JPH11227439A - Fan motor drive and control vevice for vehicle air conditioning system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve merits, lacked in analogue control, such as simple circuit constitution, reduced power consumption, and the difficulty in occurrence of a circuit oscillation by digital control, and also the suppression of output fluctuation due to input noise, and the stabilization of output to ignition voltage fluctuation without complicated circuit constitution and a liable circuit oscillation. SOLUTION: A PWM output port 5a is provided on a CPU 5 incorporated in an air conditioning control unit 1, and a fan motor drive and control circuit is adopted as a PWM module 2 for directly driving and controlling a fan motor 3 by a PWM signal from the unit 1. The CPU 5 is provided with an IGN data filter treating part 53 for filter-treating an ignition voltage AD value ADIGN to adopt it as an ignition voltage data IGNDATA, and an ignition correction treating part 51 for correcting a PWN duty ratio operation value VF0 to adopt it as a PWM duty ratio IGN correction value VF1 so that both the end voltage of the motor 3 is not changed even ignition voltage IGN is fluctuated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a fan motor drive control device of a vehicle air conditioning system for controlling the drive of a fan motor for obtaining a target air volume determined by an air conditioning control unit.

[0002]

2. Description of the Related Art Conventionally, as a fan motor drive control device of a vehicle air conditioning system, for example, an analog drive type device as shown in FIG. 7 is known.

The fan motor drive control in the apparatus shown in FIG. 7 is performed by a CPU built in an air conditioning control unit.
The PWM output is converted to D /
A conversion is performed, and the fan motor is driven by analog control directly from the air conditioning control unit.

[0004]

However, the above-mentioned conventional fan motor drive control device for a vehicle air-conditioning system has the following problems since it uses an analog drive system.

(1) Since the circuit configuration including the ignition correction circuit is complicated, the cost is high and the man-hour is required for the design.

(2) MOS is consuming unnecessary energy because of analog control. That is, as long as the motor is in a movable state, a drain current always flows through the MOS, and this current portion is lost, power consumption increases,
Heat generation is also increased.

(3) Since a closed circuit having feedback extends over the air-conditioning control unit and the fan motor drive control circuit, it is difficult to take measures against fan drive noise due to circuit oscillation. That is, in order to prevent circuit oscillation, the capacitors and diodes in the circuit must be tuned for each vehicle type or each vehicle.

In order to solve the problem of the analog drive system, the present applicant has proposed a fan motor drive control for a vehicle air-conditioning system described in Japanese Patent Application Laid-Open Nos. Hei 7-276968 and Hei 7-300011. The device was proposed.

This apparatus uses a PWM (Pulse Width Modula).
Option: Pulse width modulation) Drive control method is adopted.
When PWM control is applied to the input of the power transistor,
It can be replaced with switch ON / OFF control,
This has the effect of significantly reducing power consumption. In addition, the circuit configuration can be simplified as compared with the analog circuit, and the problem of circuit oscillation is reduced.

However, with respect to the ignition correction even in a device of the PWM drive control system, when the ignition correction circuit as shown in FIG. 7 is employed, the problem of the above (1) that the circuit configuration becomes complicated, and the circuit oscillation As a result, the problem of the above (3) that measures for driving noise of the fan are difficult is left.

The problem to be solved by the present invention is that digital control achieves the advantages of analog control that the circuit configuration is simple, power consumption is reduced, and circuit oscillation is unlikely to occur. It is an object of the present invention to provide a fan motor drive control device of a vehicle air-conditioning system that suppresses output fluctuations due to input noise and stabilizes output with respect to ignition voltage fluctuations without complicating or making circuit oscillation easy to occur. is there.

[0012]

(Means for Solving the Problems) A means for solving the above problems (Claim 1) is an air conditioning control unit based on input information from a fan switch, a sensor or the like, and a set air volume control program. In a fan motor drive control device of a vehicle air conditioning system that drives a fan motor by outputting a control command to obtain a determined target air flow to a fan motor drive control circuit, CPU
A PWM output port for obtaining a PWM output obtained by modulating a pulse width output in a constant cycle in accordance with a target air volume; providing a fan motor drive control circuit having a MOS transistor; a fan motor based on a PWM signal from an air conditioning control unit; A PWM module in which the motor is directly driven and controlled,
The CPU includes an ignition data filter processing unit configured to filter an ignition voltage detection value to generate ignition voltage data by filtering the ignition voltage detection value, and to filter the ignition voltage data filtered so that the voltage across the fan motor does not change even when the ignition voltage fluctuates. Based on P
An ignition correction processing means for correcting the WM duty ratio calculation value is provided.

