The application is that application number is: 200710023497.9; The applying date is: on June 6th, 2007; Denomination of invention is: the dividing an application of low-voltage working fixed speed air conditioner and control method thereof.
Summary of the invention
The present invention is for avoiding above-mentioned existing in prior technology weak point, a kind of control method of low-voltage working fixed speed air conditioner is provided, and this air-conditioner is should be able to be under 180V even lower voltage conditions normal to be started and keep operation; When power network fluctuation, can avoid occurring abnormal sound; Can be when brownout stoppage protection initiatively, and can be after voltage recovers, fast automatic recovery normally moves.
Technical solution problem of the present invention adopts following technical scheme.
Low-voltage working fixed speed air conditioner of the present invention is to be made of indoor set, off-premises station, refrigeration system and correspondent control circuits, and its control circuit includes:
The indoor motor rotating-speed control circuit is made of zero cross detection circuit, motor-drive circuit and speed feedback circuit; Described zero cross detection circuit is by the rectifier bridge full wave rectified signal of sampling, with triode Q
2, resistance R
47And capacitor C
19Form the zero cross signal shaping circuit, with indoor motor M
1Built-in Hall element as the motor speed detection signal, but with the controllable silicon U of two-way admittance
7Executive component as the control motor speed; The zero cross detection circuit output signal in motor-drive circuit through photoelectrical coupler U
8Be coupled to and be used to control controllable silicon U
7The bidirectional triode thyristor U of the angle of flow
7Control end;
The compressor current foldback circuit is with current transformer TR
1For compressor over-current detection element, with the relay R L of controlled system compressor start and stop
3As performer, the protective current value of the protective current value of current foldback circuit less than the internal or external thermal protector of compressor is set;
On compressor operating electric capacity, be arranged in parallel auxiliary actuator PTC;
One group of electrical network pressure detection tap is set as the network voltage detection port the secondary of power transformer T;
The outdoor motor winding is provided with at least two different rotating speed shelves interface circuits, and corresponding to different line voltages, the outdoor motor winding inserts on the rotating speed shelves interface circuit of correspondence by the relay on the distinct interface;
Structure of the present invention also is to be provided with the outer dish temperature sensor RT of outdoor condenser
2, with described outer dish temperature sensor RT
2Temperature detection signal insert changeover control signal as outdoor motor at different rotating speeds shelves interface circuit.
The characteristics of the control method of low-voltage working fixed speed air conditioner of the present invention are:
Motor speed is adjustable in the control room, and when grid voltage change, the silicon controlled angle of flow in the adjusting motor-drive circuit is with rotating speed of motor in the equalization chamber;
Control outdoor motor different rotating speeds shelves are convertible, and under the line voltage of different range, and/or outside under the different outer dish temperature of machine condenser, outdoor motor is operated on the different rotating speed shelves;
Control compressor overcurrent protection, before system's thermal protector input protection, the shutdown overcurrent protection that drops into compressor with the protective current value that is lower than thermal protector, and the setting-up time after dropping into protection is finished restarting of compressor automatically.
Compared with the prior art, beneficial effect of the present invention is embodied in:
1, the present invention by closed-loop control, makes indoor motor because indoor motor is provided with rotating-speed control circuit under high voltage, and rotating speed does not rise, and noise does not increase; Under low-voltage, rotating speed is step-down not, and under the low-voltage heating condition, the heating effect of air-conditioner is variation not.
2, the present invention is provided with overcurrent protective device to compressor, and increases the auxiliary actuator PTC that is arranged in parallel on compressor operating electric capacity.Based on this circuit structure, after the compressor overcurrent protection occurring, can recover normal operation fast and automatically; When brownout, initiatively realize stoppage protection, avoid compressor overload work.And can be after voltage recovers, fast automatic recovery normally moves.Solved a difficult problem that is difficult to start voluntarily behind the common fixed speed air conditioner " jumping machine ".
3, the present invention by control, makes outdoor motor owing to be provided with the network voltage detection port and outdoor motor is provided with many grades of settings under different line voltages, is operated in different gears, has solved the influence of voltage to rotating speed.
4, the present invention makes off-premises station be operated in different rotating speed shelves under different operating modes by the outer dish temperature sensor of outdoor condenser is set, and has solved the influence of environment to condensation effect.Reduced the load of compressor under bad working environments effectively; Increased the adaptive capacity of compressor at low voltage operating; Motor can avoid occurring abnormal sound when power network fluctuation.
5, the present invention adapt to voltage range wide, adapt to that the power network fluctuation ability is strong, working stability is reliable, the widening of the produce market that is highly advantageous to.
