JP5482576B2 - Inductive load drive control device and drive control method - Google Patents

Description

  The present invention relates to an inductive load drive control device and an inductive load drive control method, and is particularly suitable for application to a drive control device and a drive control method for an inductive load such as a solenoid actuator used in an automatic transmission for automobiles. Is.

In a solenoid actuator used in an automatic transmission for automobiles, there is a method of controlling a current flowing through an inductive load by PWM (pulse width modulation) control.
In such an inductive load control, in order to reduce the sliding resistance of the inductive load, an inductive load drive control device that superimposes current ripple waveform control information as a dither signal on a PWM signal to be current controlled, and A drive control method has been proposed (see, for example, Patent Document 1).

  Control current output means for changing the control current of the solenoid in a step-like manner according to the change of the control condition and outputting, dither current output means for outputting the dither current whose level is inverted at a predetermined cycle, and dither current for the control current Control current change for controlling the dither current to change in the same direction as the control current change direction at the same time as the control current change direction. A solenoid control device provided with timing control means has been proposed (see, for example, Patent Document 2).

By the way, as shown in FIG. 13, when the signal waveform is a triangular wave signal, the dither current forms a peak and a valley at 8 times the PWM cycle Tp and becomes one cycle with respect to the target current value. When Td is set, the shape of the dither control target current value waveform varies depending on the change timing of the target current value.
That is, as shown in FIG. 14A, when the target current value greatly increases between the time point t1 and the time point t2 delayed from the time point t1 by the PWM period Tp, the point of the dither signal at the time point t1 From P7, the point shifts to the point P0 of the dither signal at time t2, and the dither signal is superimposed on the target current value after the change from the start time of the dither cycle Td.

As shown in FIG. 14B, when the target current value greatly increases between the time point t2 and the time point t3 delayed from the time point t2 by the PWM cycle Tp, the dither signal point P0 at the time point t2 is obtained. 14 to the point P1 of the dither signal at time t3, and the dither signal is superimposed on the target current value after the change from the point toward the valley of the dither cycle. As shown in (d), when the change point of the target current value is further delayed, the target current value after the change starts from the point P2 at the bottom of the dither cycle or starts from the subsequent point P3. It will be.

JP 2009-176940 A JP-A-5-45046

  However, in the conventional examples described in Patent Documents 1 and 2, as shown in FIGS. 14A to 14D, the start point of the dither signal differs depending on the change point of the target current value. become. For this reason, when high-speed stability related to transient response characteristics is required in an automatic transmission or the like, the timing at which the cycle of the dither signal and the target current value (set value current information) are updated is not related to the dither signal cycle. Due to the periodicity, the waveform of the dither signal is constant in the PWM cycle after the change in the target current value due to the difference in the phase state of the dither control target current signal and the timing at which the control target current value increases or decreases (current control information change timing) It will not be. As a result, there is an unresolved problem of causing characteristic deterioration such as an increase in response time of the control current value, an increase in overshoot amount, and an increase in undershoot amount.

Further, there is an unsolved problem that radio noise increases as described in Patent Document 2 depending on operating conditions.
Therefore, the present invention has been made paying attention to the unsolved problems of the above-described conventional example, and an inductive load drive control device and an induction capable of aligning the start positions of the dither control target current values after the target current value is changed. An object of the present invention is to provide a sexual load drive control method.

In order to solve the above-described problem, an inductive load drive control device according to one aspect of the present invention performs drive control of the inductive load by PWM control so that the current flowing through the inductive load approaches a target current value. and control means, the set current value, a target value control means for generating said target current value by adding the current control value of the predetermined amplitude having has a significant period than the period of the PWM control, the set current value Current control amount addition control means for starting addition of the current control amount from a specific phase state of the current control amount when there is a change , and the current control amount addition control means includes a plurality of cycles of the current control amount. A feature is that the phase state is selected from a plurality of divided phases .

An inductive load drive control device according to another embodiment of the present invention is characterized in that the current control amount has a current waveform of one of a triangular wave and a sine wave .

An inductive load drive control device according to another aspect of the present invention is configured to change a specific phase state of the current control amount selected by the current control amount addition control unit according to a change direction of the set current value. It is characterized by doing.
Further, the inductive load drive control device according to another aspect of the present invention is such that when the current control amount addition control means has a change amount of the set current value equal to or larger than a predetermined value, the change direction of the set current value The specific phase state of the current control amount to be selected in accordance with is changed.

