Air conditioning device

• US 5,793,623 A
• Filed: 06/29/1995
• Issued: 08/11/1998
• Est. Priority Date: 07/01/1994
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Kawashima, Nobuhiro, Ikebou, Yasuhiro, Takii, Hisayoshi
• Primary Examiner(s): Nguyen, Matthew V.
• Assistant Examiner(s): JARDIEU, DEREK
• Application Number:
  US08/496,285
• Time in Patent Office: 1,139 Days
• Field of Search: 363/36, 363/37, 363/56, 363/45, 363/46, 363/98, 363/34, 363/40
• US Class Current: 363/56.05
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02M 5/458 using semiconductor devices only
• CPC Class Codes: H02M 7/53873 with digital control
• CPC Class Codes: H02P 23/26 Power factor control [PFC]
• CPC Class Codes: H02P 27/08 with pulse width modulation
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

An air conditioning device is arranged such that an output voltage from a commercial power source is converted into a direct current by a rectifying circuit and a smoothing condenser. Thereafter, it is further converted into an AC voltage having a variable frequency by an inverter under the control of a microcomputer, thereby supplying it to a power compressor. Between the rectifying circuit and the smoothing condenser, an active filter is provided for shaping an input current to be an approximate sine wave almost in phase with an input voltage by switching a power transistor. The switching control section and the microcomputer for controlling the switching are activated independently by separately provided power sources. The switching control section supplies a high level signal when the active filter is a normal condition, and supplies a low level signal when the active filter is abnormal. A circuit which generates a low level signal when the power supply to the switching control section is shut off, is provided. This enables the microcomputer to determine the occurrence of an abnormality in the active filter or the switching control section even when the power supply is shut off.

Claims

1. An air conditioning device, comprising:

rectification means for rectifying an AC voltage outputted from an AC power source;

smoothing means for smoothing the rectified AC voltage prior to conversion into a DC voltage;

DC voltage-AC voltage conversion means for converting, by chopping, the DC voltage from said smoothing means into an AC voltage, whose voltage and frequency vary, to be applied to a power compressor;

control means for controlling an output of said DC voltage-AC voltage conversion means according to a load state of said power compressor;

an active filters, formed between said rectification means and said smoothing means, for shaping an input current to be an approximate sine wave almost in phase with an input voltage;

active filter control means for controlling said active filter in response to an instruction from said control means, said active filter control means being actuated by a power source separately provided from a power source for said control means; and

abnormality detection means for detecting an abnormality or a shut-off of at least one of said active filter and said active filter control means and detecting a shut-off of power to be supplied to said active filter control means as an abnormality, wherein detection of an abnormality is linked to control of an operation of the DC voltage-AC voltage conversion means.

2. The air condition device as set forth in claim 1, wherein:

said control means shuts off said DC voltage-AC voltage conversion means upon receiving a detecting signal from said abnormality detection means indicating detection of an abnormality.

3. The air conditioning device as set forth in claim 1, wherein:

said control means shuts off said active filter upon the abnormality detection means detecting an abnormality or stoppage of said power compressor.

4. The air conditioning device as set forth in claim 1 wherein:

said control means controls an output from said DC voltage-AC voltage conversion means so as to raise an effective output voltage from said DC voltage-AC voltage conversion means upon receiving a detecting signal from said abnormality detection means indicating detection of an abnormality.

5. An air conditioning device, comprising:

rectification means for rectifying an AC voltage outputted from an AC power source;

smoothing means for smoothing the rectified AC voltage prior to conversion into a DC voltage;

DC voltage-AC voltage conversion means for converting, by chopping, the DC voltage from said smoothing means into an AC voltage, whose voltage and frequency vary;

an active filter, formed between said rectification means and said smoothing means, for shaping an input current to be an approximate sine wave almost in phase with an input voltage;

overvoltage detecting means for detecting if the output voltage from said active filter is an overvoltage of not less than a predetermined threshold overvoltage value; and

overvoltage preventing means for shutting off said active filter upon detecting that an output voltage from said active filter is an overvoltage, while ignoring a result of detection of overvoltage of said overvoltage detection means for a predetermined time immediately after a turn-on time and a turn-off time of said DC voltage-AC voltage conversion means or for a predetermined time immediately after a turn-on time of said active filter.

6. An air conditioning device, comprising:

rectification means for rectifying an AC voltage outputted from an AC power source;

smoothing means for smoothing the rectified AC voltage prior to conversion into a DC voltage;

DC voltage-Ac voltage conversion means for converting, by chopping, the DC voltage from said smoothing means into an AC voltage, whose voltage and frequency vary, to be applied to a power compressor;

an active filters, formed between said rectification means and said smoothing means, for shaping an input current to be an approximate since wave almost in phase with an input voltage; and

overvoltage preventing means for shutting off said active filter upon detecting that an output voltage from said active filter is an overvoltage in excess of a predetermined threshold, and for raising the predetermined threshold for a predetermined time when starting up said active filter or said power compressor.

