacitor does not always exceed a predetermined value based on the breakdown voltage of the relay and the capacitor is charged as soon as possible. On the other hand, in order to drive the motor as early as possible to improve the power steering control performance, set the capacitor pre-charging current to a large value, shorten the capacitor charging time as much as possible, and make the relay turn on early It is possible.

  At this time, considering that the voltage of a general vehicle battery is about 13 V (12.6 V to 12.8 V) in a normal use state and about 15 V when charging with an alternator, it is not constant and varies depending on the situation, as described above. In order to shorten the capacitor charging time as much as possible by setting the capacitor precharging current to a large value, the capacitor precharging current is set according to the maximum battery voltage and the charging time is controlled to a short constant value. It has been done conventionally.

  However, when the capacitor pre-charging current is set in accordance with the maximum battery voltage in this way, the current capacity of the electric power steering device increases due to the motor specifications, etc. A large pre-charging current is required to charge a large-capacity capacitor, and a large amount of high withstand voltage must be used as an element constituting the pre-charging means, resulting in an increase in cost. is there.

  On the other hand, if it is allowed to lengthen the charging time with emphasis on miniaturization and cost reduction of the elements constituting the preliminary charging means without considering the battery voltage being adjusted to the maximum state as described above, the capacitor It takes longer time to charge the battery to the required voltage, delays the timing to start driving the motor by turning on the relay, delays the start of output of auxiliary torque necessary for steering operation, and degrades the performance of power steering control I will invite you.

  An object of the present invention is to provide an apparatus that can reduce the size of an element that constitutes a precharging means for charging a capacitor, and that can prevent deterioration in load control performance at low cost.

  In order to achieve the above-described object, the vehicle control device of the present invention includes a relay for intermittently driving a drive current from an in-vehicle battery to a load, a capacitor provided between the load side of the relay and ground, Precharging means that operates by turning on an ignition key to supply a precharging current to the capacitor, and control means that controls the operation of the load by turning on the relay after precharging the capacitor by the precharging means The vehicle control device includes a detection unit that detects the voltage of the battery after the ignition key is turned on, and the control unit determines whether the detection voltage detected by the detection unit is high or low. The time from the start of precharging the capacitor by the precharging means until the relay is turned on is variably controlled. Section 1).

  According to the first aspect of the present invention, the control unit variably controls the time from the start of precharging the capacitor by the precharging unit to turning on the relay according to the level of the detected voltage of the battery detected by the detecting unit. Therefore, for example, when the detection voltage of the battery is low, the capacitor can be charged to the required voltage even in a short charging time, and the load control can be started by making the relay ON timing as early as possible. While the deterioration of control performance can be prevented, when the battery detection voltage is high, the capacitor can be charged to the required voltage by extending the charging time even if the capacitor precharge current is small. It is not necessary to make the elements constituting the means unnecessarily large with a high withstand voltage, and it becomes possible to use small and low-cost elements. .

It is a block diagram of the control device for vehicles concerning one embodiment of the present invention. It is operation | movement explanatory drawing of FIG. It is a flowchart for operation | movement description of FIG.

  Next, an embodiment in which the vehicle control device according to the present invention is applied to a control device for an electric power steering will be described in detail with reference to FIGS. 1 to 3. In the following description, electric power steering is referred to as EPS.

  As shown in FIG. 1, an EPS ECU (Electronic Control Unit) 2 comprising a microcomputer for controlling the operation of a power steering motor (hereinafter referred to as a power steering motor) 1 that outputs auxiliary torque to a steering (not shown) operated by a driver. The drive current from the in-vehicle battery 3 such as a lead battery is controlled by the EPS ECU 2.

  The EPS ECU 2 corresponds to the in-vehicle control device according to the present invention, and is configured as described below. That is, as shown in FIG. 1, the EPS ECU 2 includes a drive circuit 21 having an inverter configuration that outputs a drive current to a power steering motor 1 that is a load, and a relay 22 provided in the middle of a power supply line from the battery 2 to the drive circuit 21. And a ripple removing smoothing capacitor 23 provided between a terminal on the drive circuit 21 side of the relay 22 and the ground, and an ignition key (not shown) are turned on to operate a precharge current from the battery 3. A precharge circuit 24 serving as a precharge means to be supplied to the capacitor 23, and a voltage detection section for detecting the voltage at the input end of the precharge circuit 24 as the voltage Vb of the battery 3 after the ignition key is turned on (detection means in the present invention) And a relationship between the voltage Vb of the battery 3 and the charging time t of the capacitor 23 as a map in advance. The memory 26 and the voltage Vb of the battery 3 detected by the voltage detector 25 (hereinafter referred to as the detection voltage Vb) are read, the charging time corresponding to the detection voltage Vb is read from the memory 26, and the relay 22 is turned on. A control unit (corresponding to the control means in the present invention) 27 including a CPU for controlling timing, and a timer 28 for measuring the elapsed time from turning on the ignition key are provided.

  By the way, the voltage of the battery 3 is about 13V in the normal use state, and becomes a high voltage of about 15V when charged by the alternator. Therefore, as shown in FIG. Is lower than the voltage Vs (about 13 V) in the normal use state, the charging time t of the capacitor 23 becomes the constant time ta, and the detection voltage Vb of the battery 3 by the voltage detection unit 25 is the voltage in the normal use state. When the voltage is higher than Vs (about 13 V), the charging time t of the capacitor 23 is controlled to be long or short according to the level of the detection voltage Vb at that time.