An inductive load drive control device according to another aspect of the present invention provides a phase state in which the current control amount addition control means is a valley of the current control amount when the set current amount changes in an increasing direction. And when the set current amount changes in a decreasing direction, the phase state that is the peak of the current control amount is selected.
The inductive load drive control method according to one aspect of the present invention includes a step of performing drive control of the inductive load by PWM control so that a current flowing through the inductive load approaches a target current value;
The set current value, and generating the target current value by adding the current control value of the predetermined amplitude having has a significant period than the period of the PWM control, the current control amount during the change of the set current value Adding a specific phase state from a plurality of divided phases obtained by dividing one period of the current control amount into a plurality of phases, and starting from the specific phase state of the selected current control amount. It is said.

According to the present invention, a current control amount having a predetermined amplitude having a period larger than the period of PWM control is added to control the fluctuation period of the target current value, thereby minimizing the sliding resistance of the linear solenoid. The amount of current ripple can be given by the target current value.
When the set current value changes, the addition of the current control amount to the set current value can be started from a specific phase state of the current control amount, so the convergence time to the target current value is shortened and overshoot The response characteristic can be improved by reducing the current and the undershoot current, and the change width of the target current value can be suppressed within a certain range, and the radio noise can be reduced.

1 is a block diagram showing a schematic configuration of a closed loop control system to which an inductive load drive control device according to a first embodiment of the present invention is applied. FIG. 2 is a block diagram illustrating a schematic configuration of a drive control circuit in FIG. 1. FIG. 2 is an equivalent circuit diagram showing a schematic configuration of the closed loop control system of FIG. 1. 2 is a timing chart for explaining the operation of the drive control circuit in FIG. 1. It is a figure which shows the relationship between the current ripple frequency and the sliding resistance of a linear solenoid. It is a block diagram which shows the specific structure of the target value control part of FIG. It is a figure which shows an example of the target electric current value waveform output from the target value control part. It is a flowchart which shows an example of the control information generation process procedure performed in the phase control information generation part at the time of a target change of FIG. It is a flowchart which shows an example of the target electric current value production | generation processing procedure performed with the signal generation circuit of FIG. It is a figure which shows an example of the target electric current value waveform at the time of the change of the increase direction of setting electric current value information. It is a figure which shows the other example of the target electric current value waveform at the time of the change of the increase direction of setting electric current value information. It is a figure which shows an example of the target electric current value waveform at the time of the decreasing direction change of setting electric current value information. It is a figure which shows the target current value waveform of a prior art example. It is a figure which shows the target current value waveform of the prior art example at the time of target current value increase.

Hereinafter, an inductive load drive control device according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of a closed loop control system to which an inductive load drive control device according to an embodiment of the present invention is applied.
In FIG. 1, a drive circuit 13 is connected to one end of an inductive load 15 such as a solenoid actuator used for an automatic transmission, for example, and the other end of the inductive load 15 is grounded via a current detection resistor 17. . A drive control circuit 12 that performs PWM control by analog processing is connected to the previous stage of the drive circuit 13, and a target value control unit 11 is connected to the previous stage of the drive control circuit 12.

An average current detection circuit 14 is connected to both ends of the current detection resistor 17, and an output side of the average current detection circuit 14 is connected to the drive control circuit 12.
Here, the drive control circuit 12 performs drive control of the inductive load 15 so that the current If flowing through the inductive load 15 is varied by PWM control so as to approach (follow) the target current value I ^* . For example, the drive control circuit 12 sets the pulse width by PWM control based on the deviation between the average value I _{AVR of the} current If flowing through the inductive load 15 and the target current value I ^* .

The target value control unit 11 controls the fluctuation cycle (dither cycle) Td of the target current value I ^* so as to be larger than the control cycle Tp by the PWM control of the current If flowing through the inductive load 15. For example, the fluctuation cycle Td of the target current value I ^* is set so that the sliding resistance of the linear solenoid that is the inductive load 15 is minimized, and the control cycle Tp by PWM control follows the target current value I ^* . Thus, the current ripple amount of the changing current If is set so as to match the current detectable range by the average current detection circuit 14. That is, the smaller the control period Tp by PWM control, the smaller the fluctuation of the current If by PWM control. Therefore, even if the amplitude of the target current value I ^* is large to some extent, the control period Tp is reduced to reduce the peak current I _{H of the} current If. In addition, the bottom current I _L is set within the current detectable range.

Then, the set current value information FI specifying the average value I _AVR of the current If flowing through the inductive load 15 is input to the target value control unit 11. Then, the target value control unit 11 generates a target current value I ^* having a fluctuation cycle Td larger than the control cycle Tp by PWM control and having the average value I _AVR specified by the set current value information FI, and driving Input to the control circuit 12.
The current If flowing through the inductance L of the inductive load 15 flows through the current detection resistor 17, and the average value I _{AVR of the} current If flowing through the inductive load 15 is detected by the average current detection circuit 14, and is supplied to the drive control circuit 12. Entered.

