Accurately detect failure detector circuit and the method for ac fan operation conditions
Technical field
The present invention relates to a kind of failure detector circuit and method, the failure detector circuit of especially a kind of accurate detection ac fan operation conditions and method, belong to the technical field of ac fan fault detect.
Background technology
High-power electrical equipment is widely used in the industry-by-industry of society, such as powerful devices such as the energy, machinery, metallurgy, telecommunications owing to power grade is higher, caloric value is big, so heat dissipation problem is paid close attention to by everybody always, existing heat exchange means has: natural air heat loss through convection, air blast cooling, water-cooled etc. In air blast cooling is dispelled the heat, fan is one of most important parts, and its working condition directly affects the runnability of equipment. Owing to fan is in air channel, environment rather harsh, and it is in machinery rotation status, thus belong to easily worn part in the electrical apparatus, fault rate is significantly high, so fan failure detection is particularly important. The detection of existing fan failure has two kinds of thinkings, and one is to carry fault-signal output inside fan, is be monitored drawing fault-signal to fan peripheral auxiliary circuits in another.
Possesses the fan exported on the fan cost of fault-signal output much larger than the fault-free signal of same specification, and then weaken complete machine competitive advantage, additionally the shortcoming of this fault detection method can only detect the fault of fan itself, lack the communication (need nonetheless remain for peripheral auxiliary circuits fault-signal is processed) with control unit, and cannot and the driving signal of control unit between do logical judgment, if the circuit between control unit and fan breaks down (includes blower fan insurance open circuit, connection fault etc.) cause fan stall, fan cannot provide fault-signal and alert.
By the method that fan is carried out malfunction monitoring by peripheral auxiliary circuits, employing is had to seal in diode in fan circuit, when control unit sends driving signal, fan running, the conduction voltage drop of diode drives the former limit of photo-coupler, can pass through peripheral circuit, pass signal back control unit after the conducting of photo-coupler secondary, when fan breaks down, current vanishes, diode is without conduction voltage drop, and photo-coupler secondary obtains contrary signal, and then judgement fan failure, its principle schematic such as Fig. 1.
The shortcoming of this testing circuit is to detect the open fault of fan, and when short circuit occurs, diode also can turn on, and photo-coupler secondary obtains correct signal, thus cannot detect fan short trouble; Additionally need in fan major loop, seal in diode and rectifier bridge, be greatly increased power consumption, the loss calculation according to diode:
Pdiode=N*Vf*If
Wherein, VfFor the conduction voltage drop of diode, IfFor fan electrical current, N is Diode series quantity in loop. When this circuit is for powerful fan fault detect, the loss of diode and rectifier bridge can be very big, it is necessary to increases extra heat radiation and solves, and then the overall plan cost increased.
Although this circuit can realize the isolation of fault-signal and main circuit by photo-coupler, but the isolation Level that common optical coupler provides is relatively low, if needing to provide the isolation of the high class of insulation, it is necessary to selecting expanded letter optocoupler, its cost is several times of ordinary optical coupler.
Summary of the invention
It is an object of the invention to overcome the deficiencies in the prior art, it is provided that the failure detector circuit of a kind of accurate detection ac fan operation conditions and method, its compact conformation, accuracy of detection is high, and testing cost is low, wide accommodation, safe and reliable.
According to technical scheme provided by the invention, the failure detector circuit of described accurate detection ac fan operation conditions, including ac fan; Described ac fan is connected with the blower fan current detecting process circuit being used for detecting described ac fan operating current, described blower fan current detecting processes circuit by the operating current transmission of detection to control circuit, described control circuit is connected with ac fan by fan drive circuit, to drive ac fan by fan drive circuit; Being pre-stored with the first working current value during ac fan normal operation in control circuit, operating current and first working current value of detection are compared by control circuit; When the operating current detected and the first working current value do not mate, control circuit judges the operation troubles of output AC fan according to the driving RST exported to fan drive circuit.
The operation troubles of described control circuit output includes the open circuit of ac fan, short circuit or stall. Described blower fan current detecting processes circuit and includes the isolation for detecting electric current such as current transformer, hall effect sensor, diverter or giant magneto-resistance sensor or non-isolated detecting element.
When described blower fan current detecting processes circuit employing current transformer, the one end on the former limit of current transformer is connected with ac fan, the other end on the former limit of current transformer is connected with fan drive circuit, one end of the secondary of current transformer is connected with one end of the second resistance and one end of the 3rd resistance, the other end of current transformer secondary and the equal ground connection of the other end of the second resistance, the other end of the 3rd resistance is connected with the in-phase end of operational amplifier, the end of oppisite phase of operational amplifier is connected with the outfan of operational amplifier, and the outfan of operational amplifier is connected with control circuit.
Described fan drive circuit includes controllable silicon, and described silicon controlled controls end and is connected with the outfan of control circuit.
