Refrigerator

Abstract

The invention provides a refrigerator capable of reducing power consumption of a control circuit for controlling a motor of a compressor. The refrigerator includes a compressor, a compressor control circuit that controls the compressor, and a switching circuit that turns on / off supply of power to the compressor control circuit.

Description

Technical Field

[0001] The present invention relates to the technology of refrigerators. Background Art

[0002] A technology for controlling a motor of a compressor of a refrigerator is proposed.

[0003] For example, Japanese Patent Application Laid-Open No. 2002-27777 discloses a method for controlling the torque of a motor. In Japanese Patent Application Laid-Open No. 2002-27777, a method for controlling the torque of a motor is proposed, which is characterized in that: when changing the target rotational speed of the motor from low speed to high speed, the width of the torque compensation amount of the torque pattern is temporarily made narrower than a specified value, and after reaching the target rotational speed and passing a specified time, the torque compensation amount is returned to the specified value. Summary of the Invention

[0004] An object of one aspect of the present invention is to reduce the power consumption of a control circuit for controlling a motor of a compressor.

[0005] According to one aspect of the present invention, there is provided a refrigerator including: a compressor; a compressor control circuit for controlling the compressor; and a switch circuit for turning on / off the power supply to the compressor control circuit.

[0006] As described above, according to one aspect of the present invention, it is possible to reduce the power consumption of a control circuit for controlling a motor of a compressor. Brief Description of the Drawings

[0007] Figure 1 is a block diagram showing the configuration of the refrigerator according to the first embodiment.

[0008] Figure 2 is a circuit configuration diagram of a part related to the compressor control circuit according to the first embodiment.

[0009] Figure 3 is a circuit configuration diagram of a part related to the compressor control circuit according to the second embodiment.

[0010] Figure 4 is a circuit configuration diagram of a part related to the compressor control circuit according to the third embodiment. Detailed Description of the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals are given to the same components. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0012] [First Embodiment] <Overall Structure of Refrigerator 100> First, refer toFigure 1 Describe the overall structure of the refrigerator 100 according to this embodiment.

[0013] The refrigerator 100 according to this embodiment mainly includes a refrigeration cycle 110. The refrigeration cycle 110 mainly includes a compressor 130, a condenser 141, a decompressor 142, an evaporator 143, and a compressor control circuit 135 that drives and controls the motor of the compressor 130. In addition, a fan 150 is provided in the refrigeration cycle 110 to circulate the cold air generated by the condenser 141 inside the refrigerator 100. And the refrigeration cycle 110 includes a main control circuit 120 for controlling each part thereof.

[0014] More specifically, a voltage is applied to the compressor 130 from the commercial power supply 170 via the compressor control circuit 135. The motor of the compressor 130 is driven and controlled by the output frequency of the compressor control circuit 135.

[0015] The compressor control circuit 135 receives a control signal from the main control circuit 120 and drives the motor by applying a voltage with a specified voltage duty and frequency to the motor of the compressor 130.

[0016] The main control circuit 120 includes a CPU (Central Processing Unit) and a memory. More specifically, the CPU executes various processes according to the programs stored in the memory. For example, the CPU of the main control circuit 120 calculates the output frequency to the compressor control circuit 135 based on the difference between the set temperature inside the cabinet input by the user via the in-cabinet temperature setting switch 125 and the detected temperature inside the cabinet input from the in-cabinet temperature sensor 126, and inputs a control signal based on the calculation result to the compressor control circuit 135.

[0017] More specifically, when the difference between the set temperature inside the cabinet and the detected temperature inside the cabinet is large, the main control circuit 120 sets the output frequency high, and increases the driving force of the motor of the compressor 130 via the compressor control circuit 135 to make it approach the set temperature. On the other hand, when the difference between the set temperature inside the cabinet and the detected temperature inside the cabinet is small, the main control circuit 120 sets the output frequency low, and reduces the driving force of the motor of the compressor 130 via the compressor control circuit 135.

[0018] <Structure related to the compressor control circuit 135 for motor control> Next, with reference to Figure 2 Describe the structure for reducing the power consumption of the compressor control circuit 135 according to this embodiment.

