稳压电源中英文翻译.doc

1、英文原文 NC switching power supplyAbstractThis system based on 51 SCM control unit, used for LM2576-wild numerical control a switching power supply of fuzzy digital control technology, adjust load R1, R2 proportion to change occupies empties compared to make the output stability, and can be through the

2、buttons, digital display to realize output voltage numerical control. In addition, the system to input pressure, flow, input output flow, switch tube overheat as well as the protection circuit, ensure that the system is stable and reliable. Key words: the numerical control switch power supply，LM2576

3、-wild，microcontroller 1CONTENTSThe first chapter design task 1. Basic requirements 2. Play a part The second chapter overall scheme comparison and compared In the third chapter of the system hardware design (a) The design of the whole system 1. The system design thought 2. The block diagram of the w

4、hole system (b) Unit circuit function and the analysis of the operation 1. Minimum AT89S52 SCM system 2. Rectifier circuit 3. The power circuit 4. LM2576-A DJ voltage circuit 5. The whole wave output rectifier circuit parameters are calculated 6. Over-voltage protection The fourth chapter system sof

5、tware design 1. The flow chart of the whole system Chapter 5 system commissioning 1. The software debugging 2. Hardware debugging 3. The machine commissioning Chapter 6 system tests 1. The test project circuit 2. Testing instruments 3. Test results12The first chapter tasks and requirements(a) The ta

6、sk Design and construction of a switching power supply, its structure diagram shown as shown in figure 1 (b) Requirements 1, basic requirements (1) Basic specifications: input voltage: + 10 V/DC (fluctuating range 8 to 12 V) Output voltage: + 2.5 V/DC + 6.5 V/DC (2)The basic technical index: The out

7、put of subsection power shift, and 8 from + 2.5 V to 6.5 V +, and every 0.5 V increase. Namely (2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6) Efficiency: 70% (p + 2.5 V/DC, 1 A testing accurate) Maximum output current: 2 A; Voltage adjustment rate: 2% or less; Current adjust rate: 2% or less (3) Can be arbitrary

8、tuned to the requirements of the output voltage, and with a certain way of the display. (4) can be arbitrary through the keyboard control open/close the output voltage. 2. Play a part (1)Have over-voltage protection, input voltage protection movement, there are 15 V over current protection, more tha

9、n 3 A output current protection movement (2) Improve efficiency: 80% (p circuit to + 2.5 V/DC, 2 A testing accurate) (3)The ripple: 1% or less (+ 2.5 V/DC, 2 A 20 MHz oscilloscope testing accurate) (4) Press from low to high or from high to low order automatically change the output voltage, each fil

10、e 2 3 seconds, between time and space in the test.The second chapter scheme comparison and selectionPlan 1: the division components, such as Self-excitation switching power supply, the circuit principle diagram is as follows: The input voltage for AC220v, 50 Hz ac alternating current, after filterin

11、g, again by rectifier bridge after rectifying into a dc, through the control circuit switch tube conduction and globe make high frequency transformer of a low voltage measurement produce high-frequency voltage, small power by high-frequency transformer coupling to second test, then through rectifier

12、 filter, get dc voltage output. In order to make the output voltage stability, with the TL431 sampling error, the optical coupling amplifier, through the PWM to control switch tube conduction and deadline (i.e. occupies empties compared), makes the output voltage remain stable. From the foregoing, t

13、his scheme circuit is more complex, difficult, so dont debugging feasible. Plan2：DC-DC transform the BUCK type with A/D converter, and constantly testing power output voltage, depending on the power supply output voltage and of the difference of the set value, use of PWM module PWM waves in output,

14、direct control of the power supply. ARM extended buttons, digital display to realize the numerical control output voltage. This scheme is simple, but all the circuit by division components, interference; And PWM module single-chip microcomputer control program is complicated, consider 52 and A/D pro

15、gram between factors, will cause the output of the PWM delay, distortion, so that the output voltage is not quite stable, and so on. Plan 3: the special chip power LM2576-such as wild, its typical circuit are as follows: LM2576 series of stabilizer which are monolithic integrated circuit, can provid

16、e the buck switching voltage regulators (buck) all sorts of functions, can drive 3 A load, have excellent linear and load adjustment ability, and LM2576 stabilizer interior contains frequency compensation device and A fixed frequency as its, the number of the external components can be minimized, an

17、d easy to use. This scheme, 220 V / 50 Hz ac voltage after rectifying circuit and DC/DC voltage chip LM2576 wild transformation for stable-DC voltage, and then through the adjustment of the relationship of scale and R2 R1 to adjust LM2576 chip of the input output voltage stability than empty. An ext

