JP2008304154A - Refrigerator having motor driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerator having an inverter protective device capable of eliminating a voltage detecting circuit, capable of largely miniaturizing the circuit, capable of reducing even a useless loss, and capable of further saving energy, since input increases, since the loss is also large, since the voltage detecting circuit becomes a large hindrance when miniaturizing an inverter. <P>SOLUTION: This refrigerator has an under-voltage determining circuit 27 for determining that an AC power source 1 is under-voltage when present duty is reference duty or more, by comparing optionally set reference duty with the present duty, when the present temperature is the reference temperature or less, by comparing the optionally set reference temperature with the present temperature in any detecting circuit of a storage inside temperature detecting circuit 14 and an outside air temperature detecting circuit 12, and can also reduce the useless loss by eliminating the voltage detecting circuit by stopping output of the inverter when the under-voltage determining circuit 27 determines as the under-voltage. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a refrigerator provided with a motor drive device that drives and controls a brassless motor by an inverter.

  Conventionally, a motor driving device that drives and controls a brassless motor of this type of compressor for a refrigerator by an inverter has been disclosed (for example, see Patent Document 1).

  The prior art will be described with reference to the drawings. FIG. 10 is a block diagram of a conventional brushless DC motor driving apparatus.

  In FIG. 10, a commercial power source 101 is an AC power source having a frequency of 50 Hz or 60 Hz and a voltage of 100 V in Japan.

  The rectifier circuit 102 is a circuit that converts the AC voltage of the commercial power supply 101 into a DC voltage. The rectifier circuit 102 is composed of rectifier diodes 102a to 102d and a smoothing electrolytic capacitor 102e that are bridge-connected. In the circuit shown in FIG. Can do.

  The inverter circuit 103 has a three-phase bridge configuration including six switch elements 103a, 103b, 103c, 103d, 103e, and 103f. Each switch element includes a diode for return current in the reverse direction of each switch element, but this is omitted in the figure.

  The brushless DC motor 104 includes a rotor 104a having a permanent magnet and a stator 104b having a three-phase winding. When the three-phase alternating current generated by the inverter 103 flows through the three-phase winding of the stator 104b, the rotor 104a can be rotated. The rotational movement of the rotor 104a is changed to a reciprocating movement by a crankshaft (not shown), and a piston (not shown) reciprocates in a cylinder (not shown) to compress the refrigerant. Drive.

  A microcomputer 105 that controls the entire apparatus performs control and protection control of each power element of the inverter 103.

  The drive circuit 106 controls on / off of each power element of the inverter 103 by a signal from the microcomputer 105.

  The voltage detection circuit 107 detects the output voltage of the rectifier circuit 102 and detects the state of the AC power supply 101 that is an input. In this voltage detection circuit, when there is an undervoltage, overvoltage, instantaneous interruption or the like of the AC power supply, a signal is sent to the microcomputer 105, and the microcomputer 105 performs appropriate processing such as inverter stop.

  FIG. 11 is a circuit diagram of the voltage detection circuit 107. In FIG. 11, the output voltage of the rectifier circuit 102 is divided by the resistors 108 and 109. This divided voltage is compared with the reference voltage A111 by the comparator 110, and when the divided voltage <the reference voltage A, an undervoltage signal is output, and it is detected that the input voltage is lowered.

  Further, the divided voltage is compared with the reference voltage B113 by the comparator 112, and an overvoltage signal is output when the divided voltage> the reference voltage B, and it is detected that the input voltage has risen abnormally.

In response to these signals, the microcomputer 105 performs appropriate protection processing including inverter stop.
JP-A-11-103585

  However, the conventional configuration has the following problems.

  Although it is possible to detect that the input voltage is decreasing and the input voltage is abnormally increasing, circuit loss occurs because the DC voltage is divided using a resistor.

  For example, when the voltage of the AC power supply 101 is AC100V, the output of the rectifier circuit 102 is DC140V. Here, if the current flowing through the voltage dividing resistor is designed to be 5 mA, the series combined resistance value of the resistor 108 and the resistor 109 is 28 kΩ, and the loss (heat loss) at the resistor is 0.7 W.

  Considering the above example, the resistor requires a resistor of at least 2 W and generates heat, which is a major obstacle when the inverter is downsized. Moreover, since the loss is large, there is a problem that the input increases.

  It is an object of the present invention to provide a refrigerator including an inverter protection device that can omit the voltage detection circuit, greatly reduce the size of the circuit, reduce wasteful loss, and realize further energy saving. .

  In order to solve the above-described conventional problems, a refrigerator including the motor driving device of the present invention includes a reference temperature arbitrarily set in a detection circuit of either the internal temperature detection circuit or the outside air temperature detection circuit, and the current temperature. If the current temperature is lower than the reference temperature, and the arbitrarily set reference duty is compared with the current duty. If the current duty is equal to or higher than the reference duty, the AC power supply is undervoltage. And an undervoltage determination circuit for determining that the output of the inverter can be stopped when the undervoltage determination circuit determines that the voltage is insufficient.

  Further, the refrigerator equipped with the motor driving device of the present invention compares the reference temperature arbitrarily set in the detection circuit of either the inside temperature detection circuit and the outside temperature detection circuit with the current temperature, An overvoltage determination circuit that compares the current duty with a reference duty that is arbitrarily set when the temperature is equal to or higher than the reference temperature, and determines that the AC power supply is overvoltage if the current duty is less than or equal to the reference duty The output of the inverter can be stopped when the overvoltage determination circuit determines that the voltage is overvoltage.

  Further, the refrigerator equipped with the motor driving device of the present invention compares the reference temperature arbitrarily set in the detection circuit of either the inside temperature detection circuit and the outside temperature detection circuit with the current temperature, If the temperature is below the reference temperature and the rotation speed set arbitrarily is compared with the current rotation speed, and if the current rotation speed is below the reference rotation speed, it is insufficient to determine that the AC power supply is undervoltage A voltage determination circuit, and when the undervoltage determination circuit determines that the voltage is insufficient, the output of the inverter can be stopped.