[0019] The refrigerator 100 is provided with a power supply circuit 101. The power supply circuit 101 generates electric power supplied to the compressor control circuit 135 and the fan 150. The power supply circuit 101 includes a DC power supply (not shown), a transformer 160, and a switching power supply IC (Integrated Circuit) 121 (power control circuit).

[0020] The DC power supply converts the AC voltage supplied from the commercial power supply 170 into a DC voltage and outputs it to the transformer 160. In addition, the DC power supply may have a boosting function.

[0021] The transformer 160 is an insulated transformer having a primary winding 161, a secondary winding 162, and an auxiliary winding 163. The primary winding 161 is electrically connected to the DC power supply and is applied with a DC voltage. The secondary winding 162 is magnetically coupled to the primary winding 161 via an iron core. The secondary winding 162 is electrically connected to the motor 151 of the fan 150 via the main control circuit 120. In addition, the secondary winding 162 is not electrically connected to the circuit GND of the DC power supply and the primary winding 161. Therefore, the secondary winding 162 is electrically insulated from the DC power supply and the primary winding 161. The auxiliary winding 163 is magnetically coupled to the primary winding 161 via an iron core. The auxiliary winding 163 is electrically connected to the switching power supply IC 121 and the compressor control circuit 135. In addition, the auxiliary winding 163 is electrically connected to the primary winding 161 via the circuit GND of the DC power supply. Therefore, the auxiliary winding 163 is not electrically insulated from the DC power supply and the primary winding 161.

[0022] The switching power supply IC 121 is electrically connected to the primary winding 161 of the transformer 160. The switching power supply IC 121 includes a switching element (e.g., FET (Field Effect Transistor)) electrically connected between one end of the primary winding 161 and the circuit GND. The switching power supply IC 121 controls the current supplied from the DC power supply to the primary winding 161 by driving the switching element to be turned on / off. By turning the switching element on / off, an induced electromotive force is generated in the secondary winding 162 and the auxiliary winding 163. The induced electromotive force generated in the secondary winding 162 is supplied to the main control circuit 120 and the fan 150.

[0023] The main control circuit 120 controls the fan 150. For example, the main control circuit 120 controls the fan 150 in such a way that the rotational speed of the motor 151 of the fan 150 becomes the target rotational speed. In addition, the control target of the main control circuit 120 is not limited to the fan 150, but also includes other units. The rotational speed of the motor of the fan 150 depends on the magnitude of the electric power supplied from the secondary winding 162. The main control circuit 120 sends a control instruction signal to the switching power supply IC 121 in such a way that the rotational speed of the motor of the fan 150 becomes the target rotational speed. In other words, the main control circuit 120 sends a control instruction signal to the switching power supply IC 121 in such a way that the induced electromotive force generated in the secondary winding 162 becomes the target electric power. In order to maintain the electrical insulation between the main control circuit 120 and the switching power supply IC 121, the control instruction signal is transmitted via an optocoupler. In addition, in Figure 2 the figure showing the transmission path of the control instruction signal is omitted. The switching power supply IC 121 controls the switching element based on the control instruction signal from the main control circuit 120, whereby the induced electromotive force generated in the secondary winding 162 becomes the target electric power, that is, the rotational speed of the motor of the fan 150 becomes the target rotational speed. That is, the switching power supply IC 121 performs feedback control on the current flowing through the primary winding 161 so that the electric power supplied to the fan 150 becomes the target electric power.

[0024] The auxiliary winding 163 is electrically connected to the switching power supply IC 121 and the compressor control circuit 135 via a diode. The induced electromotive force generated by the auxiliary winding 163 is supplied to the switching power supply IC 121 and the compressor control circuit 135. The switching power supply IC 121 and the compressor control circuit 135 operate using the electric power supplied from the auxiliary winding 163. In addition, for example, at the start of the switching power supply IC 121 such as immediately after the refrigerator 100 is powered on, the switching element is turned on / off driven using the supply power from a DC power supply different from the auxiliary winding 163. Moreover, after the electric power supplied from the auxiliary winding 163 becomes stable, the switching power supply IC 121 operates using the supply power from the auxiliary winding 163.

