WO2017212584A1

WO2017212584A1 - Compressor drive device

Info

Publication number: WO2017212584A1
Application number: PCT/JP2016/067102
Authority: WO
Inventors: 崇仁大西
Original assignee: 三菱電機株式会社
Priority date: 2016-06-08
Filing date: 2016-06-08
Publication date: 2017-12-14

Abstract

The compressor drive device (14) comprises: a compressor (9); a rectification unit (5) for rectifying an alternating-current voltage into a direct-current bus voltage; an inverter device (8) for outputting a voltage command value, which is based on the direct-current bus voltage and a constraint energization output command value, to the compressor (9) while the compressor (9) is in a stopped state; a control unit (11) for outputting the constraint energization output command value, which is determined on the basis of the direct-current bus voltage, to the inverter device (8) while the compressor (9) is in a stopped state in order to preheat the compressor (9); and an outside air temperature sensor (12) for detecting the outside air temperature. The control unit (11) corrects the constraint energization output command value on the basis of the outside air temperature.

Description

Compressor drive unit

The present invention relates to a compressor driving device that performs preheating control when the compressor is stopped.

In the conventional preheating control method, the voltage value of the DC bus voltage supplied to the three-phase inverter device is detected, and preheating control is performed so that the output power value from the inverter device to the compressor is constant regardless of the received voltage. (For example, refer to Patent Document 1).

International Publication No. 2012/088601

In the above-mentioned conventional technology, it is possible to correct fluctuations in the received voltage, but depending on the use environment, fluctuations in the outside air temperature are large, and optimal control may not be achieved. In particular, heating is insufficient at a low outside air temperature, and it is necessary to continue restraint energization control for a long time. In addition, there is a possibility that the transition to the operation mode is delayed.

The present invention has been made in view of the above, and an object of the present invention is to obtain a compressor driving device capable of accelerating the heating of the compressor and the refrigerant in an environment where the outside air temperature is low.

In order to solve the above-described problems and achieve the object, the present invention provides a compressor, a rectifier that rectifies an AC voltage and converts it into a DC bus voltage, and a DC bus when the compressor is stopped. An inverter device that outputs a voltage command value based on the voltage and the restricted energization output command value to the compressor, and a DC bus voltage determined to preheat the compressor when the compressor is stopped The control part which outputs a restraint electricity supply output command value to an inverter apparatus, and the external temperature sensor which detects external temperature are provided. The control unit corrects the restrained energization output command value based on the outside air temperature.

The compressor driving device according to the present invention has an effect that heating of the compressor and the refrigerant can be accelerated under an environment where the outside air temperature is low.

The figure which shows the structure of the compressor drive device concerning Embodiment 1 of this invention. The figure which shows the relationship between the external temperature in Embodiment 1, and the temperature of a hermetic compressor and a heat exchanger FIG. 3 is a flowchart for explaining a method for determining whether or not restraint energization is required according to the first embodiment; The figure which shows the relationship between direct-current bus voltage value Vdc and voltage command value when restraint energization output command value Vout is constant. The figure which shows restraint energization output command value Vout correct | amended based on DC bus voltage value Vdc in Embodiment 1. The figure which shows an example of the correction method of the restricted energization output command value Vout depending on the outside temperature in Embodiment 1. The figure which shows a mode that the upper limit was provided in the correct | amended restricted energization output command value Vout in Embodiment 1. FIG. The figure which shows the example in the case of comprising the control part in Embodiment 1 with exclusive hardware. The figure which shows the hardware constitutions in the case of implement | achieving the control part in Embodiment 1 with a computer

Hereinafter, a compressor driving device according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration of a compressor driving device 14 according to the first embodiment of the present invention. The compressor driving device 14 is an outdoor unit of an air conditioner and is connected to a commercial AC power source 1 that supplies AC power. The compressor driving device 14 is connected to the commercial AC power source 1 and has a filter circuit 2 for noise reduction, an element 3 for limiting inrush current at startup, and an ON state during steady driving and a current path. A relay 4, a diode bridge 5 that is a rectifying unit that rectifies an AC voltage and converts it into a DC bus voltage, and a converter circuit 6 for the purpose of power factor improvement.