7. The air conditioning device as set forth in claim 6, further comprising:

threshold determination means for altering the predetermined threshold according to an output voltage so as to maintain a constant difference between the output voltage from said active filter and the predetermined threshold.

8. An air conditioning device, comprising:

rectification means for rectifying an AC voltage outputted from an AC power source;

smoothing means for smoothing the rectified AC voltage prior to conversion into a DC voltage;

DC voltage-AC voltage conversion means for converting, by chopping, the DC voltage from said smoothing means into an AC voltage, whose voltage and frequency vary, to be applied to a power compressor;

an active filter, formed between said rectification means and said smoothing means, for shaping an input current to be an approximate sine wave almost in phase with an input voltage;

overvoltage preventing means for stopping said active filter upon detecting that the output voltage from said active filter is an overvoltage of not less than a predetermined threshold value;

active filter control means for controlling the active filter, and including output voltage detection means for detecting an output voltage from said active filter, and voltage difference detection means for outputting a difference between the output detected by said output voltage detection means and a reference voltage, wherein said active filter control means includes waveform rounding means for rounding off the output from said voltage difference detection means, said active filter control means controlling said active filter so as to maintain an output voltage therefrom when said power compressor starts activating, not to exceed the predetermined threshold value.

9. The air conditioning device as set forth in claim 8, wherein:

said waveform rounding means is a low pass filter formed between said output voltage detection means and said voltage difference detection means.

10. The air conditioning device as set forth in claim 8, wherein:

said voltage difference detection means is an error amplifier, and said waveform rounding means is time constant alteration means for making a time constant of said error amplifier larger for a predetermined time when starting up said active filter or said power compressor.

11. An air conditioning device comprising:

rectification means for rectifying the rectified AC voltage prior to conversion into a DC voltage;

DC voltage-AC voltage conversion means for converting, by chopping, the DC voltage from said smoothing means into an AC voltage, whose voltage and frequency vary;

control means for controlling an output frequency from said DC voltage-AC voltage conversion means according to a load state of said power compressor and for lowering a changing rate of an operating frequency of said power compressor for a predetermined time immediately after starting an alteration and immediately before completing the alteration of the operating frequency; and

an active filters, formed between said rectification means and said smoothing means, for shaping an input current to be an approximate sine wave almost in phase with an input voltage.

12. An air conditioning device, comprising:

rectification means for rectifying an AC voltage outputted from an AC power source;

smoothing means for smoothing the rectified AC voltage prior to conversion into a DC voltage;

DC voltage-AC voltage conversion means for converting, by chopping, the DC voltage from said smoothing means into an AC voltage, whose voltage and frequency vary, to be applied to a power compressor;

an active filter, formed between said rectification means and said smoothing means, for shaping an input current to be an approximate sine wave almost in phase with an input voltage;

load detection means for always detecting a load state of said power compressor during operation;

output voltage setting means for increasing an output voltage of said active filter based upon a difference between a load state detected by said load state detection means when said power compressor is driven under an increased load and when said power compressor is driven under a load prestored when stably activating said power compressor so as to maintain the number of rotations of the power compressor constant; and

active filter control means for controlling said active filter based on the increased output voltage.

13. The air conditioning device as set forth in claim 12, wherein:

said load state detection means detects a slip of said power compressor as a load state.

14. The air conditioning device as set forth in claim 12, wherein:

said load state detection means detects a load current flowing through said power compressor as a load state.

15. An air conditioning device, comprising:

rectification means for rectifying an AC voltage outputted from an AC power source;

smoothing means for smoothing the rectified AC voltage prior to conversion into a DC voltage;

DC voltage-AC voltage conversion means for converting, by chopping, the DC voltage from said smoothing means into an AC voltage, whose voltage and frequency vary, to a power compressor;

an active filters, formed between said rectification means and said smoothing means, for shaping an input current to be an approximate sine wave almost in phase with an input voltage, a ground potential thereof matching that of said DC voltage-AC voltage conversion means;

active filter control means for controlling said active filter; and

power supply means for supplying a driving power to said DC voltage-AC voltage conversion means through a power source output terminal, said power supply means also supplying a driving power to said active filter control means through another power source output terminal.

16. An air conditioning device, comprising:

rectification means for rectifying an AC voltage outputted from an AC power source;

smoothing means for smoothing the rectified AC voltage prior to conversion into a DC voltage;

DC voltage-AC voltage conversion means for converting, by chopping, the DC voltage from said smoothing means into an AC voltage, whose voltage and frequency vary, to be applied to a power compressor;

an active filter, formed between said rectification means and said smoothing means, said active filter including a choke coil whose inductance decreases as current flowing into the coil increases, said active filter shaping an input current to be an approximate sine wave almost in phase with an input voltage by adjusting a flow of current into said smoothing means through said choke coil by switching a switching element; and

switching control means for varying a switching frequency of said switching element, according to at least one of the current flowing through said choke coil and an output frequency of said AC power source, such that the switching frequency is increased as the current flowing into the coil increases.

