JP2001289549A - Refrigerator control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and structure for controlling a refrigerator control device rendered noiseless and decreased in size and a cost and capable of performing PWM control or PWM/PAM control of a DC brushless motor. SOLUTION: A refrigerator control substrate is electrically separated into a power part circuit, consisting of a rectifying circuit and a compressor control part, and a control circuit part to perform control inherent to the refrigerator. Further, by causing each of the circuits to form different substrate structure, the refrigerator control device is provided to be small and improve noise resistance and have low-cost structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control circuit for a refrigerator which employs a DC brushless motor as a compressor and is driven by an inverter. In particular, the control circuit is divided into a power system and a control system. When a speed command is input, the number of revolutions of the motor can be automatically controlled by PWM control or PAM control, and the power unit can be arranged in a machine room of a refrigerator and the power supply circuit is provided in the power unit. Also, the present invention relates to a refrigerator control device capable of reducing the size of a circuit board for performing refrigerator-specific control and increasing the internal volume of the refrigerator, and a refrigerator using the same.

[0002]

2. Description of the Related Art Conventionally, a basic control circuit of a refrigerator that performs inverter control includes a rectifier circuit for converting AC to DC and a power factor improving circuit for suppressing harmonic current. There is generally one as described in FIG.

The circuit shown in FIG. 3 uses a voltage doubler rectifier circuit as a rectifier circuit, and a method of suppressing harmonic current is performed by an LC filter (passive filter) comprising a power factor improving reactor 84 and a capacitor 85. Filter) to suppress harmonic currents. Next, as a method of controlling the refrigerator, first, based on the temperature state of each of the sensors 74 to 77, the number of rotations of the DC brushless motor 50 for operating the compressor 51 corresponding to the situation by the macro computer 65, and the damper 58
, The state of the automatic ice making machine 59, the energized state of each heater 61-64, and the rotation speed of each fan motor 52-53 are calculated to determine what kind of operation the refrigerator should perform.

[0004] The microcomputer 65 outputs driving signals to a fan motor driver 55, a damper driver 56, a motor driver 57 for an automatic ice maker, and a heater driver 60. A signal via the V-phase and W-phase motor voltage detection resistors 43 to 48 and the DC brushless motor 5
Signals via the resistors 15 and 16 for detecting a value of 直流 of the DC voltage applied to 0 are respectively synthesized by the comparator 49 to create magnetic pole position information of the DC brushless motor 50 where the rotor is not described. After isolating the U-phase, V-phase, and W-phase rotor position information with an insulating element (such as a photocoupler), the rotor position detection method is performed by creating a filter circuit including a resistor, a capacitor, and a comparator. The same),
Based on this signal, a drive signal for driving the switching elements 18 to 23 for arbitrarily operating the DC brushless motor is created by calculation, and output to the switching elements 18 to 23 via the insulating elements 34 to 39 and the driver 30; P
The DC brushless motor 50 is operated at an arbitrary rotation speed by the WM control.

FIG. 4 uses a full-wave voltage rectifier circuit as a rectifier circuit, and a method for suppressing harmonic currents includes a booster reactor 6, a rectifier diode 7,
Active filter control is performed by the booster circuit 5 including the switching element 8 and the PAM control circuit 31. The control method of the refrigerator is similar to that of FIG.
7, the rotation speed of the DC brushless motor 50 for operating the compressor 51 corresponding to the situation by the macro computer 65, the opening degree of the damper 58, the state of the automatic ice maker 59, and the heaters 61 Calculate the energization states of the fan motors 64 to 64 and the rotation speeds of the fan motors 52 to 53 to determine what kind of operation the refrigerator should perform.

The microcomputer 65 outputs driving signals to a fan motor driver 55, a damper driver 56, a motor driver 57 for an automatic ice maker, and a heater driver 60. A signal via the V-phase and W-phase motor voltage detection resistors 43 to 48 and the DC brushless motor 5
Signals via the resistors 15 and 16 for detecting a value of 直流 of the DC voltage applied to 0 are respectively synthesized by the comparator 49 to create magnetic pole position information of the DC brushless motor 50 where the rotor is not described. After isolating the U-phase, V-phase, and W-phase rotor position information with an insulating element (such as a photocoupler), the rotor position detection method is performed by creating a filter circuit including a resistor, a capacitor, and a comparator. The same),
Based on this signal, a drive signal for driving the switching elements 18 to 23 for arbitrarily operating the DC brushless motor is created by calculation, and output to the switching elements 18 to 23 via the insulating elements 34 to 39 and the driver 30; P
The DC brushless motor 50 is operated at an arbitrary rotation speed by the WM control.