Then, the drive control circuit 12 generates a PWM signal so that the current If flowing through the inductive load 15 follows the target current value I ^*, and performs on / off control of the switching element of the drive circuit 13, thereby inductive. The current If flowing through the load 15 is PWM controlled.
As a result, the current If flowing through the inductive load 15 can be controlled to follow the fluctuation period Td of the target current value I ^* that is larger than the control period Tp by PWM control, and the sliding resistance of the linear solenoid is minimized. Current ripple frequency can be given by the target current value I ^* .

  For this reason, it becomes possible to reduce the control cycle Tp of the current by the PWM control flowing through the inductive load 15, and even when the characteristics of the inductive load 15 are different, the PWM control influenced by the characteristics of the inductive load 15 Since the increase / decrease in the amount of current ripple can be reduced, the current ripple can be adjusted on the same circuit so as to match the detectable range of the current If flowing through the inductive load 15 while reducing the sliding resistance of the linear solenoid. It is possible to change with.

FIG. 2 is a block diagram showing a schematic configuration of the drive control circuit 12 of FIG.
In FIG. 2, the drive control circuit 12 is provided with a triangular wave oscillator 21, a D / A converter 22, an operational amplifier 23 having a differential amplifier configuration, and a comparator 24, and the drive circuit 13 is provided with a field effect transistor 25. .
The output terminal of the D / A converter 22 is connected to one input terminal of the operational amplifier 23, the output terminal of the average current detection circuit 14 is connected to the other input terminal of the operational amplifier 23, and one input of the comparator 24 is connected. The output terminal of the triangular wave oscillator 21 is connected to the terminal, the output terminal of the operational amplifier 23 is connected to the other input terminal of the comparator 24, and the output terminal of the comparator 24 is connected to the gate of the field effect transistor 25.

An inductance L of the inductive load 15 is connected in series to the field effect transistor 25, and a cathode of a diode Di is connected to a connection point between the field effect transistor 25 and the inductance L.
The target current value I ^* generated by the target value control unit 11 is converted into analog data by the D / A converter 22 and then input to the operational amplifier 23 and detected by the average current detection circuit 14. The average value I _{AVR of the} current If flowing through the inductance L of the inductive load 15 is also input to the operational amplifier 23. The operational amplifier 23 detects a deviation between the target current value I ^* and the average value I _AVR of the current If and then inputs the deviation to the comparator 24. Further, the triangular wave generated by the triangular wave oscillator 21 is input to the comparator 24, and the deviation between the target current value I ^* and the average value I _AVR of the current If is compared with the triangular wave generated by the triangular wave oscillator 21. .

When the deviation between the target current value I ^* and the average value I _AVR of the current If is greater than the level of the triangular wave generated by the triangular wave oscillator 21, an on signal is sent from the comparator 24 to the gate of the field effect transistor 25. When the difference between the target current value I ^* and the average value I _AVR of the current If is less than or equal to the level of the triangular wave generated by the triangular wave oscillator 21, an off signal is output to the comparator 24 at the gate of the field effect transistor 25. Is output from.

The field effect transistor 25 is turned on when an on signal is input to the gate, and the current If flowing through the inductance L increases. On the other hand, the field effect transistor 25 is turned off when an off signal is input to the gate, and the current If flowing through the inductance L decreases, whereby the current If flowing through the inductive load 15 is PWM-controlled, and the inductive load 15 Is controlled such that the current If flowing in the current follows the target current value I ^* . The diode Di is a commutation diode for providing a current path for the current If when the field effect transistor 25 is turned off.

FIG. 3 is an equivalent circuit diagram showing a schematic configuration of the closed loop control system of FIG.
In FIG. 3, the field effect transistor 25 can be equivalently expressed by the switching element SW and the on-resistance R _ON , and the inductive load 15 can be equivalently expressed by the inductance L and the solenoid resistance R _L. .
A power source Vbat, a switching element SW, an ON resistance R _ON , a solenoid resistance _RL, and an inductance L are sequentially connected in series.

Next, the operation of the closed loop control system of FIG. 1 will be described based on the timing chart shown in FIG. For simplification of explanation, the figure assumes that the dither signal is ignored.
Now, it is assumed that the set current value information FI input to the target value control unit 11 increases step by step as shown in FIG.
As the set current value information FI increases, the target current value I ^* output from the target value control unit 11 increases, and the pulse width of the voltage waveform of the PWM control signal output from the drive control circuit 12 according to this increase. Increases as shown in FIG.