17. An air conditioning device, comprising:

rectification means for rectifying an AC voltage outputted from an AC power source;

smoothing means for smoothing the rectified AC voltage prior to conversion into a DC voltage;

DC voltage-AC voltage conversion means for converting, by chopping, the DC voltage from said smoothing means into an AC voltages, whose voltage and frequency vary, to be applied to a power compressor;

an active filters, formed between said rectification means and said smoothing means, for shaping an input current to be an approximate sine wave almost in phase with an input voltage;

active filter control means for controlling said active filter;

overvoltage detection means for detecting that an output voltage from said active filter is in excess of a predetermined threshold; and

power supply stop means for stopping power to be supplied to said active filter control means when the output voltage from said active filter is in excess of the predetermined threshold.

18. An air conditioning device, comprising:

rectification means for rectifying an AC voltage outputted from an AC power source;

smoothing means for smoothing the rectified AC voltage prior to conversion into a DC voltage;

DC voltage-AC voltage conversion means for converting, by chopping, the DC voltage from said smoothing means into an AC voltages, whose voltage and frequency vary, to be applied to a power compressor;

an active filter, formed between said rectification means and said smoothing means, for shaping an input current to be an approximate sine wave almost in phase with an input voltage;

output voltage detection means for detecting an output voltage from said active filter;

error detection means for detecting a difference between the output voltage and a preset reference voltage;

output control means for controlling the output voltage to be maintained constant based on the difference; and

limiting means for limiting the difference between the output voltage and the reference voltage to be not more than a predetermined value when starting up said active filter.

19. An air conditioning device, comprising:

rectification means for rectifying an AC voltage outputted from an AC power source;

smoothing means for smoothing the rectified AC voltage prior to conversion into a DC voltage;

DC voltage-AC voltage conversion means for converting, by chopping, the DC voltage from said smoothing means into an AC voltage, whose voltage and frequency vary, to be applied to a power compressor;

an active filters, formed between said rectification means and said smoothing means, for shaping an input current to be an approximate sine wave almost in phase with an input voltage by adjusting a flow of current into said smoothing means by switching a switching element;

zero cross detection means for detecting a zero cross point of the input voltage of said active filter; and

activation means for starting up said active filter at a zero cross point of the input voltage.

20. An air conditioning device, comprising:

rectification means for rectifying an AC voltage outputted from an AC power source;

smoothing means for smoothing an AC voltage rectified by said rectification means to be converted into a DC voltage;

a DC voltage-AC voltage conversion means for converting by chopping the DC voltage from said smoothing means into an AC voltage whose voltage and frequency vary to be applied to a power compressor;

an active filter formed between said rectification means and said smoothing means, said active filter including a choke coil and shaping an input current to be an approximate sine wave almost in phase with an input voltage by adjusting a flow of current into said smoothing means through said choke coil by switching a switching element; and

inductance alternation means for increasing an inductance of said choke coil for a predetermined time after starting up said active filter.

21. An air conditioning device, comprising:

rectification means for rectifying an AC voltage outputted from an AC power source;

smoothing means for smoothing the rectified AC voltage prior to conversion into a DC voltage;

DC voltage-AC voltage conversion means for converting, by chopping, the DC voltage from said smoothing means into an AC voltage, whose voltage and frequency vary, to be applied to a power compressor;

an active filters, formed between said rectification means and said smoothing means and including, a choke coil for shaping an input current to be an approximate sine wave almost in phase with an input voltage by adjusting a flow of current into said smoothing means through said choke coil by switching a switching element; and

inductance incrementing means for increasing an inductance of said choke coil for a predetermined time after starting up said active filter.

22. An air conditioning device, comprising:

rectification means for rectifying an AC voltage outputted from an AC power source;

smoothing means for smoothing the rectified AC voltage prior to conversion into a DC voltage;

DC voltage-AC voltage conversion means for converting, by chopping, the DC voltage from said smoothing means into an AC voltage, whose voltage and frequency vary, to be applied to a power compressor;

an active filter, formed between said rectification means and said smoothing means, for shaping an input current to be an approximate sine wave almost in phase with an input voltage and for boosting an input voltage based on a boost ratio;

AC voltage detection means for detecting an AC voltage of said AC power source;

voltage rise setting means for setting the boost ratio according to the AC voltage of said AC power source; and

active filter control means for controlling the output voltage from the active filter based on the set boost ratio.

23. An air conditioning device, comprising:

rectification means for rectifying an AC voltage outputted from an AC power source;

smoothing means for smoothing the rectified AC voltage prior to conversion into a DC voltage;

DC voltage-AC voltage conversion means for converting, by chopping, the DC voltage from said smoothing means into an AC voltage, whose voltage and frequency vary, to be applied to a power compressor;

an active filter, formed between said rectification means and said smoothing means, for shaping an input current to be an approximate sine wave almost in phase with an input voltage by adjusting a flow of current into said smoothing means by switching a switching element;

input voltage detection means for detecting an input voltage to said active filter;

waveform generation means for generating an approximate sine wave according to a phase angle of the input current of aid active filter;

phase synchronization means for making the approximate sine wave in phase with the input voltage of said active filter; and

switching control means for controlling a switching of said switching element based on the approximate sine wave in phase with the input voltage.