Four-axle aircraft does not have the implementation that brushs dc machine drive to control a design

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  • source:GAENOR CNC Machining
Four-axle aircraft is to be in of late the technical product with major and blame major very hot field. This article is aimed at four-axle aircraft below do not have the drive that brushs dc machine to control without positional sensor, the design developed three-phase circuit of drive of 6 arms complete bridge and control program. The design uses ATMEGA16 sheet piece machine regard control as core, use turn over electromotive force to detected at 0 o'clock too guide 6 MOSFET that connect drive circuit realize inverting; dc to not have by turns brush electric machinery to control a program to finish MOSFET electrify self check, electric machinery to start software to control, control of rotate speed of PWM electric machinery and circuit protect a function. Structure of this design circuit is simple, accident of low, report stabilizes cost all right reliable, realized electric machinery to run continuously. In recent years, four-axle is aero research and applied limits escalate, it uses 4 to not have brush dc machine to regard its as dynamical source. Without brush dc machine to be external rotor structure, high speed of direct drive airscrew rotates. Without the drive control means that brushs mainstream electric machinery main component is have positional sensor and the control kind that do not have positional sensor two kinds. Because the requirement in four-axle aircraft is not had,brush bulk of requirement of dc machine controller small, weight is efficient and light, reliable, use those who do not have positional sensor to not have consequently brush dc machine. What the article uses is Lang Yu X2212 Kv980 is not had brush dc machine. Without brush dc machine drive to control a system to include drive circuit and systematic programme controll two parts. The switch character that uses power pipe makes circuit of drive of three-phase complete bridge, DSP is used to regard as later advocate dominate chip, its powerful operation handles have the aid of ability, realize electric machinery start with control, but circuit structure is complex cost is high, devoid economy. Dc is used without the inverting that brushs electric machinery turn over electromotive force to pass 0 detect law, once detect to three-phase turn over electromotive force to prepared for inverting at 0 o'clock too. Turn over electromotive force to pass 0 detect the method that uses fictitious and neutral site, through detecting electric machinery of each photograph turn over electromotive force to judged rotor place too at 0 o'clock. And the inverting of electric machinery electric current that is based on winding of electric machinery three-phase to carry voltage change law is academic, can raise a system to control precision greatly. The article uses three-phase without the drive circuit that brushs dc machine circuit of 6 arms complete bridge, the administrative control chip that dominates circuit uses ATmega 16 sheet piece machine implementation, with developing its high-powered, resourceful characteristic adequately, periphery circuit structure is consequently simple. Without brush dc machine to use software to start with means of PWM speed pilot, realize electric machinery start and stability moves, raise four-axle aircraft not to have the timing that brushs dc machine and control function greatly. Circuit of drive of 6 arms complete bridge does not have 1 three-phase brush dc machine drive to if the graph is shown 1 times,dominate circuit. This circuit uses three-phase means of drive of 6 arms complete bridge, use this means to be able to reduce electric current wave motion and torsion are pulsatile, the torsion that makes electric machinery output bigger. Effect of 6 power field is used to be in charge of control to output voltage in part of electric machinery drive, the dc in four-axle aircraft is not had brush voltage of power source of circuit of electric machinery drive to be 12 V.

In drive circuit, q1~Q3 uses the) of IRFR5305(P raceway groove of IR company, q4~Q6 is) of IRFR1205(N raceway groove. Diode of follow on current hides inside this effect canal, voltaic access is provided when for field effect the canal closes, in order to prevent the retrorse breakdown of pipe, parameter of its model character sees a table 1.

T1~T3 uses PDTC143ET to provide drive signal for field effect canal. Express 1 MOSFET to be in charge of parameter by the graph 1 knowable, a1~A3 provides signal of drive of grid of arm of the bridge on three-phase complete bridge, as odd as ATMEGA16 the signal of hardware PWM drive of a machine is conterminous, pass those who change PWM signal to occupy empty Bilaishi to show electric machinery rotate speed to control;B1~B3 to provide signal of drive of grid of arm playing the bridge, by sheet piece the I/O mouth of machine is offerred directly, have guide with end two kinds of condition. Graph 1 without brush dc machine three-phase circuit of drive of 6 arms complete bridge is not had brush control of dc machine drive to use three-phase 6 state control is politic, power canal has 6 kinds to spark condition, every time only two pipe guide, inverting of angle of report of every 60 ° , when if some engraves AB photograph to guide temporarily,be being connected, c photograph up to, without voltaic output. Odd a position of electric machinery rotor that machine basis detects, the switch that uses MOSFET is characteristic, realize the electrify of electric machinery to control, for example, when Q1, Q5 is opened, AB photograph guides, right now voltaic flow direction is negative pole of power source of → of Q5 of → of B of winding of → of A of winding of → of Q1 of → of power source anode. Similar, open order to be Q1Q5 respectively when MOSFET, q1Q6, q2Q6, q2Q4, q3Q4, when Q3Q5, want to undertake accurate inverting in equal opportunity only, can come true to run continuously without what brush dc machine. 2 turn over electromotive force to pass 0 detect without brush dc function to run continuously normally quite, be about to undertake detecting to rotor position, realize accurate inverting thereby. Position of electric machinery rotor detects means basically has photoelectricity to code dish, Huo Er sensor, without feeling measure 3 kinds of way.