  Further, the refrigerator equipped with the motor driving device of the present invention compares the reference temperature arbitrarily set in the detection circuit of either the inside temperature detection circuit and the outside temperature detection circuit with the current temperature, The temperature is equal to or higher than the reference temperature, and the reference rotation speed set arbitrarily is compared with the current rotation speed. If the current rotation speed is equal to or higher than the reference rotation speed, it is determined that the AC power supply is overvoltage. And an overvoltage determination circuit that stops the output of the inverter when the overvoltage determination circuit determines that the voltage is overvoltage.

  Further, the refrigerator equipped with the motor driving device of the present invention compares the reference temperature arbitrarily set in the detection circuit of either the inside temperature detection circuit and the outside temperature detection circuit with the current temperature, If the temperature is below the reference temperature and the reference overlap angle set arbitrarily and the current overlap angle are compared, and the current overlap angle is greater than or equal to the reference overlap angle, the AC power supply is undervoltage And an undervoltage determination circuit for determining that the output of the inverter can be stopped when the undervoltage determination circuit determines that the voltage is insufficient.

  Further, the refrigerator equipped with the motor driving device of the present invention compares the reference temperature arbitrarily set in the detection circuit of either the inside temperature detection circuit and the outside temperature detection circuit with the current temperature, If the temperature is equal to or higher than the reference temperature and the reference overlap angle set arbitrarily is compared with the current overlap angle, and the current overlap angle is less than the reference overlap angle, the AC power supply is overvoltage An overvoltage determination circuit for determining that there is an overvoltage, and when the overvoltage determination circuit determines that the voltage is overvoltage, the output of the inverter can be stopped.

  As a result, the voltage detection circuit can be omitted, the circuit can be greatly reduced in size, wasteful loss can be reduced, and a refrigerator equipped with an inverter protection device that can realize further energy savings.

  In the refrigerator equipped with the motor drive device of the present invention, the voltage detection circuit can be omitted, and the circuit can be greatly reduced in size. As a result, an inexpensive refrigerator can be provided.

  Moreover, the refrigerator provided with the motor drive device of the present invention can reduce useless loss and can realize further energy saving. As a result, a refrigerator with low running cost can be provided.

  The invention according to claim 1 is an internal temperature detection circuit provided inside the refrigerator, an outside temperature detection circuit provided outside the refrigerator, a compressor, and an AC power source for driving the compressor. A rectifying circuit that rectifies, an inverter that converts the output of the rectifying circuit into an alternating current, a brushless DC motor that is rotated by the inverter, a position detection circuit that detects a rotational position of a rotor of the brushless DC motor, and a position detection circuit The commutation circuit that determines the operation of each power element of the inverter based on the signal, the speed detection circuit that detects the rotational speed from the output of the position detection circuit, and the rotational speed and the set speed from the speed detection circuit match. The duty setting circuit that adjusts the duty so as to be arbitrarily set in the detection circuit of any one of the internal temperature detection circuit and the outside temperature detection circuit If the current temperature is lower than the reference temperature, the current reference temperature is compared with the current duty, and if the current duty is greater than the reference duty An undervoltage determination circuit that determines that the AC power supply is undervoltage, and the inverter output is stopped when the undervoltage determination circuit determines that the undervoltage is undervoltage, so that the refrigerator is inexpensive and low in running cost. Can be provided.

  The invention described in claim 2 is an internal temperature detection circuit provided inside the refrigerator, an outside temperature detection circuit provided outside the refrigerator, a compressor, and an AC power source for driving the compressor. A rectifying circuit that rectifies, an inverter that converts the output of the rectifying circuit into an alternating current, a brushless DC motor that is rotated by the inverter, a position detection circuit that detects a rotational position of a rotor of the brushless DC motor, and a position detection circuit The commutation circuit that determines the operation of each power element of the inverter based on the signal, the speed detection circuit that detects the rotational speed from the output of the position detection circuit, and the rotational speed and the set speed from the speed detection circuit match. The duty setting circuit that adjusts the duty so as to be arbitrarily set in the detection circuit of any one of the internal temperature detection circuit and the outside temperature detection circuit If the current temperature is equal to or higher than the reference temperature, and the reference duty set arbitrarily is compared with the current duty. An overvoltage determination circuit for determining that the AC power supply is overvoltage, and providing an inexpensive and low running cost refrigerator by stopping the output of the inverter when the overvoltage determination circuit determines that the overvoltage is overvoltage. Can do.

  The invention according to claim 3 is an internal temperature detection circuit provided inside the refrigerator, an outside temperature detection circuit provided outside the refrigerator, a compressor, and an AC power source for driving the compressor. A rectifying circuit that rectifies, an inverter that converts the output of the rectifying circuit into an alternating current, a brushless DC motor that is rotated by the inverter, a position detection circuit that detects a rotational position of a rotor of the brushless DC motor, and a position detection circuit One of a commutation circuit that determines the operation of each power element of the inverter by a signal, a speed detection circuit that detects a rotational speed from an output of the position detection circuit, the internal temperature detection circuit, and the outside air temperature detection circuit The reference temperature arbitrarily set in the detection circuit is compared with the current temperature, the current temperature is lower than the reference temperature, and the arbitrarily set rotation speed and current An undervoltage determination circuit that compares rotation speeds and determines that the AC power supply is undervoltage if the current rotation speed is equal to or less than a reference rotation speed, and the undervoltage determination circuit is undervoltage When it is determined, by stopping the output of the inverter, it is possible to provide a refrigerator that is inexpensive and low in running cost.