  That is, when the set current value information FI changes between the time point t1 in FIG. 4 and the time point t2 after the PWM control cycle Tp, the pulse width of the PWM control signal at the time point t2 when the next control cycle Tp starts. Will increase. Similarly, when the set current value information FI increases between the time points t4 and t5, the pulse width of the PWM control signal increases at the time point t5, and when the set current value information FI decreases between the time points t7 and t8, the PWM at the time t8. The pulse width of the control signal is reduced.

Then, the current If flowing through the inductance L of the inductive load 15 according to the pulse width of the PWM control signal increases as shown in FIG. 4C when the PWM signal is at a high level, and the PWM signal is at a low level. Sometimes decreases.
Since the detection result of the average current of the current If flowing through the inductance L is reflected in the control cycle Tp of the next PWM control signal as shown in FIG. 4D, the average detected by the average current detection circuit 14 The current value increases at time t3 and then increases at time t6. In this case, the average current detection circuit 14 receives an A / D converter to which the voltage across the current detection resistor 17 is input, an arithmetic circuit for obtaining an average current from the output of the A / D converter, and an output of the arithmetic circuit. The circuit includes a D / A converter and is synchronized with the triangular wave oscillator 21 and calculates and outputs an average current for each control period Tp of PWM control. However, the present invention is not limited to this configuration.

Here, for simplicity, it is assumed there is no on-resistance R _ON and the solenoid resistance R _L of FIG. 3, the voltage of the power supply Vbat V _BAT, a period when the switching element SW is turned on in the control period Tp of the PWM control Assuming T _R and the off-period are T _F , the following formulas (1) to (3) are obtained for the peak current I _H , the bottom current I _L, and the average value I _AVR of the current If. .
I _H −I _L = V _BAT / L · T _R = V _F / L · T _F (1)
Tp = T _R + T _F (2)
I _AVR = (I _H + I _L ) / 2 (3)
Here, V _F is the forward voltage of the diode Di. When these equations (1) to (3) are solved, the following relationships (4) to (6) are obtained.
I _H = I _AVR + V _BAT · V _F · Tp / (2L · (V _BAT + V _F )) (4)
I _L = I _AVR -V _BAT · V _F · Tp / (2L · (V _BAT + V _F )) (5)
T _R = V _F · Tp / (V _BAT + V _F ) (6)

As shown in the equations (4) and (5), it can be seen that the current ripple amount (I _H −I _L ) is inversely proportional to the value of the inductance L and proportional to the control cycle Tp. For this reason, by increasing the frequency of the PWM signal and reducing the control period Tp, the amount of current ripple (I _H −I _L ) by PWM control can be reduced. Even if the average value I _AVR changes, even if the characteristics of the inductive load 15 are different by reducing the control cycle Tp, the change of the average value I _AVR and the PWM are within the current detectable range of the average current detection circuit 14. The amount of current ripple (I _H −I _L ) combined with the variation due to control can be accommodated.

FIG. 5 is a diagram showing the relationship between the current ripple frequency and the sliding resistance of the linear solenoid. If the control period Tp of the PWM signal is reduced in the state of FIG. 4 and the frequency of the PWM signal is set to f1 shown in FIG. 5, the linear solenoid slide resistance is away from the frequency f2 at which the linear solenoid slide resistance is minimized. Dynamic resistance increases.
For this reason, the fluctuation cycle Td of the target current value I ^* given to the drive control circuit 12 is made larger than the control cycle Tp of the PWM signal, and the frequency of the target current value I ^* is set to f2, thereby controlling the PWM signal. Even when the period Tp is reduced, the sliding resistance of the linear solenoid can be minimized, so that the sliding resistance of the linear solenoid can be reduced while conforming to the detectable range of the current If flowing through the inductive load 15. It is possible to change the current ripple on the same circuit.

On the other hand, as shown in FIG. 6, the specific configuration of the target value control unit 11 includes a cycle / time information (time information is information for a non-sinusoidal wave) of the target current value I ^* as a fixed value. Time information holding unit 31, current ripple information holding unit 32 holding current ripple information of target current value I ^* as a fixed value, set current value information holding unit 33 holding set current value information FI as a variable, target current value I ^* timing generating circuit 34 and a signal generating circuit 35 for generating a target current value I ^* of the waveform to produce a generation timing of setting the phase states at the start of dither control to be described later when the set current value information FI is changed A dither control start phase setting register 36 and a target change time phase control information generation unit 37 are provided.