However, the rotation speed of the DC brushless motor 50 increases, and the chopper duty of the PWM control becomes 10
When it becomes 0%, the chopper is fixed at 100% without performing the chopper control of the switching elements 18 to 23,
The DC brushless motor 50 is a microcomputer 65
Microcomputer 5 so that the number of revolutions determined in
At 0, a DC voltage command signal for PAM control is calculated and created, and this DC voltage command signal is output from the microcomputer to the PAM control circuit 31 via the insulating element 32 so that the DC brushless motor 50 has an arbitrary rotation speed. Performs PAM control.

[0008]

However, as shown in FIG.
The refrigerator control device shown in FIG. 4 must perform a refrigerator-specific control such as fan motor control and damper control, automatic ice maker control, and DC brushless motor control for operating the compressor using a single microcomputer. Rather, control circuit components must be basically arranged on one circuit. In the case of a refrigerator, the installation place is often placed in a humid place such as a kitchen.
The power section of the brushless motor control circuit, to which high voltage is applied, and the refrigerator control section of the weak electric section, which can be easily touched by people such as SW and temperature control knob, must be insulated. In addition, a large number of insulating elements are used, the number of components increases, and a large board area is required. Further, since the substrate area is increased, the place where the substrate is installed is also limited, and the internal volume ratio of the refrigerator is also reduced.

In the refrigerator control device shown in FIGS. 3 and 4, since the power section and the wiring pattern of the circuit of the refrigerator control section are mixed on one board, the power section containing the high-frequency component is provided in the refrigerator control section. Therefore, sufficient noise countermeasures are required so that high-frequency noise is not affected.

[0010] Further, the refrigerator control device performs all controls by one microcomputer, so that, for example, when a part of the control program is changed, it may affect all the control programs. When it becomes necessary to change the microcomputer itself, all control programs must be programmed for the new microcomputer.

SUMMARY OF THE INVENTION An object of the present invention is to provide a refrigerator control apparatus which has a performance and a function required for a refrigerator, and which can be miniaturized in a mounting form, improved in noise resistance, and reduced in cost (reduced development period). Is provided.

[0012]

In order to achieve the above object, the present invention provides an inverter circuit comprising six semiconductor switching elements with control electrodes connected in a three-phase bridge.
A return diode reversely connected to the semiconductor switching element, a magnetic pole position detection circuit for detecting a magnetic pole position of a rotor of a DC brushless motor built in the compressor, a power factor correction switching element, a backflow prevention diode, and a control circuit therefor. , An LC normal filter circuit composed of a reactor and a capacitor, a common filter circuit composed of a capacitor and a choke coil, a rectifier circuit for converting AC power to DC, and a DC brushless motor built in the compressor at an arbitrary speed. A microcomputer A for controlling the inverter circuit and the power supply power factor improvement circuit for operation;
A power circuit including a power supply circuit for generating a power supply for the above circuit, a drive circuit for driving a fan motor, a drive circuit for driving a damper for controlling opening and closing of a cool air passage, and an automatic ice maker A drive circuit for driving the motor for driving the ice tray and a pump motor for supplying water to the ice tray, a heater drive circuit for energizing each heater in an energized state corresponding to each heater, and detecting the temperature of each part of the refrigerator The operation circuit of each fan motor, the energization state of each heater, the opening / closing angle of each damper, and the number of rotations of the compressor are calculated based on the input circuit of the temperature sensor and the information of each sensor.
An operation signal is output to each fan motor, each heater, and each damper to perform the operation of the operation result, and a rotation speed command signal of the operation result is output to the microcomputer A provided in the power circuit. And a control circuit constituted by a microcomputer B to be electrically separated.