  The invention according to claim 4 is an internal temperature detection circuit provided inside the refrigerator, an outside temperature detection circuit provided outside the refrigerator, a compressor, and an AC power source for driving the compressor. A rectifying circuit that rectifies, an inverter that converts the output of the rectifying circuit into an alternating current, a brushless DC motor that is rotated by the inverter, a position detection circuit that detects a rotational position of a rotor of the brushless DC motor, and a position detection circuit One of a commutation circuit that determines the operation of each power element of the inverter by a signal, a speed detection circuit that detects a rotational speed from an output of the position detection circuit, the internal temperature detection circuit, and the outside air temperature detection circuit The reference temperature arbitrarily set in the detection circuit is compared with the current temperature, the current temperature is equal to or higher than the reference temperature, and the reference rotation speed arbitrarily set An overvoltage determination circuit that determines that the AC power supply is overvoltage if the current rotation speed is equal to or higher than a reference rotation speed, and determines that the overvoltage determination circuit is overvoltage. In this case, by stopping the output of the inverter, it is possible to provide a refrigerator that is inexpensive and low in running cost.

  The invention according to claim 5 is an internal temperature detection circuit provided inside the refrigerator, an outside temperature detection circuit provided outside the refrigerator, a compressor, and an AC power source for driving the compressor. A rectifying circuit that rectifies, an inverter that converts the output of the rectifying circuit into an alternating current, a brushless DC motor that is rotated by the inverter, a position detection circuit that detects a rotational position of a rotor of the brushless DC motor, and a position detection circuit The commutation circuit that determines the operation of each power element of the inverter based on the signal, the speed detection circuit that detects the rotational speed from the output of the position detection circuit, and the rotational speed and the set speed from the speed detection circuit match. A duty setting circuit for adjusting the duty and a rotation speed detected by the speed detection circuit even when the duty ratio is changed by the duty setting circuit. An overlap angle setting circuit for adding / subtracting an overlap angle when the rotation speed is not reached, and a reference temperature and a current temperature arbitrarily set in any one of the detection circuit of the internal temperature detection circuit and the outside air temperature detection circuit, If the current temperature is below the reference temperature, and the reference overlap angle set arbitrarily is compared with the current overlap angle, the current overlap angle is greater than or equal to the reference overlap angle. An undervoltage determination circuit for determining that the AC power supply is undervoltage, and stopping the output of the inverter when the undervoltage determination circuit determines that the undervoltage is undervoltage, so that the running cost is low. A refrigerator can be provided.

  The invention according to claim 6 is an internal temperature detection circuit provided inside the refrigerator, an outside temperature detection circuit provided outside the refrigerator, a compressor, and an AC power source for driving the compressor. A rectifying circuit that rectifies, an inverter that converts the output of the rectifying circuit into an alternating current, a brushless DC motor that is rotated by the inverter, a position detection circuit that detects a rotational position of a rotor of the brushless DC motor, and a position detection circuit The commutation circuit that determines the operation of each power element of the inverter based on the signal, the speed detection circuit that detects the rotational speed from the output of the position detection circuit, and the rotational speed and the set speed from the speed detection circuit match. A duty setting circuit for adjusting the duty and a rotation speed detected by the speed detection circuit even when the duty ratio is changed by the duty setting circuit. An overlap angle setting circuit for adding / subtracting an overlap angle when the rotation speed is not reached, and a reference temperature and a current temperature arbitrarily set in any one of the detection circuit of the internal temperature detection circuit and the outside air temperature detection circuit, If the current temperature is equal to or higher than the reference temperature, and the reference overlap angle set arbitrarily is compared with the current overlap angle, the current overlap angle is less than the reference overlap angle. An overvoltage determination circuit for determining that the AC power supply is overvoltage, and providing an inexpensive and low running cost refrigerator by stopping the output of the inverter when the overvoltage determination circuit determines that the overvoltage is overvoltage. Can do.

  Hereinafter, embodiments of a refrigerator according to the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a block diagram of a refrigerator provided with a motor drive device according to Embodiment 1 of the present invention.

  In FIG. 1, a commercial power source 1 is an AC power source having a frequency of 50 Hz or 60 Hz and a voltage of 100 V in Japan.

  The rectifier circuit 2 converts the AC voltage of the commercial power source 1 into a DC voltage. The rectifier circuit 2 includes rectifier diodes 2a to 2d connected in a bridge and an electrolytic capacitor 2e for smoothing. When the circuit shown in FIG. 1 is a voltage doubler rectifier circuit, a DC voltage 280V is obtained from an AC 100V input of the commercial power source 1. Can do.

  The inverter circuit 3 has a three-phase bridge configuration including six switch elements 3a, 3b, 3c, 3d, 3e, and 3f. Each switch element includes a diode for return current in the reverse direction of each switch element, but this is omitted in the figure.

  The brushless DC motor 4 includes a rotor 4a having a permanent magnet and a stator 4b having a three-phase winding. When the three-phase alternating current generated by the inverter 3 flows in the three-phase winding of the stator 4b, the rotor 4a can be rotated.

  The compression element 5 is connected to the shaft of the rotor 4a of the brushless DC motor 4 and has a well-known configuration for sucking refrigerant gas, compressing it, and discharging it. The brushless DC motor 4 and the compression element 5 are accommodated in the same hermetic container to constitute the compressor 6.

  The discharge gas compressed by the compressor 6 constitutes a refrigeration system that returns to the suction of the compressor 6 through the condenser 7, the decompressor 8, and the evaporator 9. Since the container 9 absorbs heat, it can be cooled and heated.

  In addition, a heat exchanger may be further accelerated | stimulated using a fan etc. for the condenser 7 and the evaporator 9 as needed. Moreover, in this Embodiment 1, it has demonstrated by the case where it is set as the refrigerator 10 with the refrigerating system, and is set as the structure cooled with the evaporator 9 in the refrigerator 10. FIG.

  The outside air temperature sensor 11 is an existing temperature sensor composed of a thermistor or the like provided on the outer surface of the refrigerator 10, and the outside air temperature detection circuit 12 detects the outside air temperature.