[0013] (Solution 2) In the fan motor drive control apparatus for a vehicle air-conditioning system according to claim 1, the ignition data filter processing means sets a small filter constant. The input value input from the ignition voltage input circuit to the ignition voltage input port of the CPU is filtered by program software to generate ignition voltage data.

[0014]

(Embodiment 1) Embodiment 1 is a fan motor drive control device for a vehicle air-conditioning system according to the first and second aspects of the present invention.

First, the configuration will be described.

FIG. 1 is an overall system diagram showing a fan motor drive control device of the vehicle air conditioning system according to the first embodiment.

In FIG. 1, 1 is an air conditioning control unit, 2 is a PWM module (fan motor drive control circuit), 3 is a fan motor, 4 is a harness, 5 is a CPU,
6 is a waveform amplification circuit, 7 is a surge protection circuit, 8 is a cut O
FF circuit, 9 is a voltage divider circuit, 10 is a surge protection circuit, 11
Is a temperature fuse, 12 is a drive circuit, 13 is a MOS transistor, 14 is a filter circuit, 15 is an output gate, 16
Is an input gate, 17 and 18 are motor terminal gates, 19 is an ignition power supply gate, and 20 is an earth gate.

[Configuration of Air-Conditioning Control Unit] In the air-conditioning control unit 1, a target air volume is determined based on input information from a fan switch and a sensor (not shown) and a set air volume control program. A PWM signal (control command) for obtaining the air volume is output to the PWM module 2 via the harness 4.

The CPU 5 is built in the air-conditioning control unit 1 and has a frequency higher than the audible range (18 k).
PWM that modulates a pulse width output at a constant frequency of, for example, 20 kHz) at a frequency equal to or higher than Hz.
A PWM output port 5a for obtaining an output, a cut-off output port 5b for obtaining a cut-off output, and an AD input port 5c for obtaining an AD input of an ignition voltage are provided. The CPU 5 includes an ignition correction processing unit 51 that sets the PWM duty ratio calculation value VFO to the PWM duty ratio IGN correction value VF1 so that the voltage across the fan motor 3 does not change even if the ignition voltage IGN changes.
(Ignition correction processing means) and a PWM characteristic correction processing unit which sets a PWM duty ratio IGN correction value VF1 to a PWM duty ratio characteristic correction value VF2 so that the motor drive voltage changes in proportion to the PWM duty ratio, and uses this as a PWM output. 52, and an IGN data filter processing unit 53 (ignition data filter processing means) for filtering the ignition voltage AD value ADIGN to obtain ignition voltage data IGNDATA used in the ignition correction processing are incorporated as program software.

Between the PWM output port 5a of the CPU 5 and the output gate 15, an open collector circuit composed of a transistor TR1 is provided, and a waveform amplifying circuit 6 for amplifying the PWM output waveform is provided by diodes D1, D2 and a capacitor C1. A surge protection circuit 7 is provided.

The cut-off output port 5 of the CPU 5
A cut-off circuit 8 including a transistor TR2, a resistor R2, and a capacitor C2 is provided between b and the base side of the transistor TR1.

The AD input port 5c of the CPU 5
Ignition voltage VIGN (8 to 15.4V)
A voltage dividing circuit 9 including resistors R3 and R4 for dividing the voltage to 5V, and a surge protection circuit 1 including a diode D3 and a capacitor C3.
0 is connected. The voltage dividing circuit 9 and the surge protection circuit 10 correspond to an ignition voltage input circuit in the claims.

[Regarding Configuration of PWM Module] The PWM module 2 includes a temperature fuse 11 and a driving circuit 1.
2, a MOS transistor 23, and a filter circuit 14. A PWM signal from the air conditioning control unit 1 is input via the harness 4, and the fan motor 3
It is driven directly by the M signal.