6, the present invention does not change the system architecture of existing fixed speed air conditioner, and the suitable adjustment by control circuit can realize, and is easy to implement.
The specific embodiment
Referring to Fig. 1, system's setting routinely, present embodiment is made of indoor set, off-premises station, refrigeration system and correspondent control circuits; During refrigeration, low pressure, low-temperature refrigerant steam in the refrigeration system are sucked by compressor, drain into the off-premises station heat exchanger behind the compressed superheated steam for high pressure, high temperature; Simultaneously the outdoor air that sucks of the outdoor side axial off-premises station heat exchanger of flowing through is taken away the cold-producing medium liberated heat, makes the refrigerant vapour of high pressure, high temperature be condensed into highly pressurised liquid.Highly pressurised liquid flows into the indoor set heat exchanger through throttle capillary tube step-down cooling, and evaporates under corresponding low pressure, draws ambient heat; Simultaneously the indoor axial-flow fan makes between the fin of machine heat exchanger in the continuous inlet chamber of room air and carries out heat exchange, and is sent to the gas that turns cold after the heat release indoor.So, indoor-outdoor air constantly circulates, and reaches the purpose that reduces temperature.When heating, utilize the compression condensation heat of refrigeration system to heat room air, low pressure, low-temperature refrigerant liquid evaporate heat absorption in evaporimeter, and the heat release condensation in condenser of high-temperature high-pressure refrigerant gas.When heating, heat pump changes the loop direction of cold-producing medium by cross valve, become condenser when heating as the indoor set heat exchanger of evaporimeter when making original refrigeration work, originally become evaporimeter when heating as the off-premises station heat exchanger of condenser during refrigeration work, refrigeration system is in outdoor heat absorption like this, indoor heat release realizes the purpose that heats.
The control circuit of present embodiment relative set comprises:
Shown in Figure 2, zero cross detection circuit is set, the full wave rectified signal of in the rectification bridge circuit, sampling, process triode Q2 and resistance R 47, capacitor C 19 are formed shaping circuits, insert CPU external interrupt mouth to be shaped to impulse wave Crossing, trigger external interrupt.
Shown in Figure 3, the indoor machine motor drive circuit is set, CPU produces a trigger impulse DRIVE FAN1, and the control end through photoelectrical coupler U8 is coupled to bidirectional triode thyristor U7 makes controllable silicon U7 conducting.
Shown in Figure 4, indoor motor speed feedback circuit is set, after the indoor motor M1 running, 3 pulse/commentaries on classics of Hall element HALL output of electric machine built-in, Q1 is shaped as square wave through triode, sends into CPU external interrupt mouth, CPU counts the pulse of sending into, thereby realizes the measurement to wind speed.
Fig. 2, Fig. 3, Fig. 4 have constituted the indoor motor rotating-speed control circuit.Zero cross detection circuit (shown in Figure 2) full wave rectified signal of sampling in the rectification bridge circuit is formed shaping circuits through triode Q2 and resistance R 47, capacitor C 19, is shaped to impulse wave Crossing and inserts CPU external interrupt mouth, can trigger external interrupt.CPU is interrupting handling in the subprogram, open the timing function of timer internal, such as timing 4ms, produce a trigger impulse DRIVE FAN1 by CPU behind the 4ms, send into motor-drive circuit (shown in Figure 3), be coupled to the control end of bidirectional triode thyristor U7 through photoelectrical coupler U8, make controllable silicon U7 conducting.AC220V gives indoor motor M1 power supply.After the indoor motor M1 running, speed feedback circuit (shown in Figure 4) is sent in 3 pulse/commentaries on classics of Hall element HALL output of electric machine built-in, be shaped as square wave through triode Q1 again, send into CPU external interrupt mouth, CPU counts the pulse of sending into, thereby realizes the measurement to wind speed.And compare with the umber of pulse of the corresponding rotating speed of CPU inner setting, adjust the timing of timer internal.Can control the ON time of AC220V in every half period by the change of timing, thus the rotating speed of motor M 1 in the control room.