The compressor driving device 14 is a hermetically sealed compressor 7a that smoothes the converted DC voltage, a bus voltage detector 7b that detects the DC bus voltage charged in the capacitor 7a, and a compressor that houses an electric motor therein. Control the pre-heat control by controlling the compressor 9, the inverter device 8 for driving the hermetic compressor 9, the overcurrent detector 10 for detecting the overcurrent of the inverter device 8, the relay 4 and the inverter device 8. A control unit 11 for determining necessity, an outside air temperature sensor 12 for detecting the outside air temperature, and a compressor temperature which is a temperature of the hermetic compressor 9 are attached to the outline of the hermetic compressor 9 for the purpose of detecting the compressor temperature. And a compressor temperature sensor 13.

When the inverter device 8 energizes the closed hermetic compressor 9 that is stopped, the inverter device 8 supplies a voltage command value to the hermetic compressor 9 based on the DC bus voltage and the constrained energization output command value Vout from the control unit 11. Is output as power. The controller 11 uses the temperature data acquired from the outside air temperature sensor 12 at a predetermined timing such as every minute, for example, several minutes after the temperature data accumulated several minutes ago and the current temperature data, It is possible to estimate the future outside air temperature after 30 minutes. For example, it is possible to estimate that the outside air temperature becomes higher than the present time in the time when the time is shifted to the noon time zone from about 8 am in fine weather.

FIG. 2 is a diagram showing the relationship between the outside air temperature and the temperatures of the hermetic compressor 9 and the heat exchanger in the first embodiment. Since the heat capacity of the hermetic compressor 9 is larger than that of other devices such as a heat exchanger in the compressor driving device 14, when the outside air temperature becomes higher than the present time, the temperature rise rate of the hermetic compressor 9 is different from that of other devices. Slower than that. As a result, the hermetic compressor 9 is kept in a low temperature state. Since the refrigerant moves to a lower temperature, if the temperature of the hermetic compressor 9 is relatively lower than that of a heat exchanger or the like, the refrigerant is likely to accumulate in the hermetic compressor 9. This is also said that the refrigerant is likely to sleep in the hermetic compressor 9. In addition, as shown in FIG. 2, even when the outside air temperature is low, for example, −10 ° C. or lower, the refrigerant easily moves to the compressor having a lower temperature.

When the inverter device 8 tries to start up the hermetic compressor 9 in a state where the refrigerant is accumulated in the hermetic compressor 9, the starting torque of the hermetic compressor 9 is larger than normal, so the inverter device The output current from 8 will increase. Generation of an output current exceeding a predetermined current value is detected by the overcurrent detector 10, and an overcurrent abnormality is notified from the overcurrent detector 10 to the inverter device 8 and the control unit 11, so that protection is possible. However, due to this notification, the hermetic compressor 9 stops due to the occurrence of an abnormality at startup. In order to avoid such a phenomenon due to the stagnation of the refrigerant, after the operation of the hermetic compressor 9 is stopped, the control unit 11 performs control for preheating the hermetic compressor 9 by restraint energization.

FIG. 3 is a flowchart illustrating a method for determining whether or not restraint energization is required according to the first embodiment. The flowchart of FIG. 3 is implemented by the control unit 11.

When the hermetic compressor 9 is stopped (step S101), the process proceeds to step S102 and subsequent determinations. It is necessary to determine whether or not the energization of the hermetic compressor 9 is required only when the operation is stopped.

After the operation of the hermetic compressor 9 is stopped (Step S101), the control unit 11 determines whether or not the energization of the hermetic compressor 9 is necessary (Step S102). That is, the control unit 11 needs to preheat the hermetic compressor 9 based on the outside air temperature detected by the outside air temperature sensor 12 and the temperature of the hermetic compressor 9 detected by the compressor temperature sensor 13. Make a decision of no.

Specifically, in the case where “(condition 1): the outside air temperature detected by the outside air temperature sensor 12 is equal to or lower than the predetermined temperature A ° C.”, the energization of the hermetic compressor 9 is required (step S102). : Yes) and the control unit 11 determines. The temperature A ° C. is, for example, −10 ° C. As described above, even when the outside air temperature is low, the refrigerant easily moves to the compressor having a lower temperature.