The drive circuit 12 is provided with a waveform shaping transistor TR3 for shaping the signal waveform blunted by the harness 4 at the preceding stage of the MOS transistor 13, and the space between the air conditioning control unit 1 and the PWM module 2 is low. Bias resistors R6, R7, R8 are provided so as to be driven by the voltage (6V). Note that the resistors R5 and R
9 is a bias resistor for MOS drive.

The MOS transistor 13 applies a voltage to the gate based on the PWM signal from the air-conditioning control unit 1, and changes the width of a path (channel) of electrons from the source to the drain by the gate voltage.
Controls drain current. D4 is a surge killer diode.

The filter circuit 14 includes the fan motor 3
And the coil L1 to stabilize the driving voltage of the fan motor 3.

In FIG. 1, IGN is a battery ignition voltage of 9 to 16 V, and VIGN is 8 to 16 V.
It is the ignition voltage which passed through the diode of the reverse connection protection of 15.4V, and VDD is the air-conditioning control unit power supply of 4.5-5.2V.

Next, the operation will be described.

[Regarding PWM Drive] PWM (pulse width modulation) drive means a duty cycle of a pulse width to be output at a constant period (Hi of pulse width) according to an input command value.
gh and Low).

That is, when the sawtooth wave and the signal wave of the input command value are directly added, the pulse width of the PWM as viewed in the voltage waveform becomes the width at which the sawtooth wave and the signal wave intersect, as shown in FIG. It is proportional to the magnitude of the signal wave.

Here, the input command value includes, as input information, a sensor signal from a fan switch, a suction temperature sensor, or the like for switching the air volume between first speed, second speed, and third speed by manual operation, and a mixed door opening signal. This is a value for obtaining a predetermined target air volume when an optimal target air volume is determined for an input condition by a preset air volume control program.

[Power Consumption] Comparing the power consumption of the PWM drive system and the conventional analog drive system,
In the case of the M drive system, when PWM control is applied to the input of the power transistor, it can be replaced with ON / OFF control of a switch. On the other hand, in the case of the analog drive system,
Control other than when the motor is stopped can be replaced with control in which the switch is always ON.

Therefore, as shown in FIG. 3, the PWM driving method has an effect of significantly reducing power consumption as compared with the analog driving method. For example, if the voltage between the motor terminals is 7V
In this case, the power consumption is 10 W or less in the PWM driving method, while the power consumption is 60 W in the analog driving method.
W, which is a significant difference in power consumption of about 50 W.

[Regarding the Fan Motor Drive Control Operation] In the drive control of the fan motor 3, the PWM output port 5 a of the CPU 5 built in the air conditioning control unit 1 is used.
, A PWM output is output at a constant cycle at a frequency (20 kHz) higher than the audible range, and this PWM output is amplified by the waveform amplifier circuit 6 to become a PWM signal, passes through the surge protection circuit 7, and passes from the output gate 15 to the harness 4. Sent to The PWM signal from the harness 4 is converted into a gate voltage to be applied to the gate of the MOS transistor 13 in the drive circuit 12, and the drain voltage of the MOS transistor 13 is controlled by the gate voltage.
Are driven by the voltage between the motor terminals according to the duty ratio of the PWM signal.

Here, in the preceding stage of the MOS transistor 13 of the PWM module 2, a waveform shaping transistor TR for shaping the PWM output waveform sent from the harness 4 is provided.
3 is provided, the signal waveform distorted in the harness 4 is returned to an orderly form like the PWM signal waveform in the air conditioning control unit 1, and the MOS transistor 13
A gate voltage having a prescribed voltage level can be applied to the gate of the gate.

The bias resistances R6, R7 and R8 are provided in the PWM module 1 so that the air conditioning control unit 1
The harness 4 connecting the power supply and the PWM module 2 is driven at a low voltage of 5 V, so that the PWM output is set to a high frequency of 20 kHz, so that its harmonics enter the radio frequency range and cause radio noise. Can be prevented from occurring.