The fault detection method of a kind of accurate detection ac fan operation conditions, described ac fan operation conditions fault detection method comprises the steps:
A, obtain the operating current of ac fan, and by the transmission of described operating current in control circuit;
Described operating current is compared by b, control circuit with the first working current value of pre-stored;
C, when the operating current of described acquisition and the first working current value do not mate, control circuit is according to the duty to the condition adjudgement ac fan of fan drive circuit output drive signal; When ac fan is in malfunction, control circuit output fault-signal.
In described step c, when acquired operating current and the first working current value do not mate, when control circuit is to fan drive circuit output drive signal, control circuit determines the fault-signal of also output AC fan.
In described step a, utilizing blower fan current detecting to process circuit and obtain the operating current of ac fan, described blower fan current detecting processes circuit and includes the isolation for detecting electric current such as current transformer, hall effect sensor, diverter or giant magneto-resistance sensor or non-isolated detecting element.
When described blower fan current detecting processes circuit employing current transformer, the one end on the former limit of current transformer is connected with ac fan, the other end on the former limit of current transformer is connected with fan drive circuit, one end of the secondary of current transformer is connected with one end of the second resistance and one end of the 3rd resistance, the other end of current transformer secondary and the equal ground connection of the other end of the second resistance, the other end of the 3rd resistance is connected with the in-phase end of operational amplifier, the end of oppisite phase of operational amplifier is connected with the outfan of operational amplifier, and the outfan of operational amplifier is connected with control circuit.
In a kind of similar technical scheme, the fault detection method of a kind of accurate detection ac fan operation conditions, its described ac fan operation conditions fault detection method comprises the steps:
S1, obtain the operating current of ac fan, and by the transmission of described operating current in control circuit;
S2, obtain the running voltage at ac fan two ends, and by the transmission of described running voltage in control circuit;
S3, control circuit judge the duty of also output AC fan according to the working current value received and operational voltage value.
Advantages of the present invention: process circuit by blower fan current detecting and obtain the operating current of ac fan, adopts operating current as the foundation judging ac fan running status, and accuracy of detection is high, and testing cost is low, and the fault coverage of detection ac fan is wide; Control circuit can only judge whether ac fan exists operating current, judges whether ac fan is in malfunction, wide accommodation, it is possible to is simultaneous for multiple ac fan and carries out synchronous detecting, simple and compact for structure, safe and reliable.
Accompanying drawing explanation
Fig. 1 is the circuit theory diagrams of existing ac fan operation conditions detection.
Fig. 2 is the circuit block diagram of electric current mode of operation of fan of the present invention detection.
Fig. 3 is the circuit theory diagrams of the present invention.
Fig. 4 is the flow chart that control circuit of the present invention judges ac fan operation conditions.
Description of reference numerals: 1-control circuit, 2-fan drive circuit, 3-ac fan, 4-blower fan current detecting process circuit, 21-controllable silicon, 41-current transformer and 42-operational amplifier.
Detailed description of the invention
Below in conjunction with concrete drawings and Examples, the invention will be further described.
As shown in Figures 2 and 3: in order to quickly and accurately the operation conditions of ac fan 3 is detected, the present invention includes ac fan 3; Described ac fan 3 is connected with the blower fan current detecting process circuit 4 being used for detecting described ac fan 3 operating current, described blower fan current detecting processes circuit 4 by the operating current transmission of detection to control circuit 1, described control circuit 1 is connected with ac fan 3 by fan drive circuit 2, to drive ac fan 3 by fan drive circuit 2; Being pre-stored with the first working current value during ac fan 3 normal operation in control circuit 1, operating current and first working current value of detection are compared by control circuit 1; When the operating current detected and the first working current value do not mate, control circuit 1 judges the operation troubles of output AC fan 3 according to the driving RST exported to fan drive circuit 2.
Specifically, the operation troubles that ac fan 3 produces in running includes open circuit, short circuit or stall, and therefore the operation troubles of described control circuit 1 output includes the open circuit of ac fan 3, short circuit or stall. When ac fan 3 is opened a way, it is zero that blower fan current detecting processes the operating current of circuit 4 detection, and when ac fan 3 is in short circuit or stall, blower fan current detecting processes the operating current of circuit 4 detection higher than running current, namely can be higher than the first working current value. Control circuit 1 includes single-chip microcomputer, it would however also be possible to employ conventional micro-chip processor (or simple logic control circuit), and control circuit 1, according to the use environment of ac fan 3 and requirement, is previously stored with the first working current value; When the operating current and the first working current value that are obtained ac fan 3 by blower fan current detection circuit 4 are not mated, control circuit 1 is further according to or without the operation troubles judging ac fan 3 to fan drive circuit 2 output drive signal; When control circuit 1 is to fan drive circuit 2 output drive signal, control circuit 1 then judges that ac fan 1 is in failure operation state.
Described blower fan current detecting processes circuit 4 and includes the isolation for detecting electric current such as current transformer 41, hall effect sensor, diverter or giant magneto-resistance sensor or non-isolated detecting element.