Further, when “(Condition 2): the compressor temperature detected by the compressor temperature sensor 13 is a predetermined temperature B ° C. or less and the change amount of the outside air temperature is a predetermined value ΔC or more” is satisfied, The control unit 11 determines that restraint energization of the hermetic compressor 9 is necessary (step S102: Yes). The temperature B ° C. is, for example, 70 ° C. The amount of change in the outside air temperature is, for example, a temperature difference obtained by subtracting the outside air temperature five minutes ago from the current outside air temperature detected by the outside air temperature sensor 12. ΔC is, for example, 0 ° C. When the compressor temperature is equal to or lower than the temperature B ° C. and the amount of change in the outside air temperature is equal to or greater than the value ΔC, it is in an environment where the outside air temperature rises. As described above, the hermetic compressor 9 is in a low temperature state. Therefore, the controller 11 determines that the energization of the hermetic compressor 9 needs to be restricted (step S102: Yes).

When neither of the above conditions (condition 1) and (condition 2) is satisfied, the controller 11 determines that the energization of the hermetic compressor 9 is not necessary (step S102: No). For example, when (Condition 1) is not satisfied and the compressor temperature detected by the compressor temperature sensor 13 is higher than the temperature B ° C., (Condition 2) is not satisfied. In this case, since it is considered that there is no temperature difference between the compressor temperature and the temperature of other devices, it is not necessary to energize the hermetic compressor 9 (step S102: No).

In step S <b> 102, the reference for determining whether the control unit 11 needs to energize the hermetic compressor 9 is not limited to the above (Condition 1) and (Condition 2). It doesn't matter.

In step S102, when the control unit 11 determines that the energization of the hermetic compressor 9 is not required (step S102: No), the compressor driving device 14 remains in the operation standby state, and the control unit 11 It is determined whether or not a predetermined first waiting time has elapsed (step S107). When it is determined that the first standby time has not elapsed (step S107: No), the control unit 11 returns to step S107. When it is determined that the first standby time has elapsed (step S107: Yes), the control unit 11 returns to step S102. Return to determine whether restraint energization is necessary.

If it is determined that the energization of the hermetic compressor 9 is necessary (step S102: Yes), the control unit 11 first determines whether or not the current outside air temperature detected by the outside air temperature sensor 12 is equal to or lower than X ° C. Is determined (step S103). X ° C. is a predetermined temperature. When the control unit 11 determines that the current outside air temperature is higher than X ° C. (step S103: No), the process proceeds to step S106 because it is necessary to suppress the output in order to avoid excessive preheating to the hermetic compressor 9. When the control unit 11 determines that the current outside air temperature is equal to or lower than X ° C. (step S103: Yes), the process proceeds to step S104.

In step S104, the control unit 11 determines whether or not the compressor temperature detected by the compressor temperature sensor 13 is equal to or lower than Y ° C. (step S104). Y ° C. is a predetermined temperature. When the control unit 11 determines that the compressor temperature is higher than Y ° C. (step S104: No), the voltage command value for restraint energization cannot be increased to protect the temperature of the hermetic compressor 9, and therefore step S106. Proceed to

In step S106, the control unit 11 executes restraint energization with no outside air temperature correction on the hermetic compressor 9. Hereinafter, restraint energization without external temperature correction will be described.

The control unit 11 calculates a restricted energization output command value Vout to be output to the inverter device 8 based on the DC bus voltage value Vdc detected by the bus voltage detector 7b. The voltage command value that is the output from the inverter device 8 to the hermetic compressor 9 is determined based on the DC bus voltage value Vdc and the restrained energization output command value Vout. During the shutdown of the hermetic compressor 9, the converter circuit 6, which is a booster circuit, is not operating, so the DC bus voltage greatly depends on fluctuations in the received voltage supplied from the commercial AC voltage 1. Therefore, in order to correct the change in the voltage command value due to this fluctuation, the control unit 11 calculates the restricted energization output command value Vout based on the DC bus voltage value Vdc.