The power section circuit and the control section circuit are electrically separated from each other, and if necessary, the circuit boards are separately formed so that each circuit board can be freely arranged. By doing so, each circuit board can be standardized.

Further, according to the present invention, the power unit circuit includes a microcomputer A and a non-volatile external storage element readable and writable a plurality of times by a pair with the microcomputer A, and this storage element is required to start and drive a DC brushless motor. By storing constants that need to be set for each type of motor, and changing these constants for each type of motor, the same circuit can be used without changing the circuit hardware even when the motor is changed. Is used.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. In the figure, the same reference numerals shown in the conventional example indicate the same items.

First, the symbols shown in FIG. 1 will be described.

FIG. 1 is a circuit block diagram showing one embodiment of a refrigerator control apparatus according to the present invention, wherein 1 is a commercial power supply, 2 is a common mode filter circuit, 3 is a normal mode filter circuit, 4 is a bridge diode for rectification, 5 is a booster circuit for PAM control, 6 is a choke coil of the booster circuit, 7 is a diode for preventing backflow of the booster circuit, 8 is a semiconductor switching element of the booster circuit, 9 is a smoothing capacitor, 10 and 11 are power supply voltage detection resistors, 12 Is the power supply current detection resistor, 13,1
4 is a DC voltage detection resistor, 15 and 16 are signal detection resistors for generating a rotor position detection signal of a DC brushless motor, 17 is a three-phase inverter circuit, 18, 19, 20, 21, 22, and 22.
23 is a semiconductor switching element forming an inverter bridge, 24, 25, 26, 27, 28 and 29 are freewheeling diodes forming an inverter bridge, 30 is a semiconductor switching element 18 forming an inverter bridge,
Drivers for driving 19, 20, 21, 22, 23;
1 is a power factor improvement control circuit, 32, 33, 34, 35, 3
6, 37, 38, 39, 40, 41, 42 are insulating elements (photocouplers), 43, 44, 45, 46, 47, 4
Reference numeral 8 denotes a motor terminal voltage detection resistor; 49, a comparator for generating a rotor magnetic pole position detection signal of a DC brushless motor;
Is a DC brushless motor, 51 is a compressor, 52, 53,
54 is a fan motor that circulates air in the refrigerator and the machine room, 55 is a driver that drives the fan motor, 56 is a driver that drives a damper that controls the opening of the refrigerator ventilation path, and 57 is an ice tray of an automatic ice machine. A driver for driving a rotating motor and a pump motor for supplying water to the ice tray, 58 is a damper installed in a ventilation path in the refrigerator (not shown), 59 is an automatic ice machine, and 60 is installed in each part of the refrigerator not shown. Drivers for energizing the heaters, 61, 62,
63 and 64 are heaters installed in each part of the refrigerator (not shown), 65 is a microcomputer, 66 is a control DC power supply circuit, 67 is a substrate, 68 is a DC voltage command generation transistor, 69 is a microcomputer, 70 is an insulating element, 71 is a substrate, 72 is a forced operation signal input terminal for operating the power unit independently, 73 is an external semiconductor memory element,
Reference numerals 74, 75, 76, and 77 denote sensors for detecting the temperature of each part of the refrigerator (not shown).

Next, the specific operation of the circuit will be described.

The microcomputer 69 provided on the substrate 71, based on the temperature information detected by the sensors 74 to 77, drives each of the fan motors 52 to 53, the opening degree of the damper 58, the automatic ice maker 59, and the like. , The energization specifications of each of the heaters 61 to 64, and the rotation speed of the compressor 51 are determined by calculation. Then, in order to perform the operation specifications determined by this calculation, the microcomputer 69
Outputs a drive signal of the determined drive specification to the driver 55 for driving the fan motors 52 to 54 to drive the fan motors 52 to 54 and the driver 56 for driving the damper 58. A signal for adjusting the damper to the degree specification is output to adjust the opening degree of the damper 58, and the automatic ice maker 5
9 to output a control command signal for operating specifications of the determined automatic ice maker to the driver 57 for driving the ice tray and a pump for supplying water to the ice tray, thereby operating the automatic ice maker. Then, a rotation speed command signal of the determined rotation speed of the compressor is generated and output to the microcomputer 65 provided on the power unit circuit board 67.

