Sensorless brushless dc motor control - fly-wheel diode

 Fly-wheel diode method is also called the "third phase conduction method", it is through the parallel inverter bridge on the power switch tube fly-wheel diode conduction and shut off state testing to determine the rotor position. This method applies to 120 ° conduction, three-phase six-step square wave permanent magnet brushless dc motor drive, the implementation scheme of main circuit and power required by the device PWM timing, respectively, as shown in figure 3 (a), (b). Below to T in the chopper, a T b - in the stage of conduction as an example to illustrate its working principle. When T a + from opening to shut off, if the winding self inductance, mutual generator set spare parts inductance are constant, the terminal voltage phase C can be expressed When ec = 0, ea + 4 = 0, V CE, V F is very small, can be ignored.

so the stream diode conduction approximation for the conditions of ec < 0, as long as the detection of D C - conducting state, can detect the C instead of electric potential zero; Appropriate delay, conduction T C - again, and again, can correctly commutation sequence, in turn trigger different power tube, drive motor rotation. wholesalemotor.blogspot.com Fly-wheel diode method the ac motor essence or the potential laws, only in the "disconnect" back emf zero detection have some change. This change in a certain extent, to broaden the motor lamination speed range, especially can widen the lower limit of motor speed, because the fly-wheel diode conduction voltage drop is small, as long as the sensorless brushless dc motor control - liuyunqian @ yeah - embedded learning can, CE and V F and V are usually small. In some applications, the minimum speed of the motor can even less than 100 r/min.

Research on the positioning control of asynchronous motor - fuzzy controller

 (1) to determine the fuzzy controller input variables and output variables (2) design control rules of fuzzy controller (3) establish the blurred with the fuzzy method (4) select the fuzzy controller input variable and output variable in the theory field and determine the parameters of the fuzzy controller (quantitative factor and scaling factor) (5) the preparation of the application of fuzzy control algorithm (6) the rational selection of sampling time fuzzy control algorithm electric vehicle motor Generally use a two-dimensional fuzzy controller to the change of the error and error as input variables, to control the change of the quantity of output. The design of the fuzzy control rules generally includes: choose the word set of input/output variables, define a fuzzy variable fuzzy subsets and establish the control rules of fuzzy controller. The word set input and output variables, as a general rule, be {NB, NM, NS, NO, PO, PS, PM, PB}. Fuzzy variables of the fuzzy subset is to determine the shape of membership function of fuzzy ac electric motor subset. General use normal distribution. Control rules available conditional statements describe, that is, If A and B, Then C, Then control rules table is established. 

Blur is the accurate quantity into fuzzy quantity, can use formula: Y = 12 X (a + b) / 2 / (b - a) accurate quantity is the actual range [a, b]. The output of the fuzzy control is a fuzzy quantity, it cannot directly control the controlled object, needs to be converted into precise volume. There are three methods: (1) selection of maximum membership degree method. The method is simple, less but the use of information; (2) take the median method; (3) the weighted average decision method, the use of information, but the large amount of calculation. Controller of the control algorithm can be written as if E = A (I) then EC = B (j) then U = C (ij) (I = 1, 2, 3,... m; j = 1, 2, 3,..., n) based on the sampling error, error change, can calculate the corresponding control quantity changes, to all the X, Y all the elements in the entire portfolio to calculate the corresponding control quantity change, U can be written as matrix (ij) (n * m) will be made table electricalmotor1.blogspot.com matrix, as A lookup table, to be stored in memory. After the real-time control, based on the fuzzy quantitative error value and error changes of look-up table directly, then set the scaling factor can be as the output to control the controlled object.