Because four-axle aircraft is not had,brush dc confidential to demand construction of system simple, weight is light, use the means that does not have positional sensor consequently, the n/ele be induced by electromotive force that uses three-phase generation passes at 0 o'clock hour defer 30 ° inverting. Although this method compares a trouble when electric machinery is started, can accuse sexual difference, but as a result of circuit simple, cost is low, agree with not to need the four-axle aircraft electric machinery that starts often in normal flight process consequently. Because do not have the two-phase that brushs dc machine to guide,know pattern, can use consequently do not guide the three-phase that connect detects the size that opposes electromotive force. If pursue 2 turn over electromotive force to detect circuit, neutral site N and odd an AIN0 of machine is conterminous, ain, bin, cin accepts the order respectively the ADC0 of a machine, ADC1, ADC2.

Keep comparing neuter to nod N voltage and A, b, c three-phase the size of voltage of 3 end points, give every n/ele be induced by electromotive force in order to detect over- at 0 o'clock. ATMEGA16 is odd of a machine imitate comparator be AIN0 to input end, lose to the input end configuration according to ADMUX register choice ADC0, ADC1, ADC2, used sheet thereby piece machine of the imitate comparator that takes oneself answer with the function. When A, during B photograph electrify, c contrary electromotive force and neutral site N undertake comparative, similar, can detect successfully give each look cross 0 incident. Graph 2 turn over electromotive force to detect of circuit electric machinery turn over electromotive force to detect after coming out, can find those who oppose electromotive force to pass at 0 o'clock, in turn over electromotive force to pass 0 hind angle of 30 ° report has delay inverting operation. 3 control programming 3.

Self check of electrify of circuit of 1 drive control is not had brush dc machine drive to control a part to include MOSFET self check, electric machinery to start control and voltage electric current to monitor a function 3 parts. The flow of electrify self check of drive control circuit is shown 3 times like the graph, include MOSFET short circuit character and guide a characteristic test, shed attaint circuit in order to had prevented. Graph flow chart of self check of electrify of circuit of 3 drive control 3.

2 software start control to turn over electromotive force to detect the law is in only the ability after electric machinery runs normally undertakes, do not turn when electric machinery or when rotate speed is very low, its turn over electromotive force to cannot detect, use the means that software starts consequently. In the light of control without what brush dc machine without positional sensor, the article uses the method that 3 paces start, above all, give A, b photograph electrify period of time in order to secure; of position of electric machinery rotor 6 condition by turns inverting, weld time reduces; to detect stage by stage of three-phase oppose electromotive force, if start a success normally, start afresh otherwise. The specific flow that start is shown 4 times like the graph. Graph 4 without brush start technological process without feeling dc electric machinery 3.

Function of aero system protection includes four-axle of design of function of 3 systems protection voltage, electric current monitors a function. Batteries voltage monitors functional circuit: Press voltage drop of circuit general batteries to sheet through simple cent piece inside the input range that machine A/D changeover permits (0~5 V) , monitor the electric machinery when preventing voltage to be not worth to stop through voltage turn; electric current detects functional circuit: Through 0.

Electric current of sampling of resistor of 01 Ω , translate into voltage, send sheet piece the A/D of machine changes a mouth, when malfunctioning in order to prevent, big electric current damages circuit. When electric current is monitored, use means of simple wave of numeric and average filter, the influence of electric current of abate instantaneous peak value to measuring an outcome. The article realizes 4 epilogue aero dc does not have four-axle the drive circuit that brushs electric machinery and programming of systematic control software. Drive circuit uses three-phase circuit of 6 arms complete bridge, MOSFET regards switch as component, use ATmega 16 sheet piece machine regard control as chip, turn over electromotive force to pass 0 detect and the control way that software starts, and 30 ° have delay inverting. After be being started normally, odd implementation does not have a machine output PWM brush dc engine rotate speed to adjust. Designed voltage, electric current to monitor circuit at the same time, make sure the system is safe, consequently, this system can normal drive is not had without positional sensor brush dc machine, and can apply at four-axle aircraft. CNC Milling CNC Machining