  At this time, the relationship between the detection voltage Vb of the battery 3 and the charging time t of the capacitor 23 is obtained in advance by experiment or calculation, mapped, and stored in the memory 26 in advance. Specifically, in the case of calculation, assuming that the detection voltage Vb of the battery 3 is a voltage Vs (for example, 12 V) in a normal use state, if the required voltage Vc of the capacitor 23 at that time is 6 V, the detection voltage Vb A value obtained by dividing the difference between (12V) and the capacitor voltage Vc (6V) by a known circuit resistance is the precharge current of the capacitor 23. For example, if the circuit resistance is 1Ω, the precharge current is (12V-6V) / The time required for the precharge circuit 24 to supply the 6A precharge current to the capacitor 23 and the capacitor voltage Vc to 6V is stored in the memory 26 as the charge time ta.

  On the other hand, when the detection voltage Vb is higher than the voltage Vs in the normal use state (assumed to be 12 V for the sake of simplicity of calculation), the necessary voltage Vc of the capacitor 23 is also increased as a countermeasure for preventing the inrush current of the relay 22, In order to charge the capacitor 23 to the high voltage Vc with the same precharge current (6 A) as in the normal use state, the charge time may be increased, and the necessary capacitor voltage for each detection voltage Vb higher than the voltage Vs in the normal use state. Since Vc is known, if the time required for charging to the capacitor voltage Vc at that time is calculated by the precharge current (= 6 A) in the normal use state, the detection voltage Vb becomes the voltage Vs (12 V in the normal use state). ) Can be calculated, and the calculated charging time for the detected voltage at that time can be calculated. It may be stored in the re-26.

  After the ignition key is turned on, the charging time t of the capacitor 23 corresponding to the detection voltage Vb of the battery 3 by the voltage detection unit 25 is read from the memory 26 by the control unit 27 and is measured by the timer 28. When the elapsed time from the ON of the battery exceeds the read charging time t, the relay 22 is turned on by the control unit 27 and the power supply from the battery 3 to the drive circuit 21 is started, and the power steering motor 1 has a predetermined drive current. Is supplied and auxiliary torque is output.

  Next, the operation of the control unit 27 will be described with reference to the flowchart of FIG. Now, as shown in FIG. 3, it is determined whether there is an ignition key ON signal input (step S1). If this determination result is NO, the determination in step S1 is repeated until the determination result is YES. If the determination result is YES, that is, if the ignition key is turned on, the detection voltage Vb of the battery 3 by the voltage detection unit 25 is taken into the control unit 27 (step S2), and the detection voltage Vb from the memory 26 is received from the control unit 27. Is read out (step S3).

  Then, the control unit 27 determines whether or not the time measured by the timer 28 after the ignition key is turned on exceeds the charging time read from the memory 26 (step S4), and if this determination result is NO. This determination is repeated until the determination result is YES. If the determination result is YES, the contact of the relay 22 is turned on by the control unit 27 (step S5), and power supply from the battery 3 to the drive circuit 21 is started. A predetermined drive current is supplied to the power steering motor 1 to output an auxiliary torque, and the operation ends.

  Therefore, according to the above-described embodiment, after the ignition key is turned on, if the detection voltage Vb of the battery 3 detected by the voltage detection unit 25 is lower than the voltage Vs (about 13 V) in the normal use state, a certain charging time If the capacitor 23 is charged at ta and the detection voltage Vb of the battery 3 detected by the voltage detection unit 25 is higher than the voltage Vs (about 13 V) in the normal use state, the detected voltage is longer than the time ta. The capacitor 23 is charged with a charging time set to be long or short depending on the level of Vb.

  Therefore, when the detection voltage Vb is lower than the voltage Vs in the normal use state, the capacitor 23 can be charged to the necessary voltage even in a short charging time, and the control of the power steering motor 1 is started early by making the relay 22 turn on as early as possible. It is possible to prevent the power steering motor 1 from deteriorating the control performance of the power steering.

  On the other hand, when the detection voltage Vb is higher than the voltage Vs in the normal use state, the capacitor 23 can be charged to the required voltage by extending the charging time even if the precharge current of the capacitor 23 is small. It is not necessary to make the constituent elements unnecessarily large and have a high withstand voltage, and it is possible to use small and low-cost elements.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the case where the present invention is applied to the electric power steering control device (EPSECU2) has been described. The present invention can also be applied to a control device. In addition, the present invention can be similarly applied to a control device that supplies a current from a battery to a load by turning on a relay and includes a capacitor for ripple removal at that time. It is.

1 ... Power steering motor (load)
2 ... EPSECU (vehicle control device)
3 ... Battery 22 ... Relay 23 ... Capacitor 24 ... Precharge circuit (preliminary charging means)
25: Voltage detection unit 27: Control unit (control means)

Claims (1)

A relay for intermittently driving a drive current from an in-vehicle battery to a load, a capacitor provided between the load side of the relay and the ground, and a spare that operates by turning on an ignition key to supply a precharge current to the capacitor In a vehicle control device comprising: charging means; and control means for controlling the operation of the load by turning on the relay after preliminary charging of the capacitor by the preliminary charging means.
A detecting means for detecting the voltage of the battery after turning on the ignition key;
The control means variably controls the time from the start of preliminary charging of the capacitor by the preliminary charging means to turning on the relay according to the level of the detection voltage detected by the detection means. Control device.

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