JP2006322675A - Fan motor controller of air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly comfortable air conditioner of which generation of sound noise, vibration and noise caused by controlling rotation number of an AC fan motor are reduced, in a fan motor controller of the air conditioner. <P>SOLUTION: The fan motor controller consists of the AC fan motor 3 for rotating a fan, a micro computer 1 for controlling the rotation number of the AC fan motor 3 and a semiconductor switching element (a fan motor driving means 2) with a zero cross detection function for switching on/off by control signal asynchronous with a power source cycle output from the micro computer 1. As the control signal is asynchronous with the power source cycle, rotation pulsation and vibration at a specific frequency of the AC fan motor 3 are not generated. In addition, as the semiconductor switching element with the zero cross detection function switches on/off at a zero cross point regardless of the control signal, noise is not generated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an air conditioner that is controlled by a microcomputer and performs cooling and heating, and more particularly to a control device that controls the rotational speed of an AC fan motor used in a blower.

  In an air conditioner that performs cooling and heating, the rotational speed of the fan motor is controlled in the outdoor unit of the air conditioner according to various operation mode settings of the cooling and heating and indoor and outdoor temperatures. Conventionally, a phase control method is known as a method for controlling the rotational speed of an AC fan motor. FIG. 4 is an overall configuration diagram of a conventional rotational speed control apparatus based on phase control disclosed in Patent Document 1, and FIG. 5 is a control flowchart of the conventional rotational speed control apparatus.

  In FIG. 4, reference numeral 61 denotes an AC power supply. One of the AC power supplies 61 is connected to the AC motor 63 through the triac 62, and the other is connected to the AC motor 63 and the zero cross timing detection means 67. The output of the zero cross timing detection means 67 is connected to the phase control output means 66. A rotation speed detecting means 64 is connected to the AC motor 63, and an output of the rotation speed detecting means 64 is connected to a phase control output means 66 through an output determining means 65. The output of the phase control output means 66 is connected to the triac 62.

  Next, the operation of the rotational speed control will be described using the flowchart shown in FIG. In step S <b> 101, the rotation speed detection unit 64 detects the current rotation speed of the AC motor 63. In step S102, the rotational speed output from the rotational speed detection means 64 is compared with a preset target rotational speed. If the rotational speed is outside the allowable range of the target rotational speed, the zero cross timing detection means 67 is determined in step S103. The phase control output means 66 sets the conduction angle by shifting the trigger point position with respect to the zero cross timing from the previous time, operates the triac 62 to bring the AC motor 63 close to the target rotational speed, and returns to step S101. If the target rotational speed is within the allowable range in step S102, the phase control unit 66 does not change the conduction angle setting in step S104, and the process returns to step S101.

As a conventional technique for controlling the rotational speed, for example, Patent Document 2 discloses that a switch connected between an AC power source and an AC motor is turned on / off by changing a duty ratio of a switching signal for on / off control. A method for controlling the rotational speed is shown. In the technique of the cited document 2, the switch is turned on and off regardless of the zero crossing of the power supply waveform.
JP-A 64-55089 JP 2000-179925 A

  According to the conventional control method as shown in the above cited reference 1, as shown in FIG. 3 (b), since the switching element is turned on when the power supply voltage is other than the zero cross point, it is abrupt when the switching element is turned on. Inrush current flows. Therefore, the problem that a harmonic and noise generate | occur | produce by this inrush current occurred. Further, since the energization rate is fixed for each period of the power supply waveform under a predetermined condition (in the example of FIG. 3B, t2 is constant for each period under the predetermined control condition), the fixed energization Rotation pulsation occurs at a specific frequency based on the rate, which causes problems such as generation of vibrations and noises and discomfort to the user.

  The present invention has been made to solve the above-described problems, and by turning on and off at the zero cross point of the AC power supply, a sudden inrush current is eliminated to suppress generation of harmonics and noise, and to the motor. An object of the present invention is to provide a fan motor control device for an air conditioner capable of minimizing vibration and noise at a specific frequency by randomly changing an energization rate.