Here, the current ripple information of the target current value I ^* held by the current ripple information holding unit 32 is not limited to (I _H −I _L ), but may be the peak current I _H and the bottom current I _L. There is also an I _RIPPLE described later. Here, I _H and I _L are obtained by narrowing the upper and lower limits of the current detectable range by the maximum value of the fluctuation range of the current If by PWM control. The same applies hereinafter.

When the set current value information FI is input to the target value control unit 11, the set current value information FI is held in the set current value information holding unit 33. The timing generation circuit 34 generates the generation timing of the target current value I ^* based on the period / time information held in the period / time information holding unit 31 and outputs the generation timing to the signal generation circuit 35. Then, the signal generation circuit 35 follows the generation timing generated by the timing generation circuit 34 and sets the current ripple information held in the current ripple information holding unit 32 and the setting current value information holding unit 33. Based on the current value information FI and the contents of the dither control start phase setting register 36, a waveform of the target current value I ^* is generated and output to the drive control circuit 12 of FIG.

Here, as shown in FIG. 7, the target value control unit 11 in FIG. 1 generates a triangular waveform of the target current value I ^* in which the average value I _AVR is specified by the set current value information FI. The waveform of the target current value I ^{* is} a waveform of a dither control target current value obtained by adding a triangular-wave-shaped control current having a predetermined amplitude to the set current value information FI, and includes eight points P0 to P7 for each PWM cycle. One period is formed, a valley region is formed at points P0 to P4, and a mountain region is formed at points P4 to P0. Then, the target current value I ^* is divided by a quarter period, a point P2 in the quarter period, a point P2 in the half period, a point P4 in the third quarter period, and a point in the first period P0 is set as the start phase when the set current value information FI changes. These start phases are set in the dither control start phase setting register 36 as shown in Table 1 below by 2-bit “1” and “0”.

The dither control start phase setting register 36 receives target change phase control information for setting the start phase when the set current value information FI changes from the target change phase control information generation unit 37, and this target change. Based on the time phase control information, the start phase of the control current amount when the set current value information FI changes is input to the signal generation circuit 35.
The target change phase control information generating unit 37 receives the set current value information FI held in the set current value information holding unit 33, and based on the change of the set current value information FI, the target change phase control is performed. Generate time information. That is, the target change phase control information generation unit 37 is configured to include an arithmetic processing unit such as a microcomputer, and executes the control information generation process shown in FIG. 8 based on the set current value information FI.

This control information generation process is executed as a timer interrupt process for each predetermined time (for example, the control period Tp of PWM control). First, in step S1, the current set current held in the set current value information holding unit 33 Read the value information FI (n), then move to step S2, and subtract the previously read set current value information FI (n-1) from the read current set current value information FI (n). A current value change amount ΔFI is calculated.
Next, the process proceeds to step S3, where it is determined whether or not the absolute value of the set current value change amount ΔFI calculated in step S2 is greater than or equal to a preset set value ΔFIs. If | ΔFI | <ΔFIs. It is determined that the set current value change amount ΔFI is small or “0”, and it is not necessary to set the dither control start phase, and the timer interrupt process is terminated as it is, and the process returns to the predetermined main program.

On the other hand, when the determination result in step S3 is | ΔFI | ≧ ΔFIs, it is determined that the set current value change amount ΔFI is large and an event to be taken into account in generating the target current value I ^* has occurred, and the process proceeds to step S4. Then, it is determined whether or not the set current value change amount ΔFI is positive. This determination is to determine whether the set current value information FI has changed in an increasing direction or a decreasing direction. When ΔFI> 0, it is determined that the set current value information FI has changed in an increasing direction. Then, the process proceeds to step S5.

In this step S5, it is determined whether or not the set current value change amount ΔFI is greater than or equal to the set value ΔFIs1 larger than the set value ΔFIs. If ΔFI <ΔFIs1, the process proceeds to step S6, where the dither control start phase setting register is set. The target change phase control information of “00” is output to 36, and then the timer interrupt process is terminated and the process returns to the predetermined main program.
If the determination result in step S5 is ΔFI ≧ ΔFIs1, the process proceeds to step S7, and the target interrupt phase control information “01” is output to the dither control start phase setting register 36, and then the timer interrupts. The process ends and the process returns to a predetermined main program.