The rotational speed command signal output from the microcomputer 69 is insulated by the insulating element 70 provided on the board 67 and is input to the microcomputer 65 provided on the board 67. Here, the same applies when the insulating element 70 is provided on the substrate 71. The microcomputer 65 provided on the board 67 is provided with a motor terminal voltage detection resistor 43 for controlling the DC brushless motor 50 built in the compressor 51 to the commanded rotation speed calculated by the microcomputer 69 provided on the board 71. An inverter circuit based on a magnetic pole position signal of a rotor (not shown) of the DC brushless motor 50 in which a comparator 49 combines a motor terminal voltage detection signal detected by .about.48 and a signal detected by the motor applied DC voltage detection resistors 15 and 16 with a comparator 49. A drive signal for sequentially switching the semiconductor switching elements 18 to 23 in 17 is output to a driver 30 for driving an inverter circuit. The driver 30 includes a microcomputer 65
The input drive signal is output to the inverter circuit 17 to control the DC brushless motor 50 to the previously determined rotation speed.

In this case, when the DC brushless motor is at a certain rotation speed or less, the microcomputer 65 sends a DC voltage command for making the DC voltage 150 V, for example, to the transistor 68 as the first control mode. The signal is output to the power factor improvement control circuit 31 via the power factor improvement control circuit 31 via the DC voltage detection resistors 13 and 14 (arbitrarily without the transistor 68). The power supply voltage signal V detected by the power supply voltage detection resistor so that the signal has a DC voltage value.
s and the power supply current signal I detected from the power supply current detection resistor 12.
A drive signal for controlling the semiconductor switching element 8 in the PAM control booster circuit 5 is output from the PAM control booster circuit 5, and the current flowing through the power supply current detection resistor 12 in the PAM control circuit 5 is detected by the power supply voltage detection resistors 10 and 11. The power factor improvement control is performed so as to be similar to the detection signal Vs, and the voltage obtained by the energy storage effect of the reactor 6 by the switching of the switching element 8 through the backflow prevention diode 7 so as to obtain an arbitrary DC voltage. The voltage is supplied to the smoothing capacitor 9 and the inverter circuit 17
The voltage of V is PWM-controlled, and the DC brushless motor is controlled to an arbitrary rotation speed.

When the DC brushless motor is at a certain rotational speed or higher, a signal for increasing or decreasing the DC voltage is output from the microcomputer 65 so that the DC brushless motor has an arbitrary rotational speed as a second operation mode.
In the M control circuit 5, the DC brushless motor is controlled at an arbitrary rotation speed by PAM control for supplying a voltage at which the DC brushless motor has an arbitrary rotation speed to the smoothing capacitor 9.

In both the first operation mode and the second operation mode, the microcomputer 65 controls the current signal detected by the current detection resistor 72 and the DC signal detected by the DC voltage detection resistors 15 and 16. The voltage signal is monitored, and if the current value or the DC voltage value exceeds a certain set value, it is determined that the state is abnormal, and the DC brushless motor 50
Is stopped, the PAM control is also stopped, and a signal notifying the abnormal state is output to the microcomputer 69.
Also, the microcomputer 65 determines that an abnormal state occurs when an abnormality occurs in the compressor 51 or the DC brushless motor 50 and normal control cannot be performed, and outputs a signal notifying the abnormal state to the microcomputer 69.

The power board 67 has an external connection terminal 72 for connection to the outside, in addition to the connection to the refrigerator control board 71. This is the microcomputer 65
Is forced to be D separately from the normal refrigerator control mode.
A mode for operating the C brushless motor is provided so that the DC brushless motor can be operated without the refrigerator control board 71. The microcomputer 65 controls the DC brushless motor 50 at a rotation speed corresponding to the relationship shown in FIG. 5 as an example by inputting a rotation speed command of the DC brushless motor 50 from the external connection terminal 72 as an analog signal of 0 to 5 V, for example. I do. Further, the microcomputer 65 has a control state at each time, for example, a rotation speed of a rotation speed command input by the microcomputer 65, a rotation speed under control, a DC voltage value, a current value, PWM.
In the case of the control mode, a signal notifying the chopper duty of the PWM control and the like is output to the external connection terminal 72. Therefore, the power unit board 67 can easily control the DC brushless motor 50 at an arbitrary rotation speed by connecting a simple external circuit (not shown) or a DC voltage power supply (not shown) to the external connection terminal.