Generator maintenance procedures on a regular basis

 (1) under normal circumstances,every 7 days to start the generator no-load commissioning maintenance load of commissioning.5 - lOmin,every time with every month (2) disconnect the output of the generator automatic switch,puts selector switch to manual.(3) check the battery level,not enough level should be equipped with the electrolyte or distilled water,check the liquid proportion,in soda solution soaking and wipe up,coated with vaseline,then tighten the screw connection,and test ac induction motor the battery,battery voltage,and battery charging current at ordinary times.(4) remove the air filter,clean with gas and dust,after the sun to dry.Check the oil oil,such as turbidity or bad generator generator set should be replaced.Diesel engine running after 250 hours,water,oil,diesel oil filter should be changed.

(5) in diesel filter,should check whether the oil valve and valve in full capacity,with or without a fixed screw loose then manual oil pump,eliminate the air in the oil.(6) to check the cooling water plane position at ordinary times,change the water tank in the cooling water,in water,should add rust water.Then the shaking motor winding insulation resistance measurement.(7) to check whether there is oil leakage,the entire unit ground are in good condition,and then do a good job in cleaning unit.(8) open the control cabinet,check the fuse,screw contacts are motor vehicle in good condition,and then close the power control and help keep the oil temperature,water temperature sensor reset,and manual commissioning,oil pressure,output voltage,frequency,etc.(9) manually run 20 ~ 30 minutes,to simulate a power outage of commissioning,and check the ventilation,fire control system whether normal operation.After downtime,place electricalmotor1.blogspot.com selection switch on auto parts,close the output switch.

Total pressure starting current

If the three-phase squirrel cage induction motor,remember is 4 ~ 7 times,but not absolute. But the general requirements of ac induction motor 110kw the motor starting current is no more than the rated current of 2 ~ 5 times. Motor power for more than 30 kw motor is not suitable for frequent start,because more than 30 kw motor starting current is rated current commonly 6 to 12v mini generator motor 7 times,frequent can increase the motor temperature rise,may cause burning motor.Dc motor starting current formula Ist = (Un - Ea)/Ra,n = 0 when starting the armature voltage Ea = magnetic generator an nCe Ф = 0,and Ra is constant,so the rated voltage directly add to both wholesalemotor.blogspot.com ends of the armature,current can reach 10 ~ 30 times the rated current,therefore,usually only a small power dc motor can be used directly to start,the rest are not allowed to start directly.

Capacitor start motor

 In capacitor start motor,start capacitance and start winding string together,thus forming a LC circuit,the circuit has good phase shift (and thus have a very good starting torque).The resistance for the motor will also increase the cost.Fixed phase capacitor motor Another motor is fixed phase capacitor (PSC) motor (i.e.,capacitor motor) up and running.This kind of motor operation mode is similar to the capacitor start motor described above,but it does not have the centrifugal switch,so its secondary winding is connected to the grid.PSC motor is usually used in hair dryer,electric fans,blowers,and other need to change.Under the condition of invariable load by changing www.dongfeng-motor.com the running winding signal to achieve the purpose of make the motor run at different speeds.All six winding connection respectively,a three-phase motor can connect two winding together through the rest of the a winding capacitance connected to start winding to run into one capacitor start motor.The repulsion motor Repulsion motor is single-phase ac motor rotor winding,it is similar to ac/dc motor.In the repulsion motor armature with brush nipple rather than and in series with the magnetic field.

Already have a few kinds of repulsion motor into production use,but most of all,with repulsion start sensing (RS)-IR motor operation.RS-IR motor with a centrifugal switch all the short commutator connect together,so when it is up to full speed it will run in the form of induction induction motor sales motor.RS-IR was used in the motor under low temperature and low voltage per ampere provide large starting torque.In 2005,almost did not sell any type of repulsion motors.Single-phase ac synchronous motor Small single-phase motor can also be designed to be magnetized rotor.This does not require any motor in the rotor induction motor,so they will not be lower than the main frequency.Instead,they will be as the rotation frequency synchronization.Because of their high speed precision,this kind of motor is typically used in electric power mechanical clock,record machine and tape recorder; They are also used in such as ribbon machine and telescope driving mechanism requires precise time of equipment.Shaded pole type synchronous motor is one of them.Because of inertia,so it is difficult to the rotor from state stopped immediately accelerated to synchronous speed.This kind of motor usually need some special way to start.A variety generator rotor and stator of different Design with a small induction motor (it will share the same and the synchronous motor excitation coil and rotor) or one-way speed (guarantee the rotor startup positive speed) as the very light of the rotor.