If the determination result in step S4 is ΔFI <0, it is determined that the set current value information FI has changed in the decreasing direction, and the process proceeds to step S8. In step S8, it is determined whether or not the absolute value of the set current value change amount ΔFI is greater than or equal to a set value ΔFIs1 larger than the set value ΔFIs. If | ΔFI | <ΔFIs1, the process proceeds to step S9, and the dither is performed. After the target change phase control information of “10” is output to the control start phase setting register 36, the timer interrupt process is terminated and the process returns to a predetermined main program.
On the other hand, if the determination result in step S8 is | ΔFI | ≧ ΔFIs1, the process proceeds to step S10, and the target change time phase control information of “11” is output to the dither control start phase setting register 36 before the timer. Ends the interrupt process and returns to the predetermined main program.

  The signal generation circuit 35 includes an arithmetic processing unit such as a microcomputer, and executes a target current value generation process shown in FIG. This target current value generation process is executed as an interrupt process synchronized with the control cycle Tp of the PWM control signal described above. First, in step S11, the current set current value held in the set current value information holding unit 33. The information FI (n) is read, and then the process proceeds to step S12, and the set current value information FI (n-1) read last time is subtracted from the read current set current value information FI (n). After calculating the value change amount ΔFI, the process proceeds to step S13.

In this step S13, it is determined whether or not the absolute value of the set current value change amount ΔFI calculated in step S12 is greater than or equal to a preset set value ΔFIs. If | ΔFI | <ΔFIs, the process proceeds to step S14. Then, based on the current ripple information held in the current ripple information holding unit 32 and the timing signal input from the timing generation circuit 34, the current ripple information read point is sequentially incremented from the point P0 to the point P7. When it reaches, the process returns to the point P0 repeatedly to determine the dither control current amount DI as the control current amount, and then proceeds to step S15.
In step S15, the dither control current amount DI set in step S14 is added to the set current value information FI to calculate a dither control target current value I ^* that becomes a target current value, and this is output to the drive control circuit 12. After that, the interrupt process is terminated and the process returns to a predetermined main program.

If the determination result in step S14 is | ΔFI | ≧ ΔFIs, the process proceeds to step S16 to read the set value of the dither control start phase setting register 36, and then the process proceeds to step S17 to hold the current ripple information. From the current ripple information held in the unit 32, the phase ripple corresponding to the set value of the dither control start phase setting register 36, that is, the current ripple information at the point Pi (i = 0, 2, 4, 6) is read start dither control current. After determining the amount DI, the process proceeds to step S15.
In addition, the processing timing of the microcomputer is adjusted so that the processing in step S16 is always after the processing in steps S6 to S10.
It should be noted that the current control amount load control means is configured by the processing of steps S14 to S17 of the target value generation processing executed by the dither control start phase setting register 36, the target change phase control information generation unit 37, and the signal generation circuit 35 described above. ing.

Next, the operation of the above embodiment will be described.
As the entire operation of the closed loop system of FIG. 1, the PWM control is performed according to the target current value I ^* generated based on the value of the set current value information FI, as in the case of the time chart shown in FIG. The pulse width of the signal is controlled, and the current waveform flowing through the inductance L of the inductive load 15 changes as shown in FIG. 4C, and the average current flowing through the inductance L is changed accordingly as shown in FIG. In the same manner as in (), control is performed so as to follow the target current value I ^* .
At this time, even if the set current value information FI input to the target value control unit 11 does not change or has changed, if the absolute value of the change amount ΔFI is less than the set value ΔFIs, the target change phase control information generation unit At 37, new target change phase control information is not output to the dither control start phase setting register 36.

On the other hand, the signal generation circuit 35 executes the target current value generation process of FIG. 9, and even if there is no change or no change in the set current value information FI, the absolute value of the change ΔFI is less than the set value ΔFIs. Therefore, the process proceeds from step S13 to step S14, and the current ripple information corresponding to the point P (i + 1) incremented by incrementing the point Pi is read and determined as the dither control current amount DI (step S14). ), The dither control current amount DI is added to the set current value information FI to calculate the dither control target current value I ^*, and the calculated dither control target current value I ^* is output to the drive control circuit 12. The dither control target current value I ^{* at} this time has a triangular wave shape that rises and falls across the set current value information FI as indicated by the characteristic line L1 in FIG.

From the state in which the set current value information FI does not change or the absolute value of the change amount ΔFI is less than the set value ΔFIs, the set current value information FI increases from 200 mA to 300 mA, for example, between time points t1 and t2 in FIG. When the set current value change amount ΔFI = 100 mA and the increase amount is greater than or equal to the set value ΔFIs and less than the set value ΔFIs1, the target change phase control information generation unit 37 performs the control information generation process shown in FIG. When executed, the process proceeds from step S3 to step S4, and since the set current value change amount ΔFI is positive, the process proceeds to step S5, and since the set current value change amount ΔFI is less than the set value ΔFIs1, the process proceeds to step S6. Transition.
Therefore, “00” is stored in the dither control start phase setting register 36 for the target conversion phase control information of “00”.