Further, electrolytic capacitors C4 to C12 inserted at both ends of the fan motor 3 are connected to the PWM module 2.
Since the filter circuit 14 including the coil L1 and the filter circuit 14 is provided, the drive voltage of the fan motor 3 can be stabilized by a filter function that suppresses the fluctuation of the voltage between the terminals of the fan motor 3.

[Regarding Fan Motor Drive Control Operation] FIG. 4 is a flowchart showing the flow of the fan motor drive control operation executed by the CPU 5, and each step will be described below.

At step 60, it is determined whether or not the ignition switch has been turned from OFF to ON.
When the determination is NO, the process proceeds to step 62, and when the determination is NO, the process proceeds to step 61.

At step 61, the air conditioning system is turned off.
It is determined whether or not the answer is YES.
The process proceeds to step 63 when NO is determined.

In step 62, it is determined whether or not the control system is performing a self-diagnosis. When the determination is YES, the process proceeds to step 72, and when the determination is NO, the process proceeds to step 63.

In step 63, when the control start condition is satisfied, PWM data calculation processing is performed. In this PWM data calculation processing, a PWM duty ratio calculation value VFO for obtaining an optimum target air flow for an input condition is obtained by an air flow control program.

In step 64, it is determined whether or not the PWM duty ratio calculation value VFO obtained in step 63 is equal to or more than the upper limit value. If YES, the duty ratio MAX value (100%) is set in step 65 as the calculation value VFO. You.

In step 66, it is determined whether or not the PWM duty ratio calculated value VFO obtained in step 63 is equal to or lower than the lower limit. If YES, the duty ratio MIN value (0%) is set in step 67 as the calculated value VFO. You.

In step 68, the ignition voltage I
An ignition correction process is performed to correct the PWM duty ratio calculation value VFO (PWM duty ratio IGN correction value VF1) so that the voltage across the fan motor 3 does not change even if GN fluctuates (in the range of about 9V to about 16V). You.

In step 69, a PWM characteristic correction process is performed in which the PWM duty ratio IGN correction value VF1 is changed to the PWM duty ratio characteristic correction value VF2 so that the motor drive voltage changes in proportion to the PWM duty ratio.

In step 70, it is determined whether the output to the fan motor 3 is ON or OFF. When the fan output is normal, the process of turning on the fan output is performed in step 71, such as when the low water temperature is started. When the fan output is OFF, the processing at the time of fan output OFF is performed in step 72.

In step 73, the ignition voltage A
Ignition voltage data IGNDATA used in the ignition correction process by filtering the D value ADIGN
IGN data filter processing is performed.

[IGN Data Filtering Process] The IGN data filtering process executed in step 73 will be described with reference to the flowchart shown in FIG.

At step 90, it is determined whether or not the ignition switch has been turned from OFF to ON.
When the determination is NO, the process proceeds to step 91, and when the determination is NO, the process proceeds to step 92.

In step 91, the ignition voltage A at the time when the ignition switch is turned from OFF to ON is set.
D value ADIGN is the initial ignition voltage data IGNDATA
Is set as

In step 92, the magnitude relationship between the input ignition voltage AD value ADIGN and the ignition voltage data IGNDATA which is a memory value is compared.

In step 93, when ADIGN> IGNDATA, data increment is performed such that IGNDATA + 1 → IGNDATA.

In step 94, when ADIGN <IGNDATA, the data is decremented so that IGNDATA-1 → IGNDATA.

Incidentally, the AD value of 0 V to 5 V is 0 bit to 2 bits.
55-bit IGNDATA corresponds, and in one filter processing cycle, the change of 1-bit IGNDATA is suppressed. When ADIGN = IGNDATA, the ignition voltage data IGNDATA is not increased or decreased.

As described above, while reducing the filter constant so that the voltage dividing circuit 9 and the surge protection circuit 10, which are the ignition voltage input circuits, are small in size, the ignition voltage AD value ADIGN is filtered to obtain the ignition voltage. By executing the IGN data filter processing using the data IGNDATA, output fluctuation (chattering) due to input noise is suppressed.

[Ignition Correction Processing] The ignition correction processing executed in step 68 will be described with reference to FIG.

IGNDATA is the filtered ignition voltage data, KIGN is the ignition reference voltage, VFO
Is the PWM duty ratio calculation value, the PWM duty ratio IGN correction value VF1 is obtained by the following equation.