Fig. 3 says: as described in blower fan current detecting process circuit 4 when adopting current transformer 41, the one end on the former limit of current transformer 41 is connected with ac fan 3, the other end on the former limit of current transformer 41 is connected with fan drive circuit 2, one end of the secondary of current transformer 41 is connected with one end of the second resistance R2 and one end of the 3rd resistance R3, the other end of current transformer 41 secondary and the equal ground connection of the other end of the second resistance R2, the other end of the 3rd resistance R3 is connected with the in-phase end of operational amplifier 42, the end of oppisite phase of operational amplifier 42 is connected with the outfan of operational amplifier 42, and the outfan of operational amplifier 42 is connected with control circuit 1. described fan drive circuit 2 includes controllable silicon 21, and the end that controls of described controllable silicon 21 is connected with the outfan of control circuit 1. fan drive circuit 2 can also adopt the circuit realiration such as relay. in the embodiment of the present invention, Fig. 3 does not show that the connection of control circuit 1 and controllable silicon 21 and operational amplifier 42.
As shown in Figure 2, Figure 3 and Figure 4: the fault detection method of described detection ac fan operation conditions comprises the steps:
A, obtain the operating current of ac fan 3, and by the transmission of described operating current in control circuit 1;
In the embodiment of the present invention, by obtaining the working current value foundation as detection ac fan 1 running status of ac fan 3; Processing circuit 4 by blower fan current detecting and obtain the operating current of ac fan 3, blower fan current detecting processes circuit 4 and includes current transformer 41, and the current value of current transformer 41 detection is transferred in control circuit 1 after being processed by operational amplifier 42. Blower fan current detecting processes the current value of circuit 4 detection and is zero current value or is higher than the first working current value.
Described operating current is compared by b, control circuit 1 with the first working current value of pre-stored;
After control electric current 1 receives working current value, can compare with the first working current value of storage, to carry out follow-up judgement.
C, when the operating current of described acquisition and the first working current value do not mate, the control circuit 1 duty according to the condition adjudgement ac fan 3 to fan drive circuit 2 output drive signal; When ac fan 3 is in malfunction, control circuit 1 exports fault-signal.
In the embodiment of the present invention, in order to realize the detection to ac fan 3 running status quickly and easily, described ac fan operation conditions fault detection method can also comprise the steps:
S1, obtain the operating current of ac fan 3, and by the transmission of described operating current in control circuit 1;
The method of described acquisition ac fan 3 operating current such as said method, can adopt corresponding current detecting to process circuit 4 and realize;
S2, obtain the running voltage at ac fan 3 two ends, and by the transmission of described running voltage in control circuit 1;
The method of described acquisition ac fan 3 two ends running voltage can adopt voltage sensor senses to realize.
S3, control circuit 1 judge the duty of also output AC fan 3 according to the working current value received and operational voltage value.
When control circuit 1 is when receiving running voltage and operating current, control circuit 1 can fast and effeciently judge the running status of ac fan 3 according to the relation of running voltage and operating current. Running voltage as received ac fan 3 when control circuit 1 is not zero, and when the operating current of ac fan 3 is zero, can determine that ac fan 3 is in open-circuit condition.
As shown in the above description, the operating current of blower fan current detecting process circuit 4 detection is likely zero current or higher than the first working current value. When the current value that blower fan current detecting processes circuit 4 detection is zero, control circuit 1 determines whether to fan drive circuit 2 output drive signal, when to fan drive circuit 2 output drive signal, ac fan 3 should be able to be in running order, being zero and during to fan drive circuit 2 output drive signal when blower fan current detecting processes the operating current of circuit 4 detection, control circuit 1 can interpolate that and output AC fan 3 is in open-circuit condition. When the operating current of blower fan current detecting process circuit 4 detection is not zero, when control circuit 1 is not to fan drive circuit 2 output drive signal, control circuit 1 judges that ac fan 3 is in malfunction; When the operating current of blower fan current detection circuit 4 detection is not zero, control circuit 1 is to fan drive circuit 2 output drive signal, and the size of the working current value of blower fan current detecting process circuit 4 detection acquisition and the first working current value control circuit time corresponding 1 is not judged and output AC fan 3 is in failure operation state; It is that control circuit 1 can export fault-signal when ac fan 3 is in failure operation state.Driving signal to fan drive circuit 2 output is exported by control circuit 1, it is possible to the convenient signal obtaining correspondence.
The present invention processes circuit 4 by blower fan current detecting and obtains the operating current of ac fan 3, adopts operating current as the foundation judging ac fan 3 running status, and accuracy of detection is high, and testing cost is low, and the fault coverage of detection ac fan 3 is wide; Control circuit 1 can only judge whether ac fan 3 exists operating current, judges whether ac fan 3 is in malfunction, wide accommodation, it is possible to is simultaneous for multiple ac fan 3 and carries out synchronous detecting, simple and compact for structure, safe and reliable.