  On the other hand, in the signal generation circuit 35, since the target current generation process shown in FIG. 9 is executed, the set current value change amount ΔFI is equal to or larger than the set value ΔFIs. Therefore, the process proceeds from step S13 to step S16, and the dither control starts. The setting value of the phase setting register 36 is read, and then the current lip information at the point corresponding to the setting value of the register 36 is set as the reading start dither control current amount DI.

At this time, since “00” is stored in the dither control start phase setting register 36, as shown in FIGS. 10A to 10D, the set current value information FI regardless of the change time of the set current value information FI. At the time after the change, the point P0 of the first period of the current ripple information is read out. Therefore, the start phase of the current ripple information does not vary when the set current value information FI changes as shown in FIG. 14 in the conventional example described above, and the amount of change in the dither control target current value can be suppressed. it can. For this reason, the convergence time to the target current value when the set current value information FI changes can be shortened, the overshoot current and the undershoot current can be reduced, and the response characteristics can be improved. . Moreover, since the change width of the target current value I ^* can be suppressed within a certain range, radio noise can be reduced.

  Further, when the set current value information FI changes from 300 mA to 500 mA, for example, between time points t4 and t5 in FIG. 4 and the set current value change amount ΔFI reaches 200 mA and becomes equal to or greater than the set value ΔFIs1, the phase control during target change is performed. When the information generation unit 37 executes the control information generation process of FIG. 8, the process proceeds from step S3 to step S4 to step S5. Since ΔFI ≧ ΔFIs1, the process proceeds to step S7. In this step S 7, the target change phase control information “01” is output to the dither control start phase setting register 36.

For this reason, when the target current value generation process of FIG. 9 is executed by the signal generation circuit 35, the process proceeds from step S13 to step S16 in the same manner as described above, so that the dither control start phase setting register 36 is set. The current ripple information at the valley bottom point P2 corresponding to the set value “01” is determined as the read start dither control current amount DI, and the read start dither control current amount DI is set as the set current value. A dither control target current value I ^* is calculated by adding to the information FI and is output to the drive control circuit 12.

Therefore, the dither control target current value I ^* is, as shown in FIGS. 11A to 11D, at a time after the set current value information FI changes regardless of the change time of the set current value information FI. A point P2 at the bottom of the quarter cycle of the current ripple information is read out. Accordingly, the start phase of the current ripple information when the set current value information FI changes as shown in FIG. 14 in the above-described conventional example does not vary, and the change amount of the dither control target current value is suppressed to the minimum value. can do. For this reason, the convergence time to the target current value when the set current value information FI changes can be shortened, the overshoot current and the undershoot current can be reduced, and the response characteristics can be improved. . In addition, since the change width of the target current value I ^* can be suppressed within a certain range, radio noise can be reliably reduced.

  Further, when the set current value information FI suddenly decreases from, for example, 500 mA to 100 mA between time points t7 and t8 in FIG. 4, the control information generation process in FIG. 8 is executed by the target change phase control information generation unit 37. As a result, the absolute value of the set current value change amount ΔFI becomes equal to or greater than the set value ΔFIs and equal to or greater than the set value ΔFIs1, and the set current value change amount ΔFI becomes a negative value. The process proceeds to step S 10, where the target change phase control information of “11” is output to the dither control start phase setting register 36, and the setting value “11” is stored in this register 36.

For this reason, when the target current value generation process of FIG. 9 is executed by the signal generation circuit 35, as shown in FIGS. 12A to 12D, the point P6 that becomes the third quarter of the current ripple information Is determined as the read start dither control current amount DI, and the read start dither control current amount DI is added to the set current value information FI to calculate the dither control target current value I ^* represented by the characteristic line L3. The target current value I ^* is output to the drive control circuit 12.

Also in this case, as in FIGS. 10 and 11, the dither control target current value I ^* is equal to the set current regardless of the change point of the set current value information FI, as shown in FIGS. At the time after the value information FI changes, the peak P6 at the peak of the third quarter of the current ripple information is read out. Accordingly, the start phase of the current ripple information when the set current value information FI changes as shown in FIG. 14 in the above-described conventional example does not vary, and the change amount of the dither control target current value is suppressed to the minimum value. can do. For this reason, the convergence time to the target current value when the set current value information FI changes can be shortened, the overshoot current and the undershoot current can be reduced, and the response characteristics can be improved. . In addition, since the change width of the target current value I ^* can be suppressed within a certain range, radio noise can be reliably reduced.