How to correctly repairing and asynchronous motor?

Before repairing the motor should be prepared to all kinds of work,such as the tools used,remove the former work inspection and record.Remove the motor steps:(1),remove the pulley,or even the axis,before remove the pulley and the connecting shaft should be ready,when installation electric motor 12v 500w should be cleaning,clean rear wholesalemotor.blogspot.com can reset;(2),remove the end cover,remove the bearing cover first,then take the end cover,single phase asynchronous motor and make the front and back cover,when installation should press mark reset;(3),remove the rotor:wear-resisting of thick paper between the stator should be fitted to 5kw permanent magnet generator prevent damage to the stator winding,if the rotor is very heavy,lifting equipment installation available when the rotor to check whether there is sundry,inside the stator and shaft extension end end cover put on first,then the rotor load along with the fan and the back cover.

Three-phase asynchronous motor wiring diagram

Three-phase asynchronous motor wiring diagram:three-phase three-phase motor stator winding of each phase winding has two thread ends.A head is called the head end,on the other side called terminal.Provisions of the first phase winding head end with that D 1,end in 4 D;acmotor2.blogspot.com The second phase winding head end with D2,said end D5 said;The third phase winding end of the first represented respectively with D3 and D6.The six thrum import terminal connector,terminal marked accordingly D1~D6 tag,as shown in figure (1).Six of the three-phase stator winding end three-phase stator windings can be A star or triangle,y connection is to the end of the three-phase winding up magnet prices in parallel,the D4,D5,D6 three terminal with copper link together,and the three-phase winding head end access three-phase ac power supply respectively,the D1,D2,D3,respectively connected to A,B,C phase power source,as shown in figure 

(2).And triangle by law is the first end of the first phase winding to the 1 D connected to the end of the third phase winding D6,access to another phase power;Head end of the second phase winding connected to the end of the first phase winding D4 D2,and access to the second phase power;Head end of the third phase winding D3 connected to the end of the second rotor and stator phase winding D5,and access to the third phase power supply.Admiral in the patch panel terminal and D6 D1,D2 and D4,D3,and D5 connect with copper,then access to the three-phase power supply respectively,as shown in figure (3).An electric motive is pick a star or triangular,should depends on factory rules,available from the motor nameplate.Is the first of the three phase stator winding end manufacturers set beforehand,in no case can be generator parts stator arbitrary upside down,but the first end of the three-phase winding can be conversed together,such as the end of the three-phase winding D4,D5,D6 upside down as the head end,D1,D2 and D3 as an end,but never separate the ends of the head of a phase winding upside down,otherwise will produce wrong wiring.If wrong wiring junction box found raw,or winding end of the first mistake,light can't the normal starting motor,electric cause starting current is too large for a long time,motor heating is serious,affect the life,or burning motor winding,short circuit or power.

High voltage motor stator coil damage problem Electrical engineers

General electrical engineer pointed out that the long-term operating experience and motor stator winding accident phenomenon indicates that the generator and high voltage motor stator coil corrosion damage phenomenon is quite common,seriously affect the safe operation and service life of the motor.A,corrosion characteristics and parts of motor stator coil From the high voltage motor stator winding coil main insulation breakdown phenomenon,the main coil corrosion damage of the insulation can be roughly divided into two classes: class starts to coil outside the main insulation inner corrosion damage,often referred to as corrosion;Another kind began to coil internal insulation outside corrosion,commonly referred to as internal corrosion.1.1 main coil insulation outside corrosion damage (1) motor stator winding end inside the stator core and coil vibration,the primary coil insulation corrosion damage.This is the most common corrosion damage accident is also one of the most serious phenomenon.Cause this is the main reason of the corrosion damage,the motor in operation,because of its department of winding vibration under the action of electromagnetic force,the coil in the stator core groove end fixed not firm,article slot wedge,the line between layers of cushion,loose end interval block and tied the rope off,coil and lashing and friction within the interval between block,anticorona lacquer semiconductor corona corrosion damage,resulting in slot and end coil main insulation breakdown.