[0025] In addition, the refrigerator 100 of the present embodiment includes a switching circuit 136. The switching circuit 136 is electrically connected between the auxiliary winding 163 and the compressor control circuit 135. The switching circuit 136 is configured to turn on / off the power supply from the power supply circuit 101 (auxiliary winding 163) to the compressor control circuit 135. In the present embodiment, the switching circuit 136 is configured to conduct when the input voltage VCC_I, which is the voltage across both ends of the auxiliary winding 163, is equal to or higher than the threshold value Vth. Specifically, the switching circuit 136 includes a switching element SW1 and a turn-on / off circuit 1361.

[0026] One end of the switching element SW1 is electrically connected to the auxiliary winding 163 via a diode, and the other end is electrically connected to the compressor control circuit 135. In the present embodiment, the switching element SW1 is an n-channel MOSFET (Metal Oxide Semiconductor Field Effect Transistor). The drain of the switching element SW1 is electrically connected to the auxiliary winding 163 via a diode, the source is electrically connected to the compressor control circuit 135, and the gate is electrically connected to the on / off circuit 1361. When the switching element SW1 is in the on state, conduction is established between the auxiliary winding 163 and the compressor control circuit 135, and power is supplied from the auxiliary winding 163 to the compressor control circuit 135. When the switching element SW1 is in the off state, non-conduction is established between the auxiliary winding 163 and the compressor control circuit 135, and the power supply from the auxiliary winding 163 to the compressor control circuit 135 is cut off. The on / off of the switching element SW1 is controlled by the on / off circuit 1361.

[0027] The on / off circuit 1361 controls the on / off of the switching element SW1 based on the voltage across the auxiliary winding 163 (input voltage VCC_I). Specifically, when the input voltage VCC_I is equal to or higher than the threshold Vth, the on / off circuit 1361 turns on the switching element SW1. In the present embodiment, the on / off circuit 1361 is a series circuit of a resistor R11 and a resistor R12 electrically connected between the two ends of the auxiliary winding 163. The connection point of the resistors R11 and R12 is electrically connected to the gate of the switching element SW1. Therefore, a voltage obtained by dividing the input voltage VCC_I by the resistors R11 and R12 is applied to the gate of the switching element SW1. When the input voltage VCC_I is equal to or higher than the threshold Vth, the resistance ratio of the resistors R11 and R12 is set such that the voltage value obtained by resistor voltage division based on the resistors R11 and R12 is equal to or higher than the conduction voltage of the switching element SW1. The setting of the threshold Vth will be described later.

[0028] As described above, the auxiliary winding 163 is magnetically coupled to the primary winding 161 together with the secondary winding 162. Therefore, by performing feedback control on the current flowing through the primary winding 161, the power supplied by the switching power supply IC121 to the fan 150 is made to be the target power. Thus, similarly to the induced electromotive force of the secondary winding 162, the induced electromotive force of the auxiliary winding 163 also varies. That is, the voltage across the auxiliary winding 163 (input voltage VCC_I) varies according to the target rotational speed (target power) of the fan 150.

[0029] Here, the refrigeration cycle 110 of the refrigerator 100 of the present embodiment has the following properties.

[0030] (1) As an operation example of the refrigeration cycle 110, when the motor 131 of the compressor 130 is driven, in order to circulate the generated cool air in the box, loads such as the fan 150 also operate simultaneously.

[0031] (2) When the fan 150 is operating, compared with the case where the fan 150 is stopped, the target rotation speed (target power) of the fan 150 becomes higher. Therefore, through the feedback control of the switching power supply IC 121, the voltage across both ends of the auxiliary winding 163 (input voltage VCC_I) also becomes higher.

[0032] Therefore, the above-mentioned threshold voltage Vth is set to a value Vx1 that is lower than the input voltage VCC_I when the fan 150 is operating and higher than the input voltage VCC_I when the fan 150 is stopped (Vx1 > Vth > Vx2).