FIG. 4 is a diagram showing the relationship between the DC bus voltage value Vdc and the voltage command value when the restrained energization output command value Vout is constant. When the restricted energization output command value Vout is constant, the voltage command value that is the output from the inverter device 8 to the hermetic compressor 9 has a higher DC bus voltage value Vdc as the power reception voltage increases as shown in FIG. It grows as it becomes.

Therefore, in order to make the voltage command value output from the inverter device 8 constant, the restrained energization output command value Vout output to the inverter device 8 is set to the following based on the DC bus voltage value Vdc detected by the bus voltage detector 7b. It correct | amends like Numerical formula (1) of these.
Vout = a × Vdc + b (1)
Here, a and b are correction coefficients.

FIG. 5 is a diagram showing the restricted energization output command value Vout corrected based on the DC bus voltage value Vdc in the first embodiment. FIG. 5 shows a state in which the correction coefficient a is a negative value in Equation (1), and the restrained energization output command value Vout decreases as the DC bus voltage value Vdc increases. As shown in FIG. 5, the relationship between the DC bus voltage value Vdc and the voltage command value shown in FIG. 4 can be compensated by correcting the restricted energization output command value Vout based on the DC bus voltage value Vdc. . Based on DC bus voltage value Vdc, control unit 11 determines a restricted energization output command value Vout in accordance with Equation (1). When the controller 11 outputs the determined restricted energization output command value Vout to the inverter device 8, restricted energization without external temperature correction is performed on the hermetic compressor 9 (step S106). As a result, the voltage command value output from the inverter device 8 to the hermetic compressor 9 can be controlled to a constant value regardless of fluctuations in the received voltage supplied from the commercial AC power supply 1.

Equation (1) and FIG. 5 show an example of a method of correcting the constrained energization output command value Vout when the DC bus voltage value Vdc varies, but the DC bus voltage Vdc and voltage command shown in FIG. It changes according to the relationship with the value, and is not necessarily limited to the above example.

In step S104, when the control unit 11 determines that the compressor temperature is equal to or lower than Y ° C. (step S104: Yes), restraint energization with outside air temperature correction is executed (step S105). The outside air temperature correction is intended to further correct the restrained energization output command value Vout when the outside air temperature is low. Hereinafter, restraint energization with outside air temperature correction will be described.

In step S105, based on the outside air temperature detected by the outside air temperature sensor 12, the value of the restricted energization output command value Vout is increased by correcting the mathematical formula (1) used in step S106, so that It becomes possible to carry out the optimum restraint energization corresponding to the fluctuation of the outside air temperature. FIG. 6 is a diagram illustrating an example of a method for correcting the restricted energization output command value Vout depending on the outside air temperature in the first embodiment. An example of a method for correcting such a restricted energization output command value Vout depending on the detected value Ta of the outside air temperature is shown in the following formula (2). Equation (2) is an example of correction depending on the detected value Ta of the outside air temperature, and the correction depending on the outside air temperature is not limited to such correction.
Vout = a × Vdc + b + Ta × c (2)
Here, c is a correction coefficient.

If the correction coefficient c is set to a negative value in Equation (2), the correction shown in FIG. 6 can be realized. Since the correction based on the outside air temperature as described above is the addition of the offset value to the restricted energization output command value Vout, it is not affected by the DC bus voltage. Further, in order to regulate the output to the hermetic compressor 9, a conditional expression such as the following expression (3) is provided so that the restricted energization output command value Vout does not exceed the upper limit value Vout (max). Also good.

If a × Vdc + b + Ta × c> Vout (max),
Vout = Vout (max) (3)

FIG. 7 is a diagram showing a state in which an upper limit value is provided for the corrected energization output command value Vout corrected in the first embodiment. FIG. 7 shows a state in which an upper limit value is provided to the restricted energization output command value Vout corrected based on the DC bus voltage value Vdc according to the conditional expression (3). FIG. 7 shows, from bottom to top, a graph of the restricted energization output command value Vout corresponding to when the detected value Ta of the outside air temperature is high, normal, and extremely low.

In addition, when the detected value Ta> D ° C. of the outside air temperature is satisfied, the correction coefficient c in Expression (2) may be set to zero. Here, D ° C is a predetermined temperature threshold. As a result, when the outside air temperature is high and correction based on the outside air temperature is unnecessary, it is possible not to perform the correction based on the outside air temperature.