  The internal temperature sensor 13 is an existing temperature sensor composed of a thermistor or the like provided in the refrigerator or in the vicinity of the evaporator 9 cooled by the evaporator 9 in the refrigerator 10. Is detected.

  The load state determination circuit 15 determines the cooling load by the evaporator 9 in the refrigerator 10 from the temperature of one or both of the outside air temperature detection circuit 12 and the inside temperature detection circuit 14. In the first embodiment, the load amount when the outside temperature detection circuit 12 detects 30 ° C. or more or the inside temperature detection circuit 14 detects 30 ° C. or more is “heavy”, the outside temperature detection circuit 12 is less than 30 ° C. and 15 The load when the temperature detection circuit 14 detects that the temperature is above -20 ° C or less than -20 ° C, and the load when the outside temperature detection circuit 12 detects that the temperature is less than 15 ° C. The case where the state determination circuit 15 determines will be described below. In general, the temperature detection by the outside air temperature detection circuit 12 and the internal temperature detection circuit 14 and the determination by the load state determination circuit 15 are performed by the refrigerator control microcomputer 16 and have already been used as means for efficiently cycling the refrigeration system. It is generally used.

  The position detection circuit 17 is a circuit that detects the rotational position of the rotor 4a of the brushless DC motor 4, and employs a sensorless system that detects the relative position of the rotor 4a from the back electromotive voltage of the motor.

  The commutation circuit 18 determines which power element of the inverter 3 is turned on based on the position signal of the rotor 4 a of the brushless DC motor 4 from the position detection circuit 17. Generally, it is determined by logic.

  The duty setting circuit 19 employs a method of modulating the output voltage of the inverter 3 using a PWM (pulse width modulation) method. The PWM method controls the high / low voltage by the ratio of the ON width in the pulse period (this ratio is called duty). The smaller the duty (minimum 0%), the lower the output voltage of the inverter 3, and the duty Is larger (minimum 100%), the output voltage of the inverter 3 becomes higher. The reciprocal of the pulse period is called a carrier frequency. Generally, the carrier frequency of an inverter used for driving a motor is generally 2 kHz to 20 kHz.

  The synthesis circuit 20 synthesizes the duty signal set by the duty setting circuit 19 and the ON state of the power element determined by the commutation circuit 18 by the synthesis circuit 20 and uses the drive circuit 21 to turn on the power element of the inverter 3. / Off control.

  The speed detection circuit 22 measures the output cycle of the position detection circuit 17 and detects the actual rotation speed of the motor. The rotational speed of the rotor 4 a of the brushless DC motor 4 completely matches the signal from the position detection circuit 17.

  The speed setting circuit 23 sets how much the rotational speed of the brushless DC motor 4 is to be set. Generally, it is generally set by a command from the load state determined by the load state determination circuit 15 of the refrigerator control microcomputer 16. The set speed set by the speed setting circuit 23 and the actual rotation speed detected by the speed detection circuit 22 are compared by the speed comparison circuit 24, and the result is sent to the duty setting circuit 19. In the duty setting circuit 19, the duty is increased when the actual rotational speed is lower than the set speed, and the rotational speed is increased. Conversely, when the actual rotational speed is higher than the set speed, the duty is decreased and the rotational speed is adjusted. . When the actual rotational speed matches the set speed, the duty is fixed so that the rotational speed does not change.

  The standard duty setting circuit 25 sets the standard duty according to the set speed of the speed setting circuit 23 and the load state determined by the load state determination circuit 15. The standard duty indicates how much the duty is operated when the input voltage is in an undervoltage state or an overvoltage state based on the rotation speed and the load state, and can be generally set by the motor design.

  The duty determination circuit 26 determines whether or not the actual duty output from the duty setting circuit 19 is within a predetermined range of the standard duty indicated by the standard duty setting circuit 25.

  The undervoltage determination circuit 27 sets an undervoltage and sends an abnormal signal to the speed setting circuit 23 when the duty determination circuit 26 determines that the actual duty is larger than the standard duty set by the standard duty setting circuit 25. Then, the inverter circuit is protected by setting the set speed to 0 (stop).

  When the duty determination circuit 26 determines that the actual duty is smaller than the standard duty set by the standard duty setting circuit 25, the overvoltage determination circuit 28 sets an overvoltage and sends an abnormal signal to the speed setting circuit 23. The inverter circuit is protected by setting the set speed to 0 (stop).

  The inverter microcomputer 29 performs appropriate processes for realizing these processes.

  In the above configuration, the operation will be described below with reference to FIGS.

  FIG. 2 is a flowchart showing the operation in the first embodiment.

  FIG. 3 is a characteristic diagram showing the standard duty in the first embodiment.

  First, in STEP 100, the load state determination circuit 15 determines the load state of the refrigerator 10, and if it is determined that the cooling of the evaporator 9 needs to be increased or decreased, the process proceeds to STEP 101, where it is determined that the current state is acceptable. If so, return to STEP 100.

  In STEP 101, the rotational speed of the brushless DC motor 4 is controlled from the position detection circuit 17, the commutation circuit 18, the duty setting circuit 19, the synthesis circuit 20, the drive circuit 21, the speed detection circuit 22, and the speed comparison circuit 24, and the process proceeds to STEP 102.