VF1 = (KIGN / IGNDATA) * VFO For example, as shown in FIG. 6A, when IGNDATA is 16V,
When KIGN is 12 V and VFO is 40%, VF1 is 30% according to the above equation. That is, when the ignition voltage is higher than the reference voltage, the fan motor 3 is driven at a value lower than the PWM duty ratio calculation value VFO by the duty ratio due to the voltage difference.

As shown in FIG. 6B, when IGNDATA is 10V, KIGN is 12V, and VFO is 40%, VF1 is 48% according to the above equation. That is, when the ignition voltage is lower than the reference voltage, the fan motor 3 is driven at a value higher than the PWM duty ratio calculation value VFO by the duty ratio due to the voltage difference.

As described above, while monitoring the ignition voltage IGN, the PWM duty ratio calculation value VFO is changed to the PWM duty ratio IGN with respect to the ignition reference voltage KIGN.
By correcting to the correction value VF1, the ignition voltage IG
Stabilization of the output to the fan motor 3 with respect to the fluctuation of N is achieved. Further, since the ignition correction process is performed by the program software incorporated in the CPU 5, the circuit configuration can be complicated as in the case of an ignition correction circuit having a conventional hardware configuration. It does not make it easy to happen.

Next, the effects will be described.

The fan motor drive control device of the vehicle air conditioning system according to the first embodiment can achieve the following effects together.

(1) Since it is a digital circuit, the circuit configuration on the air conditioning control unit 1 side is simplified, and the design is easier than that of a conventional analog circuit.

(2) Since digital control is performed by the PWM drive system, power consumption is significantly reduced as compared with the analog drive system. In other words, energy is saved, heat generation of the MOS transistor 13 is reduced, and the heat sink, which is a heat sink, is reduced in size, the MOS transistor 13 is reduced in size, and the cost of the device is reduced.

(3) Air conditioning control unit 1 and PWM
Module 2 is a single harness 4 that sends a PWM signal.
Only, and a closed circuit is not formed between the first and second circuits. Therefore, oscillation of the circuit hardly occurs, and tuning of the circuit is facilitated.

(4) Since the PWM output from the PWM output port 5a is a pulse width modulated output at a frequency of 20 kHz higher than the audible frequency range, the M that operates on / off is operated.
The switching sound of the OS transistor 13 is not heard outside the audible range.

(5) The ignition voltage AD is supplied to the CPU 5.
Filter the value ADIGN to the ignition voltage data
An IGN data filter processing unit 53 that sets IGNDATA and an ignition that corrects the PWM duty ratio calculation value VF0 to set the PWM duty ratio IGN correction value VF1 so that the voltage across the fan motor 3 does not change even if the ignition voltage IGN changes. Since the correction processing unit 51 is provided, it is possible to suppress output fluctuations due to input noise and to stabilize the output against fluctuations in the ignition voltage IGN without complicating the circuit configuration and making the circuit oscillation more likely to occur.

(6) The ignition data filter processing unit 53 filters the ignition voltage AD value ADIGN input to the AD input port 5c of the CPU 5 from the voltage dividing circuit 9 and the surge protection circuit 10 in which the filter constant is set small by the program software. Since the processed voltage is used as ignition voltage data IGNDATA, the voltage dividing circuit 9 and the surge protection circuit 10 can be reduced in size.

[0070]

According to the first aspect of the present invention, a target air volume is determined by an air conditioning control unit based on input information from a fan switch, a sensor, or the like, and a set air volume control program. In a fan motor drive control device of a vehicle air-conditioning system that drives a fan motor by outputting a control command for obtaining an air volume to a fan motor drive control circuit, a pulse width output at a constant cycle to a CPU built in an air conditioning control unit. A PWM output port for obtaining a PWM output obtained by modulating a PWM according to a target airflow, a fan motor drive control circuit having a MOS transistor, and a PWM module in which a fan motor is directly driven and controlled by a PWM signal from an air conditioning control unit. The CPU performs a filtering process on the ignition voltage detection value to perform ignition processing. Ignition data filtering means for generating ignition voltage data, and an ignition correction process for correcting a PWM duty ratio calculation value based on the filtered ignition voltage data so that the voltage across the fan motor does not change even if the ignition voltage fluctuates. Because of the provision of the means, the digital control achieves the advantages of analog control that the circuit configuration is simple, the power consumption is reduced and the circuit oscillation is unlikely to occur, and the circuit configuration is complicated. It is possible to provide a fan motor drive control device for a vehicle air-conditioning system that suppresses output fluctuations due to input noise and stabilizes the output with respect to fluctuations in ignition voltage without making it easy to occur.