[0033] In the present embodiment, when the driving of the motor 131 of the compressor 130 starts, first, the main control circuit 120 starts the operation of the fan 150. As a result, the voltage value of the voltage across both ends of the auxiliary winding 163 (input voltage VCC_I) rises from Vx2 (< threshold Vth) to Vx1 (> threshold Vth). When the input voltage VCC_I exceeds the threshold Vth, the switching element SW1 conducts, and power supply to the compressor control circuit 135 starts. The compressor control circuit 135 starts to operate by being supplied with power and starts the control of the compressor 130. In addition, when the operation of the compressor 130 starts, if the fan 150 is already operating, since power has already been supplied to the compressor control circuit 135, the control of the compressor 130 can be started.

[0034] On the other hand, when the compressor 130 and the fan 150 are stopped, the voltage value of the voltage across both ends of the auxiliary winding 163 (input voltage VCC_I) becomes Vx2 (< threshold Vth). Since the input voltage VCC_I is less than the threshold Vth, the switching element SW1 is in an off state, and power is not supplied to the compressor control circuit 135.

[0035] Thus, in the present embodiment, the power supply to the compressor control circuit 135 is turned on / off in conjunction with the operation of the switch circuit 136 and the fan 150. When the compressor 130 is operating, the fan 150 also needs to operate, so the power supply to the compressor control circuit 135 is turned on. On the other hand, when the compressor 130 and the fan 150 are stopped, the power supply to the compressor control circuit 135 is stopped. Thereby, when the compressor 130 is operating, power is supplied to the compressor control circuit 135; when the compressor 130 is stopped, the power supply to the compressor control circuit 135 can be stopped. Therefore, compared with the structure in which power is always supplied to the compressor control circuit 135 regardless of the operating state of the compressor 130, the power consumption of the compressor control circuit 135 can be reduced. As a result, the power consumption of the refrigerator 100 can be reduced.

[0036] [Second Embodiment] As Figure 3 shown, the switch circuit 136 of the above embodiment can be replaced with a switch circuit 236 having a constant voltage output function.

[0037] The switch circuit 236 of the present embodiment is electrically connected between the auxiliary winding 163 and the compressor control circuit 135. The switch circuit 236 is configured to turn on / off the power supply from the power supply circuit 101 (auxiliary winding 163) to the compressor control circuit 135. In the present embodiment, the switch circuit 136 is configured to apply a certain output voltage to the compressor control circuit 135 when the input voltage VCC_I, which is the voltage across both ends of the auxiliary winding 163, is equal to or higher than the threshold value Vth. Specifically, the switch circuit 236 includes a turn-on / off circuit 2361 and a constant voltage circuit 2362.

[0038] The turn-on / off circuit 2361 turns on the constant voltage circuit 2362 when the input voltage VCC_I is equal to or higher than the threshold value Vth.

[0039] The input terminal of the constant voltage circuit 2362 is electrically connected to the auxiliary winding 163 via a diode, and the output terminal is electrically connected to the compressor control circuit 135. The constant voltage circuit 2362 is configured to output a voltage from the output terminal when in the conducting state.

[0040] Therefore, when the main control circuit 120 starts the operation of the fan 150, the voltage value of the voltage across both ends of the auxiliary winding 163 (input voltage VCC_I) rises from Vx2 (< threshold value Vth) to Vx1 (> threshold value Vth). Since the input voltage VCC_I exceeds the threshold value Vth, the constant voltage circuit 2362 operates and starts the power supply to the compressor control circuit 135.

[0041] In addition, the constant voltage circuit 2362 is configured such that the output voltage output from the output terminal becomes a specified voltage value Vx3. More specifically, when the voltage value of the input voltage VCC_I input to the input terminal is equal to or higher than the voltage value Vx3, the constant voltage circuit 2362 steps down the input voltage VCC_I to the voltage value Vx3 and outputs it from the output terminal. The voltage value Vx3 is a value within the allowable range of the input voltage of the compressor control circuit 135.

[0042] Accordingly, even when the voltage value of the voltage across the auxiliary winding 163 (input voltage VCC_I) varies to a value higher than the upper limit value of the input voltage of the compressor control circuit 135, it is possible to suppress the application of an overvoltage exceeding the upper limit value of the input voltage to the compressor control circuit 135.