  In STEP102, based on the load state of the refrigerator 10 determined by the load state determination circuit 15, the standard duty setting circuit 25 indicates how much duty is operated when the input voltage is in an undervoltage state or an overvoltage state. move on. At this time, if the load state of the refrigerator 10 determined by the load state determination circuit 15 in the characteristic diagram of FIG. 3 is “light”, the duty amount in the rated voltage state is D1 [%], and the duty amount in the overvoltage state is D0 [%]. ] Below, the duty amount in the undervoltage state is D3 [%] or more (D0 <D1 <D3), and if the load state is “medium”, the duty amount in the rated voltage state is D4 [%], and the duty amount in the overvoltage state Is D2 [%] or less, the duty amount in the undervoltage state is D6 [%] or more (D2 <D4 <D6), and if the load state is “heavy”, the duty amount in the rated voltage state is D7 [%], overvoltage The state duty amount is set to D5 [%] or less, and the undervoltage state duty amount is set to D8 [%] or more (D5 <D7 <D8). However, the slopes of the rated voltage state, the overvoltage state, and the undervoltage state are not limited to this.

  In STEP 103, the duty determination circuit 26 advances to STEP 104 if the actual duty output from the duty setting circuit 19 is D3 [%] or more when the load state is “light”, and to STEP 105 if it is less than D3 [%]. When the load state is “medium”, if D6 [%] or more, the process proceeds to STEP 104. If less than D6 [%], the process proceeds to STEP 105, and if the load state is “heavy”, it is D8 [%] or more. On the other hand, the process proceeds to STEP 104, and if it is less than D8 [%], the process proceeds to STEP 105.

  In STEP 104, the undervoltage determination circuit 27 sets the undervoltage to the speed setting circuit 23, sends an abnormal signal to the speed setting circuit 23, and sets the setting speed to 0 (stops), thereby protecting the inverter circuit and returning to STEP100.

  In STEP 105, the duty determination circuit 26 returns to STEP 100 if the actual duty output from the duty setting circuit 19 is D0 [%] or more when the load state is “light”, and returns to STEP 106 if it is less than D0 [%]. If the load state is “medium”, if D2 [%] or more, the process returns to STEP 100. If less than D2 [%], the process proceeds to STEP 106, and if the load state is “heavy”, if D5 [%] or more. Returning to STEP 100, if it is less than D5 [%], proceed to STEP 106.

  In STEP 106, an overvoltage is set by the overvoltage determination circuit 28, an abnormal signal is sent to the speed setting circuit 23, and the set speed is set to 0 (stop), thereby protecting the inverter circuit and returning to STEP100.

  As described above, in the first embodiment, the outside temperature sensor 11, the outside temperature detection circuit 12, the inside temperature sensor 13, the inside temperature detection circuit 14, the load state determination circuit 15, and the refrigerator control according to the present invention. Since the microcomputer 16 uses what is already provided, and the series of inverter operations can be realized by the software of the inverter microcomputer 29, all the conventional voltage detection circuits can be omitted, and the number of parts can be reduced. This has a great effect on energy saving by reducing costs by reducing waste and reducing wasteful loss.

  Therefore, it is possible to provide a refrigerator that is inexpensive and low in running cost.

(Embodiment 2)
FIG. 4 is a block diagram of a refrigerator provided with a motor drive device according to Embodiment 2 of the present invention. 4 that are the same as those in FIG. 1 have already been described, and will not be described.

  The standard speed setting circuit 30 sets the standard speed according to the set speed of the speed setting circuit 23 and the load state determined by the load state determination circuit 15. Standard speed refers to the case where the rotational speed is delayed even if the duty exceeds the upper limit (100%) due to the high load state or undervoltage state from the rotational speed and load state, or the motor is driven due to the light load state or overvoltage state. This shows how fast the motor operates when the rotational speed advances even below the lower limit required for driving, and can be generally set by the motor design.

  The speed determination circuit 31 determines whether or not the actual speed output from the speed detection circuit 22 is within a predetermined range of the standard speed indicated by the standard speed setting circuit 30.

  The undervoltage determination circuit 32 sets an undervoltage and sends an abnormal signal to the speed setting circuit 23 when the speed determination circuit 31 determines that the actual speed is slower than the standard speed set by the standard speed setting circuit 30. Then, the inverter circuit is protected by setting the set speed to 0 (stop).

  The overvoltage determination circuit 33 sends an abnormal signal to the speed setting circuit 23 as an overvoltage when the speed determination circuit 31 determines that the actual speed is faster than the standard speed set by the standard speed setting circuit 30. The inverter circuit is protected by setting the set speed to 0 (stop).

  The inverter microcomputer 34 performs appropriate processes for realizing these processes.

  In the above configuration, the operation will be described below with reference to FIGS.

  FIG. 5 is a flowchart showing the operation in the second embodiment.

  FIG. 6 is a characteristic diagram showing the standard speed in the second embodiment.

  First, STEP 100 is the same as in the first embodiment.

  In STEP 101, the rotational speed of the brushless DC motor 4 is controlled from the position detection circuit 17, the commutation circuit 18, the duty setting circuit 19, the synthesis circuit 20, the drive circuit 21, the speed detection circuit 22, and the speed comparison circuit 24, and the process proceeds to STEP 200.

  In STEP 200, based on the load state of the refrigerator 10 determined by the load state determination circuit 15, the standard speed setting circuit 30 indicates how fast the operation is performed when the input voltage is in an undervoltage state or an overvoltage state. move on. At this time, if the load state of the refrigerator 10 determined by the load state determination circuit 15 in the characteristic diagram of FIG. 6 is “light”, the speed in the rated voltage state is V1 [r / s], and the speed in the undervoltage state is V0 [ r / s] or less, the speed in the overvoltage state is V3 [r / s] or more (V0 <V1 <V3), and if the load state is “medium”, the speed in the rated voltage state is V4 [r / s], insufficient The speed in the voltage state is V2 [r / s] or less, the speed in the overvoltage state is V6 [r / s] or more (V2 <V4 <V6), and if the load state is “heavy”, the speed in the rated voltage state is V7 [R / s], the speed in the undervoltage state is V5 [r / s] or less, and the speed in the overvoltage state is V8 [r / s] or more (V5 <V7 <V8). However, the slopes of the rated voltage state, the overvoltage state, and the undervoltage state are not limited to this.