  In the above embodiment, the current ripple information is divided into four to set four phase positions of 1/4 cycle, 1/2 cycle, 3/4 cycle, and 1 cycle, and the change direction of the set current value information FI However, the present invention is not limited to this. However, the current ripple information is divided into eight as shown in FIG. 7 and the direction and change of the set current value information F1. The phase start position can be finely set based on the amount and the point representing the phase of the current ripple information before the set current value information FI changes. Furthermore, the number of divisions of the current ripple information can be set to an arbitrary number by setting the control cycle Tp of PWM control to be shorter.

In the above embodiment, the case where the current ripple information is formed in a triangular wave shape has been described. However, the present invention is not limited to this, and the current ripple information may be formed in a sine wave shape.
Further, in the above embodiment, the target value control unit 11 is changed to the period / time information holding unit 31, the current ripple information holding unit 32, the set current value information holding unit 33, the timing generation circuit 34, the signal generation circuit 35, and the dither control start. Although the case where the phase setting register 36 and the target change phase control information generation unit 37 are configured has been described, the present invention is not limited to this, and the target value control unit 11 itself includes an arithmetic processing unit such as a microcomputer. Then, the process including the phase control information generation process shown in FIG. 8 and the target value generation process shown in FIG. 9 is executed to calculate the dither control target current value I ^* based on the set current value information FI. You may make it output to the drive control circuit 12. FIG.

  Moreover, in the said embodiment, although the case where the target change time phase control information generation part 37 was provided in the target value control part 11 was demonstrated, it is not limited to this, The target change time phase control information generation part 37 is formed outside the target value control unit 11, and the target change phase control information generated by the target change phase control information generation unit 37 is set in the dither control start phase setting register 36 in the target value control unit 11. You may do it.

In the above embodiment, the target value control unit 11 holds the waveform control information including the cycle / time information in the cycle / time information holding unit 31 and the current ripple information holding unit 32 holds the current ripple information in a fixed manner. However, the present invention is not limited to this. Waveform control information FR1 of the target current value I ^* is externally set in the period / time information holding unit 31, and the current ripple information is stored in the current ripple information holding unit 32. FR2 may be set from the outside.

DESCRIPTION OF SYMBOLS 11 ... Target value control part, 12 ... Drive control circuit, 13 ... Drive circuit, 14 ... Average current detection circuit, 15 ... Inductive load, 17 ... Current detection resistance, 21 ... Triangular wave oscillator, 22 ... D / A converter, 23 Operational amplifier, 24 Comparator, 25 Field effect transistor, Di Diode, L Inductance, R _L Solenoid resistance, R _ON On resistance, SW Switching element, Vbat Power supply, 31 Period / time information holding unit 32 ... Current ripple information holding unit, 33 ... Setting current value information holding unit, 34 ... Timing generation circuit, 35 ... Signal generation circuit, 36 ... Dither control start phase setting register, 37 ... Target control phase control information generation unit

Claims (6)

Drive control means for performing drive control of the inductive load by PWM control so that the current flowing through the inductive load approaches the target current value;
The set current value, a target value control means for generating said target current value by adding the current control value of the predetermined amplitude having has a significant period than the period of the PWM control,
Current control amount addition control means for starting addition of the current control amount from a specific phase state of the current control amount when the set current value changes ,
The inductive load drive control device, wherein the current control amount addition control means is configured to select a phase state from a plurality of divided phases obtained by dividing one period of the current control amount into a plurality .   The inductive load drive control device according to claim 1, wherein the current control amount has a current waveform of one of a triangular wave and a sine wave.   3. The inductive load drive according to claim 1, wherein the current control amount addition control unit changes a specific phase state of the current control amount selected according to a change direction of the set current value. Control device.   The current control amount addition control means changes a specific phase state of the current control amount selected according to a change direction of the set current value when the change amount of the set current value is equal to or greater than a predetermined value. The inductive load drive control device according to claim 1 or 2.   The current control amount addition control means selects a phase state that is a valley of the current control amount when the set current amount changes in the increasing direction, and when the set current amount changes in the decreasing direction, The inductive load drive control device according to claim 1, wherein a phase state that is a peak of the current control amount is selected.   Performing drive control of the inductive load by PWM control so that the current flowing through the inductive load approaches a target current value;
  Adding a current control amount with a predetermined amplitude having a period larger than the period of the PWM control to the set current value to generate the target current value;
  The addition of the current control amount when the set current value is changed, a specific phase state is selected from a plurality of divided phases obtained by dividing one period of the current control amount into a plurality, and a specific current control amount is selected. Starting from the phase state and
  An inductive load drive control method comprising:

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