The external connection terminal 72 is connected to a personal computer or the like (not shown). In this case, the DC brushless motor 5
The number of rotations of 0 can be arbitrarily set, including the pattern of the change in the number of rotations, and the operating status of the power unit substrate 67, such as the number of rotations, voltage, current, chopper duty, is monitored and recorded in real time. Furthermore, external connection terminal 7
When a personal computer is connected to the PC 2, the personal computer sets the motor constants that need to be set for each DC brushless motor, the overvoltage threshold and the overcurrent threshold for judging abnormalities in voltage and current, and the like. It also has a function of changing the set value stored in the external storage element 73 to be stored. Thus, the development and evaluation of the DC brushless motor 50 and the compressor 51 alone can be performed efficiently.

Next, an example of mounting the refrigerator control device of the present invention on a refrigerator will be described with reference to FIG.

FIG. 6 is a drawing of the refrigerator as viewed from the back,
78 is a refrigerator, 79 is a refrigerator control board storage section, 80 is a condenser, 81 is a fan having a built-in fan motor 52, 82
Denotes a power unit substrate storage unit, and 83 denotes a refrigerator machine room.

The power unit board 67 is a separate board from the refrigerator control unit, and the number of insulating elements is greatly reduced, so that the size is reduced. Therefore, the power unit substrate 67 is disposed, for example, in the dead space of the machine room 83 of the refrigerator shown in FIG. 6 so that the space can be effectively used. Further, when the power part board 67 is disposed in the machine room, the distance from the power part board to the DC brushless motor 50 built in the compressor 51 becomes very short. Since the motor wires of the UVW phase from the DC brushless motor to the DC brushless motor 50 can be shortened, and the wiring through which the motor current including the high frequency component flows becomes shorter, the noise component generated as the whole refrigerator control device is suppressed. Further, the refrigerator control device of the present invention constitutes a refrigerator by arranging a heat-generating portion or a heat-radiating fin portion of a power component in the power portion substrate 67 that requires heat radiation on a floor surface or a wall surface in a machine room. An iron plate can be used as a heat radiator, and furthermore, a fan 81 for promoting heat radiation of the compressor 51 and the condenser 80 is provided in the machine room 83 of the refrigerator. The cooling air has a structure that can be used simultaneously for cooling the power unit substrate.

The power unit substrate 67 can be formed as a single unit, for example, as a module. In this case, the size can be further reduced, and the degree of freedom in mounting increases.

Since the power supply for the control element is also supplied from the power supply 66 in the power section board, the refrigerator control board 71 does not need a power supply circuit for creating the power supply for the control element. Can be made very small because it is composed of control elements. Therefore, in FIG. 6, although the control board storage section 79 is provided on the back of the refrigerator, a small dead space of the refrigerator can be used, and even if there is no dead space, control can be performed by securing a small space when designing the refrigerator. The substrate 71 can be mounted, and the internal volume ratio of the refrigerator can be improved.

Further, in the refrigerator control device of the present invention, since the power section circuit 67 can be arranged near the compressor,
Radiated noise generated from the wiring material through the iron plate surrounding the refrigerator because there is no need to route power wiring that transmits high currents, high voltages, or voltages and currents containing high-frequency components in the refrigerator insulation. Also suppress.

FIG. 1 shows an embodiment of the refrigerator of the present invention. In FIG. 1, a connection line for connecting the power section board 67 and the control section board 71 is composed of two control board power supply lines and two communication lines. However, if the voltage required by the control unit board 71 is plural, it is necessary to increase the voltage. If the communication program of the microcomputer 65 and the microcomputer 70 is simply executed, a plurality of communication lines are required. It is only necessary to increase the number, and the power supply and communication information transmission means include:
For example, there is a means for superimposing communication information on a constant voltage of a power supply line, and the number of connection lines is not particularly limited.