  In STEP 201, if the actual speed output from the speed detection circuit 22 is V3 [r / s] or more when the load state is “light” by the speed determination circuit 31, the process proceeds to STEP 202, while it is less than V3 [r / s]. If YES, proceed to STEP 203. If the load state is “medium”, if V6 [r / s] or more, proceed to STEP 202. If less than V6 [r / s], proceed to STEP 203. If the load state is “heavy” If it is V8 [r / s] or more, the process proceeds to STEP 202. If it is less than V8 [r / s], the process proceeds to STEP 203.

  In STEP 202, the undervoltage is determined by the undervoltage determination circuit 32, an abnormal signal is sent to the speed setting circuit 23, and the set speed is set to 0 (stopped) to protect the inverter circuit and return to STEP100.

  In STEP 203, the speed determination circuit 31 returns to STEP 100 if the actual speed output from the speed detection circuit 22 is equal to or higher than V0 [r / s] when the load state is “light”, and is less than V0 [r / s]. If there is, the process proceeds to STEP 204, and if the load state is “medium”, if V2 [r / s] or more, the process returns to STEP 100. If less than V2 [r / s], the process proceeds to STEP 204, and if the load state is “heavy”. If it is V5 [r / s] or more, the process returns to STEP 100. If it is less than V5 [r / s], the process proceeds to STEP 204.

  In STEP 204, an overvoltage is determined by the overvoltage determination circuit 33, an abnormal signal is sent to the speed setting circuit 23, and the set speed is set to 0 (stop), so that the inverter circuit is protected and the process returns to STEP100.

  As described above, in the second embodiment, the outside temperature sensor 11, the outside temperature detection circuit 12, and the inside temperature sensor 13, the inside temperature detection circuit 14, the load state determination circuit 15, and the refrigerator control according to the present invention. Since the microcomputer 16 is already equipped, and a series of inverter operations can be realized by the software of the inverter microcomputer 34, all the conventional voltage detection circuits can be omitted, and the number of parts can be reduced. This has a great effect on energy saving by reducing costs by reducing waste and reducing wasteful loss.

  Therefore, it is possible to provide a refrigerator that is inexpensive and low in running cost.

(Embodiment 3)
FIG. 7 is a block diagram of a refrigerator provided with a motor drive device according to Embodiment 3 of the present invention. 7 that are the same as those in FIG. 1 have already been described, and will not be described.

  The overlap angle setting circuit 35 increases the energization angle of the inverter circuit 3 and is set when the rotational speed of the brushless DC motor 4 does not reach the target rotational speed even when the duty reaches 100% or the set maximum duty. Even when the lower limit duty is reached, when the rotational speed of the brushless DC motor 4 exceeds the target rotational speed, the overlap angle is set by reducing the conduction angle of the inverter circuit 3 and the rotational speed of the brushless DC motor 4 is targeted. Move closer to the rotation speed.

  The combining circuit 36 combines the duty signal set by the duty setting circuit 19, the overlap angle set by the overlap angle setting circuit 35, and the ON state of the power element determined by the commutation circuit 18. The power circuit ON / OFF control of the inverter circuit 3 is performed using the drive circuit 21.

  The standard overlap angle setting circuit 37 sets a standard overlap angle according to the set speed of the speed setting circuit 23 and the load state determined by the load state determination circuit 15. Standard overlap angle means that the rotation speed is delayed even if the overlap angle exceeds the upper limit due to the high load state or undervoltage condition from the rotation speed and load state, or the overlap angle depends on the light load state or overvoltage state. This indicates how fast the motor operates when the rotational speed advances even when the motor speed is below the lower limit required for driving the motor, and can be generally set by the motor design.

  The overlap angle determination circuit 38 determines whether or not the actual overlap angle output from the overlap angle setting circuit 35 is within a predetermined range of the standard overlap angle indicated by the standard overlap angle setting circuit 37. .

  The undervoltage determination circuit 39 determines that the actual overlap angle is larger than the standard overlap angle set by the standard overlap angle setting circuit 37 by the overlap angle determination circuit 38 and sets the speed as an undervoltage. The inverter circuit is protected by sending an abnormal signal to the setting circuit 23 and setting the set speed to 0 (stop).

  The overvoltage determination circuit 40 sets an overvoltage when the overlap angle determination circuit 38 determines that the actual overlap angle is smaller than the standard overlap angle set by the standard overlap angle setting circuit 37, and the speed setting circuit. The inverter circuit is protected by sending an abnormal signal to 23 and setting the set speed to 0 (stop).

  The inverter microcomputer 41 performs appropriate processes for realizing these processes.

  In the above configuration, the operation will be described below with reference to FIGS.

  FIG. 8 is a flowchart showing the operation in the third embodiment.

  FIG. 9 is a characteristic diagram showing a standard overlap angle in the third embodiment.

  First, in STEP100, the load state determination circuit 15 determines the load state of the refrigerator 10, and when it is determined that the cooling increase or decrease of the evaporator 9 is necessary, the process proceeds to STEP300 and it is determined that the current state is acceptable. If so, return to STEP 100.

  In STEP 300, the rotational speed of the brushless DC motor 4 from the position detection circuit 17, the commutation circuit 18, the duty setting circuit 19, the overlap angle setting circuit 35, the synthesis circuit 36, the drive circuit 21, the speed detection circuit 22, and the speed comparison circuit 24. To step 301.