[0043] [Third Embodiment] As Figure 4 shown, the switch circuits 136 and 236 of the above-described embodiment may be replaced with a switch circuit 336 that is switched between on and off according to a signal from the main control circuit 120.

[0044] The switch circuit 336 of the present embodiment is electrically connected between the auxiliary winding 163 and the compressor control circuit 135. The switch circuit 336 is configured to turn on and off the power supply from the power supply circuit 101 (auxiliary winding 163) to the compressor control circuit 135. In the present embodiment, the switch circuit 336 is controlled to be turned on and off by the main control circuit 120. The switch circuit 336 includes a switching element SW2 such as an n-channel MOSFET, for example. The switching element SW2 is turned on and off based on a control signal from the main control circuit 120. In addition, the switch circuit 336 may include a drive circuit that turns on and off the switching element SW2 based on a control signal from the main control circuit 120. In order to maintain electrical insulation between the main control circuit 120 and the switch circuit 336, the control signal is transmitted via an optocoupler.

[0045] In the present embodiment, the main control circuit 120 controls the on and off of the switch circuit 336. Therefore, when stopping the compressor 130, the main control circuit 120 can turn off the switch circuit 336 and stop the power supply to the compressor control circuit 135.

[0046] In addition, the main control circuit 120 can independently control the control of the fan 150 and the power supply to the compressor control circuit 135. Therefore, even when stopping the compressor 130 and operating the fan 150, it is possible to turn off the switch circuit 336 and stop the power supply to the compressor control circuit 135.

[0047] <Summary> In the above-described embodiment, a refrigerator is provided, which includes: a compressor; a compressor control circuit for controlling the compressor; and a switch circuit for turning on / off the power supply to the compressor control circuit.

[0048] Preferably, the refrigerator further includes: a fan; and a power supply circuit for generating the power supplied to the compressor control circuit and the fan. The power supply circuit has a transformer and a power supply control circuit. The transformer includes a primary winding, a secondary winding magnetically coupled to the primary winding and electrically connected to the fan, and an auxiliary winding magnetically coupled to the primary winding; the power supply control circuit controls the current flowing through the primary winding. The switch circuit is electrically connected between the auxiliary winding and the compressor control circuit.

[0049] Preferably, the power supply control circuit performs feedback control on the current flowing through the primary winding so that the power supplied to the fan becomes a target power.

[0050] Preferably, the switch circuit is configured to conduct when the input voltage is above a threshold value.

[0051] Preferably, the switch circuit includes a constant voltage circuit that applies a constant output voltage to the compressor control circuit when the input voltage is above the threshold value.

[0052] Preferably, the refrigerator further includes a main control circuit for controlling the fan. The main control circuit controls the on / off of the switch circuit.

[0053] The embodiments disclosed herein should be considered illustrative in all aspects and not restrictive. The scope of the present invention is not represented by the above description, but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

Claims

1. A refrigerator, characterized in that, Comprising: A compressor; A compressor control circuit that controls the compressor; and A switch circuit that turns on / off the supply of power to the compressor control circuit.

2. The refrigerator according to claim 1, characterized in that, Further comprising: A fan; A power supply circuit that generates power supplied to the compressor control circuit and the fan, The power supply circuit has: A transformer including a primary winding, a secondary winding magnetically coupled to the primary winding and electrically connected to the fan, and an auxiliary winding magnetically coupled to the primary winding; A power supply control circuit that controls the current flowing through the primary winding, The switch circuit is electrically connected between the auxiliary winding and the compressor control circuit.

3. The refrigerator according to claim 2, wherein, The power supply control circuit performs feedback control on the current flowing through the primary winding so that the power supplied to the fan becomes a target power.

4. The refrigerator according to any one of claims 1 to 3, characterized in that, The switch circuit is configured to turn on when the input voltage is equal to or higher than a threshold value.

5. The refrigerator according to any one of claims 1 to 3, characterized in that, The switch circuit includes a constant voltage circuit that applies a constant output voltage to the compressor control circuit when the input voltage is equal to or higher than the threshold value.

6. The refrigerator according to claim 2 or 3, characterized in that, Further comprising a main control circuit that controls the fan, and the main control circuit controls the turning on / off of the switch circuit.

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