In order to solve the above problems, the present invention mainly adopts the following configuration.
An air conditioner comprising: an outdoor unit having a compressor, a four-way valve, and an outdoor heat exchanger; an indoor unit having a two-way valve and an indoor heat exchanger; and a pipe connecting the outdoor unit and the indoor unit. ,
The outdoor unit has an AC fan motor whose rotational speed is controlled based on the cooling / heating operation mode setting and the indoor and outdoor temperatures,
The AC fan motor is driven by fan motor driving means comprising a semiconductor switching element having a zero cross detection function of the waveform of the AC power supply,
Control signal determining means for determining a switching element control signal to the semiconductor switching element based on the operation mode setting and the indoor / outdoor temperature on the upstream side of the fan motor driving means,
With the switching element control signal and the zero-cross detection function, the rotational speed is controlled by turning on / off the AC power supply at random using a half-wave component from the zero-cross of the AC power supply waveform as a conduction unit.

  According to the present invention, it is possible to eliminate noise, vibration, and noise generated by controlling the rotational speed of the AC fan motor, and to improve the comfort and commerciality of the air conditioner.

  A fan motor control device for an air conditioner according to an embodiment of the present invention will be described in detail below with reference to FIGS. FIG. 1 is a block diagram showing the overall configuration of a fan motor control device for an air conditioner according to an embodiment of the present invention. FIG. 2 is a flowchart showing the operation of the fan motor control device according to this embodiment. FIG. 3 is a timing waveform chart showing the control method according to the embodiment of the present invention in comparison with the control method of the prior art.

  In FIG. 1, 3 is a fan motor for rotating a fan, 4 is a rotation speed detecting means for detecting the rotation speed of the fan motor 3, and 8 is a preset rotation speed of the fan motor 3 (operation during cooling and heating). A rotational speed comparison means for comparing the detected rotational speed and the detected rotational speed based on the mode, indoor / outdoor temperature and AC power supply frequency, and outputting the rotational speed difference; Control signal correcting means 5 for correcting the duty ratio of the control signal for controlling the rotational speed of the fan motor 3 from the rotational speed difference output from the comparing means 8 is a zero cross timing detecting means for detecting the zero cross timing of the commercial power supply. , 6 is a commercial power frequency determining means for determining the commercial power frequency (50 Hz or 60 Hz) based on the zero cross signal from the zero cross timing detecting means 5.

  Reference numeral 7 denotes the fan motor 3 having the highest efficiency at 50 Hz or 60 Hz, which is stored in the EEPROM of the microcomputer 1, depending on the output of the commercial power supply frequency determination means 6, various operation modes of the air conditioner, and indoor and outdoor temperatures. Control data (this control data is an on / off switching signal, and an on / off duty ratio is determined in advance by experiments or the like, corresponding to switching element control signal data in FIG. 3 described later). Control data determining means. Here, the microcomputer 1 includes a commercial power supply frequency determination means 6, a control data determination means 7, a rotation speed comparison means 8, and a control signal correction means 9.

  Reference numeral 2 denotes fan motor driving means for rotating the fan motor 3 in accordance with the output from the control signal correcting means 9. The fan motor driving means 2 is a semiconductor element incorporating a zero-cross detection function, and for example, a solid state relay (SSR) may be used (this SSR includes a triac inside). When an input control signal is turned on in this semiconductor element, the built-in zero cross circuit triggers an alternating voltage near zero voltage, and the triac is turned on. Next, when the control signal is turned off, the load current is turned off in the vicinity of zero of the load current (which is maintained until zero) by the triac latching action.

  In other words, as will be apparent from the waveform diagram of FIG. 3A described later, when the commercial power supply is zero-crossed when the switching element control signal is on, the zero-crossed power supply is turned on. Regardless of the on / off state, the power supply is latched and turned on until the next zero cross. If the control signal is turned off when the commercial power supply is at zero cross, the next power supply is turned off.

  Next, the operation of the fan motor control device according to the present embodiment will be described with reference to the program flowchart of FIG. When the program starts, the commercial power supply zero cross pulse detected by the zero cross timing detection means 5 is input to the commercial power supply frequency determination means 6 in step S11. Next, the time interval of the zero cross pulse is measured by the commercial power supply frequency determination means 6, and it is determined in step S12 whether it is 50 Hz or 60 Hz. From this result, in step S13, it is determined whether to use preset control data for 50 Hz or 60 Hz. Here, the control data determination means 7 sets control data in advance based on various operation modes and indoor and outdoor temperature environments as described above, and further uses the commercial power supply based on the set control data. The control data is also determined by the frequency.