  In STEP301, based on the load state of the refrigerator 10 determined by the load state determination circuit 15, when the input voltage is undervoltage or overvoltage by the standard overlap angle setting circuit 37, how much overlap angle is operated And go to STEP302. At this time, if the load state of the refrigerator 10 determined by the load state determination circuit 15 in the characteristic diagram of FIG. 9 is “light”, the overlap angle in the rated voltage state is L1 [degrees], and the overlap angle in the overvoltage state is L0. [Degree] Below, the overlap angle in the undervoltage state is L3 [degree] or more (L0 <L1 <L3), and if the load state is “medium”, the overlap angle in the rated voltage state is L4 [degree], overvoltage The overlap angle in the state is less than L2 [degree], the overlap angle in the undervoltage state is more than L6 [degree] (L2 <L4 <L6), and if the load state is “heavy”, the overlap angle in the rated voltage state Is L7 [degrees], the overlap angle in the overvoltage state is not more than L5 [degrees], and the overlap angle in the undervoltage state is not less than L8 [degrees] (L5 <L7 <L8). However, the slopes of the rated voltage state, the overvoltage state, and the undervoltage state are not limited to this.

  In STEP 302, if the actual overlap angle output from the overlap angle setting circuit 35 is greater than or equal to L3 [degrees] when the load state is “light”, the overlap angle determination circuit 38 proceeds to STEP303, while L3 [degrees]. If it is less than L6 [degrees], the process proceeds to STEP303. If it is less than L6 [degrees], the process proceeds to STEP304, and if it is less than L6 [degrees], it proceeds to STEP304. If it is greater than or equal to [degree], the process proceeds to STEP 303. If less than L8 [degree], the process proceeds to STEP 304.

  In STEP 303, an undervoltage is determined by the undervoltage determination circuit 39, an abnormal signal is sent to the speed setting circuit 23, and the set speed is set to 0 (stop), thereby protecting the inverter circuit and returning to STEP100.

  In STEP 304, the overlap angle determination circuit 38 returns to STEP 100 if the actual overlap angle output from the overlap angle setting circuit 35 is greater than or equal to L0 [degrees] when the load state is “light”, whereas L0 [degrees]. If it is less than L2 [degrees], the process goes back to STEP100. If it is less than L2 [degrees], the process goes to STEP305, and if the load condition is "heavy", the process goes to STEP5. If it is equal to or greater than [degree], the process returns to STEP 100. If it is less than L5 [degree], the process proceeds to STEP 305.

  In STEP 305, the overvoltage is determined by the overvoltage determination circuit 40, an abnormal signal is sent to the speed setting circuit 23, and the set speed is set to 0 (stopped), thereby protecting the inverter circuit and returning to STEP100.

  As described above, in the third embodiment, the outside temperature sensor 11, the outside temperature detection circuit 12, the inside temperature sensor 13, the inside temperature detection circuit 14, the load state determination circuit 15, and the refrigerator control according to the present invention. Since the microcomputer 16 uses what is already provided and the series of inverter operations can be realized by the software of the inverter microcomputer 41, all the conventional voltage detection circuits can be omitted. This has a great effect on energy saving by reducing costs by reducing waste and reducing wasteful loss. Therefore, it is possible to provide a refrigerator that is inexpensive and low in running cost.

  As described above, a refrigerator equipped with a motor drive device can omit a voltage detection circuit, and can be greatly reduced in size because the circuit can be greatly reduced in size. Can be offered cheaply. Therefore, the present invention can be applied to various devices that are equipped with a brushless DC motor regardless of whether it is inexpensive or energy-saving for home use or industrial use.

Block diagram of a refrigerator provided with a motor drive device in Embodiment 1 of the present invention The flowchart which showed operation | movement of the refrigerator provided with the motor drive device in Embodiment 1 of this invention. The characteristic figure which showed the standard duty of the refrigerator which comprised the motor drive device in Embodiment 1 of this invention Block diagram of a refrigerator equipped with a motor drive device in Embodiment 2 of the present invention The flowchart which showed the operation | movement of the refrigerator provided with the motor drive device in Embodiment 2 of this invention. The characteristic view which showed the standard speed of the refrigerator provided with the motor drive unit in Embodiment 2 of this invention Block diagram of a refrigerator provided with a motor drive device in Embodiment 3 of the present invention The flowchart which showed operation | movement of the refrigerator provided with the motor drive device in Embodiment 3 of this invention. The characteristic figure which showed the standard overlap angle of the refrigerator which comprised the motor drive unit in Embodiment 3 of this invention Block diagram of a conventional brushless DC motor drive device Circuit diagram of conventional voltage detection circuit

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Commercial power supply 2 Rectifier circuit 3 Inverter circuit 4 Brushless DC motor 6 Compressor 10 Refrigerator 12 Outside temperature detection circuit 14 Internal temperature detection circuit 17 Position detection circuit 18 Commutation circuit 19 Duty setting circuit 22 Speed detection circuit 27 Undervoltage determination circuit 28 Overvoltage determination circuit 32 Undervoltage determination circuit 33 Overvoltage determination circuit 35 Overlap angle setting circuit 39 Undervoltage determination circuit 40 Overvoltage setting circuit

Claims (6)