In the invention according to claim 2, claim 1
In the fan motor drive control device for a vehicle air-conditioning system described above, the ignition data filter processing means performs a filter processing by a program software on an input value input from an ignition voltage input circuit having a small filter constant to an ignition voltage input port of the CPU. Since the ignition voltage data is used as the means for generating the ignition voltage data, the ignition voltage input circuit can be reduced in size in addition to the effect of the first aspect.

[Brief description of the drawings]

FIG. 1 is an overall system diagram showing a fan motor drive control device of a vehicle air conditioning system according to a first embodiment.

FIG. 2 is a diagram showing how to generate a voltage waveform of a PWM signal of a fan motor drive control device of the vehicle air conditioning system according to the first embodiment.

FIG. 3 is a comparison characteristic diagram of power consumption between a PWM drive system and a conventional analog drive system by a fan motor drive control device of the vehicle air conditioning system according to the first embodiment.

FIG. 4 is a flowchart showing a flow of a fan motor drive control operation executed by a CPU of an air conditioning control unit of the device according to the first embodiment.

FIG. 5 is a flowchart showing a flow of an ignition data filtering operation executed by a CPU of an air conditioning control unit of the device according to the first embodiment.

FIG. 6 is an explanatory diagram of an ignition correction processing operation executed by a CPU of an air conditioning control unit of the device according to the first embodiment.

FIG. 7 is an overall system diagram showing a fan motor drive control device of a conventional vehicle air conditioning system using an analog drive system.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Air-conditioning control unit 2 PWM module (fan motor drive control circuit) 3 Fan motor 4 Harness 5 CPU 51 Ignition correction processing part (Ignition correction processing means) 52 PWM characteristic correction processing part 53 IGN data filter processing part 6 Waveform amplification circuit 7 Surge Protection circuit 8 Cut-off circuit 9 Voltage divider circuit 10 Surge protection circuit 11 Thermal fuse 12 Drive circuit 13 MOS transistor 14 Filter circuit 15 Output gate 16 Input gate 17, 18 Motor terminal gate 19 Ignition power supply gate 20 Earth gate TR3 Waveform shaping transistor R6, R7, R8 Bias resistor C4-C12 Electrolytic capacitor

Claims (2)

[Claims] An air conditioning control unit (1) determines a target air flow based on input information from a fan switch, a sensor, and the like, and a set air flow control program, and issues a control command to obtain the determined target air flow to a fan motor. In a fan motor drive control device of a vehicle air conditioning system that outputs to a drive control circuit to drive a fan motor (3), the C motor included in the air conditioning control unit (1)
A PWM output port for obtaining a PWM output in which a pulse width output at a constant cycle is modulated to a PU (5) in accordance with a target air volume.
(5a), wherein the fan motor drive control circuit is a MOS transistor
(13) and the PW from the air conditioning control unit (1)
PWM in which fan motor (3) is directly driven and controlled by M signal
An ignition data filter processing means (53) for filtering an ignition voltage detection value to generate ignition voltage data by the CPU (5) as a module (2), and a fan motor (3) even when the ignition voltage fluctuates. A fan motor drive control device for a vehicle air conditioning system, comprising: an ignition correction processing means (51) for correcting a PWM duty ratio calculation value based on ignition voltage data filtered so as not to change the voltage between both ends. 2. The fan motor drive control device for a vehicle air conditioning system according to claim 1, wherein said ignition data filter processing means (53) is provided from an ignition voltage input circuit (9), (10) having a small filter constant. A fan motor drive control device for a vehicle air conditioning system, characterized in that the input value input to an ignition voltage input port (5c) of the CPU (5) is filtered by program software to generate ignition voltage data.