  The fan motor 3 is driven in S14 based on the control data determined in step S13. Since this control data is output asynchronously with the power cycle, the energization rate to the fan motor 3 is, for example, As shown in FIG. 3 (a), the energization rate changes randomly at 100% in the period T1 and 50% at T2. In other words, the control data to be displayed as the switching element control signal in FIG. 3A is set regardless of the commercial power cycle (the operation mode, the indoor / outdoor temperature, and the commercial power frequency). In other words, the energization rate differs between the T1 and T2 periods even under the same control conditions (the operation mode, temperature, and power supply frequency are the same). On the other hand, in the prior art, as shown in FIG. 3B, the triac trigger signal as control data is output in synchronization with the power cycle, and the fan motor applied voltage waveform is energized under the same control conditions. The rate becomes a constant value, and the applied voltage having the same waveform generates vibration and noise at the specific frequency.

  As described above, assuming that the vibration occurs at a certain natural frequency when the energization ratio of the fan motor applied voltage is constant, in the related art, the vibration is sustained when the natural frequency is met. In the embodiment, as shown in FIG. 3A, even when the fan motor applied voltage is under the same control condition, the energization cycle is not constant, so that the vibration does not continue.

  A specific description will be repeated with reference to FIG. 3A. The “switching element control signal” shown in the middle stage of FIG. 3A is an output signal from the control data determining means 7, The output signal is a signal in which the “triac trigger signal” shown in FIG. 3B is synchronized with the power cycle, while the control data determining means 7 does not depend on the waveform cycle of the AC power source. It is an on / off signal having an arbitrary duty ratio that is uniquely determined based on an input signal. A voltage for each half-wave component of the AC power supply is generated by the switching element control signal and the AC power supply zero-cross signal from the zero-cross circuit built in the semiconductor switching element (this generation mode is as described above), and the fan motor It is applied to the fan motor as an applied voltage (the lower diagram in FIG. 3A).

  Here, when the duty ratio of the switching element control signal is variably controlled (the change of the duty ratio basically depends on the determination method of the control data determination means 7, but the output from the rotation speed comparison means 8 is not limited thereto. The number of half-wave components to be energized changes every predetermined power supply cycle (T1 and T2 in FIG. 3A). In the specific example shown in FIG. 3, energization is 100% in the T1 period and 50% in the T2 period (25% energization if one half-wave component is energized in the T2 period). In this way, the 100% energization period and the 50% energization period as described above appear by the constant output value determined by the control data determination means 7 based on the input signal data, and thus the vibration continues. There is no need to do it. At this time (under the constant output value), what percentage of the energization period for each period of T1 and T2 can be appropriately designed according to the waveform shaping method of the switching element control signal. Under the control condition that the output value from the control data determining means 7 is constant (the output value naturally varies if the control condition is changed), the half-wave component from the zero cross of the AC power supply waveform is set as the energization unit. It is one of the features of the present invention that the rotational speed of the fan motor is controlled by turning on / off the AC power supply at random (by appropriately turning on / off the half wave component of the AC power supply at appropriate power supply cycles).

  Next, the rotational speed is detected in step S15, and the duty of the control data is set so that the rotational speed is set from the difference between the predetermined rotational speed set in advance in steps S16 and S17 and the detected actual rotational speed. Correct the ratio. Thereafter, the process returns to step S14 to repeat this loop. The air conditioner has, as its basic structure, an outdoor unit having a compressor, a four-way valve, an expansion valve or a capillary tube and an outdoor heat exchanger, and an indoor unit having a two-way valve and an indoor heat exchanger. It comprises a refrigeration cycle connected to the machine by piping.

  As described above, in the embodiment of the present invention, when the semiconductor switching element is turned on and off, a zero cross timing detection function is provided, and the inrush current is eliminated by turning on and off at the zero cross point of the AC power supply regardless of the control signal. It suppresses the generation of harmonics and noise. Also, by making the control signal asynchronous with the cycle of the AC power supply (see FIG. 3 (a)), the energization rate to the motor fluctuates randomly (in units of 1/2 cycle of the power supply frequency), and vibration at a specific frequency And to minimize noise.