(2) the stator core wear corrosion of the internal magnetic materials.This kind of situation is mainly due to the maintenance process without careful cleaning and purging of the stator winding,causing the windings cracks and other corner place left some tiny magnetic sundry,when the motor running magnetic debris was adsorbed on the surface coil insulation Lord,under the action of electromagnetic induction and electromagnetic force,magnetic impurities in rotation movement,grinding main coil insulation to drill a hole.(3) of the stator coil corrosion of oil.At present,a large generator and high voltage motor bearing shell are widespread leak phenomenon,thus the motor coil for burning oil corrosion accidents are quite common.Parts of the basic focus of this kind of failure at the end of motor stator slot,winding and winding nose leads.Are attached to the coil is characterized by the oil,to dissolve erosion effect to the main coil insulation,main insulation and conductor is layered whole coil insulation strength is reduced,after long time running and stator winding short circuit,grounding short circuit fault,etc.(4) the stator core silicon steel sheet of corrosion wear of the insulation.If in the process of being connected in the stator iron core,silicon steel sheet laminated,irregular or stator core ventilation channel and the end pressure refers to fixed installation,or damage to the stator core in the repair,will cause the vibration occurs when the motor running,wear insulating,eventually resulted in the breakdown of the main insulation of wire coil.

1.2 coil corrosion Multiple accident statistics and fault coil autopsy results show that the coil internal corrosion is more serious.Corrosion inside the large coil anatomic analysis showed that the corrosion is generally from insulation and conductors in the air gap between the air bubbles,coil straight line and the end of the R Angle,coil lead off line welding etc.Corrosion phenomena within the first coil internal insulation to bleach and gradually expand,then burning insulation form hole and a large number of green powder,so as to accelerate and main corrosion damage of the insulation between wire strands,until the main insulation breakdown.In addition,the high temperature caused by the thermal aging is also an important factor to the internal corrosion.Second,the coil reason analysis of internal and external corrosion Motor stator coil of the internal and external corrosion reasons,mainly due to the main coil insulation in the motor running,long-term in electromagnetic vibration,high temperature and high voltage under the action of three kinds of factors and vibration wear,corona corrosion and thermal insulation aging,make whole coil insulation shell,layered,burning,wear and dielectric strength reduce wait for a phenomenon,resulting in insulation breakdown of failure.

Electromagnetic vibration wear corrosion (see electrical engineer) In the operation of the motor in produce all kinds of mechanical vibration,wear out coil insulation,corrosion is one of the main electromagnetic vibration on the motor end winding and the influence of notches.If the stator core installation quality is bad,bad winding end binding process,make the coil in the groove by fixed bad,produce great vibration amplitude,article water pump interlayer pad and temperature measuring element pads in the lower level to HuiCuan move between coil and wear on the lower layer coil,the coil main insulation damage.Is more serious is that,if in the operation of the coil wire through the current 2 times frequency electromagnetic vibration,will not only make the coil and iron core and winding end interval block vibration,make the main insulation surface wear,but also can make the wire with the main insulation between the friction between interturn,shares of the wire vibration,causing wire interturn,loose,short circuit,break between the shares.At the same time,the additional loss and the temperature rise in short circuit,will accelerate local main insulation ageing,reduce the dielectric strength,even under normal working voltage insulation breakdown caused by failure.Therefore,the electromagnetic vibration is caused by coil outside the main insulation 8500w gasoline generator corrosion and the main cause of the corrosion damage.