Shown in Figure 5; the compressor current foldback circuit is set and is arranged in parallel auxiliary actuator PTC on compressor operating electric capacity; with current transformer TR1 is compressor over-current detection element; as performer, the protective current value of circuit protection current value less than the internal or external thermal protector of compressor is set with controllable relay R L3.TR1 detects compressor control line COMP and goes up current variation.When electric current increased suddenly, the current transformer output current also increased thereupon, through diode D2 rectification, current/voltage-converted, LPF, from AD2 end output dc voltage signal.CPU is by to the AD of AD2 terminal voltage conversion, the variation of gathering the perception compressor current, when the overtension of AD2 end, exceeds the protective current value of setting, CPU cut off the compressor control relay control signal COMPRESSOR.Thereby realized protection to compressor.With reference to compressor specifications and various test data, determine a protective current value, initiatively realize the compressor shutdown protection, and after the overcurrent protection generation is set in software, the function that certain interval of time resets automatically.
The setting of auxiliary actuator PTC can effectively improve the detent torque of compressor, reduces starting current, makes compressor be easier to start.
Shown in Figure 6, the network voltage detection terminal circuit is set, be power transformer secondary one group of electrical network to be set to press and detect tap.The network voltage detection tap (Fig. 6) of setting up has separately farthest reduced the influence of load to accuracy of detection.Through diode D4 rectification, after capacitor C 13 filtering, from AD1 end output dc voltage signal, CPU is by to the AD conversion of AD1 terminal voltage, the variation of gathering the perception line voltage from the voltage of transformer T time level 3,4 ends output.
Many rotating speeds of outdoor motor shelves interface is set, selects top gear H, mid ranger M or many grades of interfaces of low or first gear L of inserting according to line voltage.When grid voltage change, according to the voltage of Fig. 7---rotating speed transformational relation table, the rotating speed of outdoor motor is controlled.When voltage rose, during greater than dy2, CPU exported MID signal (Fig. 6), drives through triode Q4, relay R L6 gets electric adhesive, and outdoor motor mid ranger M connects, during greater than dy4, and CPU output LOW signal, drive through triode Q5, relay R L7 gets electric adhesive, and outdoor motor low or first gear L connects; When voltage descends, during less than dy3, CPU output MID signal, outdoor motor mid ranger M connects, and during less than dy1, CPU output HIGH signal drives through triode Q3, and relay R L5 gets electric adhesive, and outdoor motor top gear H connects.
Shown in Figure 8, in concrete the enforcement, dish sensor can also be provided with again on outdoor condenser outside increases outer dish sensor temperature Acquisition Circuit, and the variation of NTC thermistor RT2 is converted to voltage change, holds the output dc voltage signal from AD3.CPU changes, gathers the variation of the outdoor condensation temperature of perception by the AD to the AD3 terminal voltage, the control mode of outdoor motor is included under the refrigeration situation, when the overtension of AD3 end, exceed setting value, outdoor motor inserts the top gear interface, when the brownout of AD3 end, be lower than setting value, then outdoor motor inserts the low or first gear interface; Otherwise when heating.
Embodiment:
Implement on split wall-hanging air conditioner KFR-3211GW/D, KFR-3201GW/D type, led module, two kinds of display modes of LED lamp are adopted in indoor demonstration respectively.According to experiment, when delivery temperature is 100 ℃, the built-in protector of compressor action current be about 9A, therefore, the overcurrent protection value is set at 8.1A, so that reliable implement protection.
The overcurrent protection manner of execution: compressor current is greater than 8.1A and continue 5 seconds, stops compressor, after the time of setting, opens again after 9 minutes.According to the detected input voltage of voltage detecting mouth on the automatically controlled plate, when the input voltage rising, during greater than 200V, outdoor motor is reduced to the middling speed operation; During greater than 227V, outdoor motor is reduced to low cruise; When input voltage decline, during less than 223V, outdoor motor is raised to middle-grade operation; During less than 196V, outdoor motor is raised to high-grade operation.When line voltage is lower than certain value, by the demonstration of display screen, remind brownout in user man's this moment, when voltage is higher than certain value, remind user's overtension, notice preventing that household electrical appliance from damaging;
The design of outdoor motor third gear rotating speed.An auxiliary actuator PTC in parallel on compressor electric capacity, adopting rated voltage is the compressor of 200~220V.
Degradation proves; it is at the above voltage of 170V; the normal steady operation of energy; operating voltage is well below the 187V of GB regulation; cross when low when voltage pulsation, the each built-in thermal protector of compressor that all can shift to an earlier date of the over-current detection circuit of automatically controlled plate moves, for the operate as normal once more after a few minutes provides assurance; avoided the built-in protector of press to disconnect, the trouble of ability operate as normal after 40~60 minutes.The adding of auxiliary actuator PTC has reduced the starting current of press, has avoided the built-in protector of press in the moment that starts, and because of the excessive tripping of electric current, has guaranteed that press all can normally start (even under low-voltage) at every turn.