  Furthermore, in this embodiment, unlike the phase control, once the 50 Hz / 60 Hz is determined by the zero cross timing detection means (for example, once at the beginning of use of the air conditioner), the commercial control is performed thereafter. Since it is not necessary to input a frequency signal, even if noise is superimposed on the commercial power supply, the rotation speed control of the fan motor is not affected (in the conventional control method shown in FIG. Are superimposed on each other and become zero, it will affect the generation of the zero-cross signal, and in turn will adversely affect the generation of the fan motor applied voltage waveform).

  As described above, the fan motor control device for an air conditioner according to an embodiment of the present invention switches a semiconductor switch connected between an AC motor and an AC power source and having a zero-cross timing detection function, and turns this semiconductor switch on and off. And a control unit that outputs a control signal asynchronous to the power supply frequency and controls the rotational speed of the AC motor by changing the duty ratio of the control signal.

  Further, the fan motor control device of the present embodiment has a zero cross timing detection means for detecting the zero cross timing of the AC power supply, and a frequency determination means for determining the frequency of the AC power supply from the output from the zero cross timing detection means, Control data determination means for determining whether to use preset control data for 50 Hz or 60 Hz according to the frequency determined by the frequency determination means (as the input signal, various operation mode settings for air conditioning and indoor / outdoor use) In addition to this, the frequency of the AC power supply is also used as the input signal).

  In addition, the fan motor control device of the present embodiment includes a rotation number detection unit that detects the rotation number of the AC motor, an actual rotation number detected by the rotation number detection unit, and a predetermined rotation number that is defined in advance ( Rotational speed comparison means for comparing the rotational speed determined by design matters) and means for correcting the duty ratio of the control signal for turning on / off the semiconductor switch and maintaining the rotational speed of the AC motor constant by the output from the rotational speed comparison means It is characterized by providing.

It is a block diagram which shows the whole structure of the fan motor control apparatus of the air conditioner which concerns on embodiment of this invention. It is a flowchart which shows operation | movement of the fan motor control apparatus which concerns on this embodiment. It is a timing waveform chart which shows the control system regarding the embodiment of the present invention by contrast with the control system of a prior art. It is a block wiring diagram which shows the fan motor control apparatus of the air conditioner regarding a prior art. It is a flowchart which shows operation | movement of the fan motor control apparatus of the air conditioner regarding a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Microcomputer 2 Fan motor drive means 3 Fan motor 4 Rotation speed detection means 5 Zero cross timing detection means 6 Commercial power supply frequency determination detection means 7 Control data determination means 8 Rotation speed comparison means 9 Control signal correction means 61 AC commercial power supply 62 Triac 63 Fan motor 64 Rotational speed detection means 65 Output determination means 66 Phase control output means 67 Zero cross timing detection means

Claims (4)

An air conditioner comprising: an outdoor unit having a compressor, a four-way valve, and an outdoor heat exchanger; an indoor unit having a two-way valve and an indoor heat exchanger; and a pipe connecting the outdoor unit and the indoor unit. ,
The outdoor unit has an AC fan motor whose rotational speed is controlled based on the cooling / heating operation mode setting and the indoor and outdoor temperatures,
The AC fan motor is driven by fan motor driving means comprising a semiconductor switching element having a zero cross detection function of the waveform of the AC power supply,
Control signal determining means for determining a switching element control signal to the semiconductor switching element based on the operation mode setting and the indoor / outdoor temperature on the upstream side of the fan motor driving means,
The air conditioner is characterized in that, by the switching element control signal and the zero cross detection function, the AC power supply is turned on and off at random by using a half wave component from the zero cross of the AC power supply waveform as a conduction unit. Fan motor control device. In claim 1,
The fan motor control device for an air conditioner, wherein the switching element control signal input to the semiconductor switching element is asynchronous with a waveform of the AC power supply. In claim 1 or 2,
Detecting the actual rotational speed of the AC fan motor,
Compare the detected actual rotational speed with a preset rotational speed to obtain the rotational speed difference,
A fan motor control device for an air conditioner, wherein a duty ratio of the switching element control signal is corrected based on the difference in rotation speed. In claim 1, 2 or 3,
A zero cross timing detecting means for detecting zero cross timing of the AC power supply is provided,
Determine the frequency of the AC power supply using the zero cross timing detected by the detection means,
The fan motor control device for an air conditioner according to claim 1, wherein the AC power supply frequency becomes one determining factor of the switching element control signal by inputting the determined AC power supply frequency to the control signal determining means.

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