In this embodiment, the circuit configuration shown in FIG. 1 has been mainly described. However, a similar effect can be obtained in a PWM control type inverter refrigerator control device which does not perform PAM control as shown in FIG.

In the refrigerator control device of the present invention,
In particular, the use of the power section circuit for controlling the DC brushless motor is not limited to refrigerators, but can be widely applied to small general-purpose inverters and other motor control devices.

[0035]

As described above, according to the refrigerator control apparatus of the present invention, the power section for controlling the motor for the compressor can be mounted near the compressor, so that the power system wiring is reduced as much as possible. In addition to suppressing the amount of noise generated to a very low level, the power system wiring that was conventionally routed in the insulation of the refrigerator is eliminated,
Radiated noise can also be suppressed, and as a result, noise suppression components can be reduced, and downsizing and cost reduction can be achieved.

Further, since the power unit substrate of the present invention can be operated independently, the motor unit and the compressor unit can be efficiently developed, and the refrigerator program can be similarly efficiently developed. .

Further, in the refrigerator control device of the present invention, since the power unit circuit board and the refrigerator control board can each be downsized,
The internal volume ratio of the refrigerator can be improved.

The power board of the present invention can be widely applied not only to refrigerator control but also to various fields for DC brushless motor control.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing an embodiment of a refrigerator control device according to the present invention.

FIG. 2 is a circuit block diagram showing one embodiment of a refrigerator control device according to the present invention.

FIG. 3 is a circuit block diagram showing one embodiment of a conventional refrigerator control device.

FIG. 4 is a circuit block diagram showing one embodiment of a conventional refrigerator control device.

FIG. 5 is a characteristic diagram showing one embodiment of a command signal at the time of forcible operation of a power unit according to the present invention.

FIG. 6 is a mounting diagram showing one embodiment of a mounting method of the refrigerator control device of the present invention.

[Explanation of symbols]

1: commercial power supply, 2: common mode filter circuit, 3: normal mode filter circuit, 4: bridge diode,
5 Boost circuit, 6 Choke coil, 7 Backflow prevention diode, 8 Semiconductor switching element, 9, 9-2 Smoothing capacitor, 10, 11 Power supply voltage detection resistor, 12
Power supply current detection resistors, 13, 14 ... DC voltage detection resistors, 1
5, 16: Voltage detection resistors for generating magnetic pole position detection signals, 17
... Inverter circuit, 18-23 ... Semiconductor switching element, 24-29 ... Reflux diode, 30 ... Inverter drive circuit, 31 ... Power factor improvement control circuit, 32-42 ... Insulating element, 43-48 ... Motor terminal voltage detection resistor, 49 ...
Comparator, 50: DC brushless motor, 51: Compressor,
52 to 54: fan motor, 55: fan motor driver, 56: damper driver, 57: automatic ice machine driver, 58: damper, 59: automatic ice machine, 60: heater driver, 61 to 64: heater, 65: microcomputer 66, power supply circuit, 67, substrate, 68, transistor, 69, microcomputer, 70, insulating element, 7
DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 72 ... External connection terminal, 73 ... Semiconductor memory element, 74-77 ... Sensor, 78 ... Refrigerator, 79 ... Control part circuit storage part, 80 ... Condenser, 81 ... Fan, 82 ... Power part substrate storage part 83, a machine room; 84, a power factor improving reactor; 85, a condenser.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Koji Murayama, Inventor 800, Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Prefecture Inside the Cooling and Refrigerating Business Dept., Hitachi, Ltd. (72) Inventor Nobuaki Arakawa 800, Tomita, Ohira-machi, Ohira-cho, Shimotsuga-gun, Tochigi Prefecture F-term (ref.) NA01 NA03 NA06 NA19 NA21 PA01 PA04 PA06 5H007 AA01 BB06 CA01 CB05 CC03 CC12 DB01 DB12 DC05 EA02 HA03 HA04 HA07

Claims (1)

[Claims] An inverter circuit comprising six semiconductor switching elements connected in a three-phase bridge, a freewheeling diode connected in anti-parallel to said semiconductor switching elements, and a refrigerator control comprising a drive circuit for said inverter circuit. A refrigerator control device, wherein the inverter circuit portion and a control portion that performs control unique to the refrigerator are electrically separated.