  An internal temperature detection circuit provided inside the refrigerator, an outside temperature detection circuit provided outside the refrigerator, a compressor, a rectification circuit for rectifying an AC power source for driving the compressor, and the rectification circuit An inverter that converts the output of the motor into an alternating current, a brushless DC motor that is rotated by the inverter, a position detection circuit that detects the rotational position of the rotor of the brushless DC motor, and each power element of the inverter based on a signal from the position detection circuit A commutation circuit that determines the operation of the motor, a speed detection circuit that detects the rotational speed from the output of the position detection circuit, and a duty setting that adjusts the duty so that the rotational speed from the speed detection circuit matches the set speed Circuit, a reference temperature arbitrarily set in the detection circuit of any one of the internal temperature detection circuit and the outside air temperature detection circuit, and the current temperature If the current temperature is lower than the reference temperature, and the arbitrarily set reference duty is compared with the current duty. If the current duty is equal to or higher than the reference duty, the AC power supply is undervoltage. A refrigerator including a motor drive device, wherein the output of the inverter is stopped when the undervoltage determination circuit determines that there is an undervoltage.   An internal temperature detection circuit provided inside the refrigerator, an outside temperature detection circuit provided outside the refrigerator, a compressor, a rectification circuit for rectifying an AC power source for driving the compressor, and the rectification circuit An inverter that converts the output of the motor into an alternating current, a brushless DC motor that is rotated by the inverter, a position detection circuit that detects the rotational position of the rotor of the brushless DC motor, and each power element of the inverter based on a signal from the position detection circuit A commutation circuit that determines the operation of the motor, a speed detection circuit that detects the rotational speed from the output of the position detection circuit, and a duty setting that adjusts the duty so that the rotational speed from the speed detection circuit matches the set speed A reference temperature and a current temperature arbitrarily set in a detection circuit of the circuit, the internal temperature detection circuit, and the outside temperature detection circuit If the current temperature is equal to or higher than the reference temperature, the reference duty set arbitrarily is compared with the current duty, and if the current duty is less than the reference duty, the AC power supply is overvoltage And an overvoltage determination circuit for determining whether or not the overvoltage determination circuit determines that the overvoltage is overvoltage, and stops the output of the inverter.   An internal temperature detection circuit provided inside the refrigerator, an outside temperature detection circuit provided outside the refrigerator, a compressor, a rectification circuit for rectifying an AC power source for driving the compressor, and the rectification circuit An inverter that converts the output of the motor into an alternating current, a brushless DC motor that is rotated by the inverter, a position detection circuit that detects the rotational position of the rotor of the brushless DC motor, and each power element of the inverter based on a signal from the position detection circuit A commutation circuit that determines the operation of the motor, a speed detection circuit that detects a rotational speed from the output of the position detection circuit, and a detection circuit that is any of the internal temperature detection circuit and the outside air temperature detection circuit. The reference temperature is compared with the current temperature, the current temperature is lower than the reference temperature, and the rotation speed set arbitrarily is compared with the current rotation speed. An undervoltage determination circuit that determines that the AC power supply is undervoltage if the rotation speed of the inverter is equal to or less than a reference rotation speed, and outputs the output of the inverter when the undervoltage determination circuit determines that the undervoltage is undervoltage A refrigerator provided with a motor driving device characterized by stopping.   An internal temperature detection circuit provided inside the refrigerator, an outside temperature detection circuit provided outside the refrigerator, a compressor, a rectification circuit for rectifying an AC power source for driving the compressor, and the rectification circuit An inverter that converts the output of the motor into an alternating current, a brushless DC motor that is rotated by the inverter, a position detection circuit that detects the rotational position of the rotor of the brushless DC motor, and each power element of the inverter based on a signal from the position detection circuit A commutation circuit that determines the operation of the motor, a speed detection circuit that detects a rotational speed from the output of the position detection circuit, and a detection circuit that is any of the internal temperature detection circuit and the outside air temperature detection circuit. The reference temperature is compared with the current temperature, the current temperature is equal to or higher than the reference temperature, and a ratio between the reference rotation speed set arbitrarily and the current rotation speed is compared. And an overvoltage determination circuit that determines that the AC power supply is overvoltage if the current rotation speed is equal to or higher than a reference rotation speed, and stops output of the inverter when the overvoltage determination circuit determines that the overvoltage is overvoltage A refrigerator provided with a motor driving device.   An internal temperature detection circuit provided inside the refrigerator, an outside temperature detection circuit provided outside the refrigerator, a compressor, a rectification circuit for rectifying an AC power source for driving the compressor, and the rectification circuit An inverter that converts the output of the motor into an alternating current, a brushless DC motor that is rotated by the inverter, a position detection circuit that detects the rotational position of the rotor of the brushless DC motor, and each power element of the inverter based on a signal from the position detection circuit A commutation circuit that determines the operation of the motor, a speed detection circuit that detects the rotational speed from the output of the position detection circuit, and a duty setting that adjusts the duty so that the rotational speed from the speed detection circuit matches the set speed If the rotation speed detected by the speed detection circuit does not reach the predetermined rotation speed even if the duty ratio is changed by the circuit and the duty setting circuit, An overlap angle setting circuit for adding / subtracting an overlap angle to the reference temperature, a reference temperature arbitrarily set in any one of the detection circuit of the internal temperature detection circuit and the outside air temperature detection circuit, and the current temperature, If the temperature is below the reference temperature and the reference overlap angle set arbitrarily and the current overlap angle are compared, and the current overlap angle is greater than or equal to the reference overlap angle, the AC power supply is undervoltage And a undervoltage determination circuit for determining that the output voltage of the inverter is stopped when the undervoltage determination circuit determines that the voltage is insufficient.   An internal temperature detection circuit provided inside the refrigerator, an outside temperature detection circuit provided outside the refrigerator, a compressor, a rectification circuit for rectifying an AC power source for driving the compressor, and the rectification circuit An inverter that converts the output of the motor into an alternating current, a brushless DC motor that is rotated by the inverter, a position detection circuit that detects the rotational position of the rotor of the brushless DC motor, and each power element of the inverter based on a signal from the position detection circuit A commutation circuit that determines the operation of the motor, a speed detection circuit that detects the rotational speed from the output of the position detection circuit, and a duty setting that adjusts the duty so that the rotational speed from the speed detection circuit matches the set speed If the rotation speed detected by the speed detection circuit does not reach the predetermined rotation speed even if the duty ratio is changed by the circuit and the duty setting circuit, An overlap angle setting circuit for adding and subtracting the overlap angle to the reference temperature, a reference temperature arbitrarily set in any one of the detection circuit of the internal temperature detection circuit and the outside air temperature detection circuit, and the current temperature, If the temperature is equal to or higher than the reference temperature and the reference overlap angle set arbitrarily is compared with the current overlap angle, and the current overlap angle is less than the reference overlap angle, the AC power supply is overvoltage An overvoltage determination circuit for determining whether there is an overvoltage, and when the overvoltage determination circuit determines that there is an overvoltage, the output of the inverter is stopped.