When the control unit 11 outputs the restricted energization output command value Vout determined as described above to the inverter device 8, the energization with outside air temperature correction is performed on the hermetic compressor 9 (step). S105).

After steps S105 and S106, the control unit 11 determines whether or not a predetermined second standby time has elapsed (step S108). When it is determined that the second standby time has not elapsed (step S108: No), the control unit 11 returns to step S108. When it is determined that the second standby time has elapsed (step S108: Yes), the control unit 11 returns to step S102. Return to determine whether restraint energization is necessary. As a result, when the restraint energization in steps S105 and S106 is executed for the second waiting time, the necessity of restraint energization is again determined.

According to the compressor driving device 14 according to the first embodiment, it is possible to increase the amount of preheating to the hermetic compressor 9 in an environment where the outside air temperature is low, and to perform preheating control more suitable for the environment. Become. That is, it becomes possible to accelerate the heating to the hermetic compressor 9 and the refrigerant. As a result, it is possible to reduce the time required to raise the temperature of the hermetic compressor 9 to the target temperature at the start of sleep.

FIG. 8 is a diagram illustrating an example in which the control unit 11 according to the first embodiment is configured with dedicated hardware. In this case, the control unit 11 includes a processing circuit 50 that is dedicated hardware as shown in FIG. The processing circuit 50 corresponds to a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. Further, each of the plurality of functions of the control unit 11 may be realized by a plurality of separate processing circuits 50.

FIG. 9 is a diagram illustrating a hardware configuration when the control unit 11 according to the first embodiment is realized by a computer. In this case, the control unit 11 is realized by a CPU (Central Processing Unit) 51 and a memory 52 as shown in FIG. 9 provided in the compressor driving device 14. That is, the function of the control unit 11 is realized by software, firmware, or a combination of software and firmware. Software or firmware is described as a program and stored in the memory 52. The CPU 51 implements the function of the control unit 11 by reading and executing the program stored in the memory 52. That is, the compressor drive device 14 stores a program that results in the step of performing the operation of FIG. 3 by the control unit 11 when the function of the control unit 11 is executed by the computer. The memory 52 is provided. These programs can be said to cause a computer to execute the procedure or method of the control unit 11 related to the control of the compressor driving device 14.

Here, the memory 52 is a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Nonvolatile Memory, or an EEPROM (Electrically Erasable Memory) A semiconductor memory, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, and a DVD (Digital Versatile Disk) are applicable.

Further, a part of the functions of the control unit 11 related to the control of the compressor driving device 14 may be realized by dedicated hardware, and a part may be realized by software or firmware. Thus, the control part 11 concerning control of the compressor drive device 14 can implement | achieve each function mentioned above with hardware, software, firmware, or these combination.

The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

1 commercial AC power supply, 2 filter circuit, 3 elements, 4 relay, 5 diode bridge, 6 converter circuit, 7a capacitor, 7b bus voltage detector, 8 inverter device, 9 hermetic compressor, 10 overcurrent detector, 11 control Part, 12 outside air temperature sensor, 13 compressor temperature sensor, 14 compressor drive device, 50 processing circuit, 51 CPU, 52 memory.

Claims

A compressor,
A rectifier that rectifies an AC voltage and converts it to a DC bus voltage;
When the compressor is stopped, an inverter device that outputs a voltage command value based on the DC bus voltage and a constraint energization output command value to the compressor;
A controller that outputs the restrained energization output command value determined based on the DC bus voltage to the inverter device in order to preheat the compressor when the compressor is stopped;
An outside temperature sensor for detecting the outside temperature;
With
The said control part correct | amends the said restraining electricity supply output command value based on the said external temperature. The compressor drive device characterized by the above-mentioned.
The compressor driving apparatus according to claim 1, wherein the control unit corrects the constraint energization output command value by adding an offset value based on the outside air temperature.
The compressor driving apparatus according to claim 1, wherein the control unit determines whether the preheating is necessary based on the outside air temperature.
A compressor temperature sensor for detecting the temperature of the compressor;
The compressor driving device according to claim 3, wherein the control unit determines whether or not the preheating is necessary based on the outside air temperature and the temperature of the compressor.