18、ernal circuit components number less, and the program is simple, and the output voltage stability is good. Through various program, feasibility, complexity, system index comparative advantages and disadvantages of each scheme, comprehensive, we use the third plan.In the third chapter of the system h

19、ardware design(a)The design of the whole system 1. The design thought System to monolithic integrated circuit AT89S52, LM2576-for the core part, and the wild through the monolithic integrated circuit to output voltage gather, comparison, operations, and the output voltage control, automatic regulati

20、on system structure diagram shown as shown in figure 1. 220 V / 50 Hz ac voltage after rectifying circuit and DC/DC voltage chip LM2576 wild transformation for stable-5 12 V DC voltage output, the output voltage through sampling circuit by sampling, A/D conversion chip ADC0804 after converting to 52

21、 after processing, control simulation electron switch to choose 4051 respectively the nine potentiometer R2, change R1 and R2 ratio values, which change LM2576-of the wild chip PWM pulse of empty, MOS tubes work than to switch state in, the input of 15 V DC voltage chopped for the and of the same fr

22、equency PWM waves pulse wave, pulse wave through the rectifier filter circuit output for 5 12 V DC voltage. Because of this the topic request have nine output stepping demand, so can tune in advance each voltage resistance, through the corresponding key choice output voltage, directly to the analog

23、switch 4067 choose resistance, they can get to output voltage. At the same time, to detect the voltage, current value through the display LCD1062 real-time display. If working current is too big, the flow detection circuit will be sent to the testing results of single-chip microcomputer, SCM control

24、 relay through the ac branch realize over-current protection system in fault, after the operation is set by the reset button to may cause the system to resume normal work. 2. The block diagram of the whole system (b) Unit circuit function and the analysis of the operation 1. Minimum AT89S52 SCM syst

25、em Minimum system including crystal oscillator circuit and reset switch and power supply parts. Figure 2 for the minimum AT89S52 SCM system. 2. Rectifier circuit.The wave rectifier circuit is made up of two half wave of rectifier circuit. Because in the next two, add on miens input voltage of the op

26、posite polarity, therefore, to a dynamic balance, in every signal cycle, the C1 and C2 experience 2 times charger, discharge process, current will appear two current pulse with polarity. So in addition to the Vo saw tooth wave on the wavy frequency, improve the ability of double filtering, thus redu

27、ce ripple voltage.3.Power supply circuit The dc power by power supply, filtering, protection, such as voltage, four basic modules. (1)The power transformer USES a step-down transformer, the power grid voltage 220 V transform into need ac voltage. The ac voltage After rectifying, may obtain electroni

28、c equipment need dc voltage. (2) Use rectifier circuit bridge rectifier circuit single-phase, 50 Hz ac alternating current transformation for direction invariable but still has the pulse size straight Flow electricity. Its advantage is high voltage ripple voltage, small, the utilization rate of tran

29、sformer high. This design by A bridge pile of bridge rectifier, RS808 do maximum current can reach 8 A, cooperate with the design of the large filter capacitance, so the power of the instantaneous large current power supply characteristics, low noise, good reaction speed, output ripple small. （3） Fi

30、lter circuit using capacitance filter circuit, will the pulsation of the rectifier circuit output filter, get most of the components is smooth dc the electricity. This circuit adopts 4700 u F / 50 V large capacitance C3, C4 to make the output voltage more smooth, the power supply characteristics mom

31、ent, suitable for take the perceptual load, such as motor start-up. C3, C4 every parallel connection a 0.1 u F / 63 V CBB capacitance, filter to high frequency interference, make input to integrated circuits L11, L12 of dc as far as possible the smooth and pure. （4） By LM317 output voltage circuit i

32、s power, LM337 output negative supply. LM317 and LM337 are used internal heat Load, contains over current protection, hot off and safety working area for perfect protection circuit, that power can save the fuse, and so easy loss device. Regulating circuit: to meet the needs of the different applicat

33、ion situation and the voltage is set to can be adjusted. The calculation of the output voltage Vo = 1.25 x (1 + Rf/R), adjustable resistance in use precision can be resistor and guarantee the precise output voltage can be adjusted. If this article chooses for 5 k of Rf , R for 270 combination, can r

34、espectively on 1.25 V 24 V 1.25 V 24 V achieve continuous adjustable between. （5） Protection circuit for linear power supply heat, so the power larger add enough radiator. Due to the high performance integrated circuit, which can simplify the circuit structure, highlighting the important part in the

35、 power transformation. Through the commissioning and testing, good performance. The whole circuit The power not only can be used alone, also can be in other electronic equipment used in voltage or current stabilization source use. 4. LM2576-voltage circuit wild Working principle: Assume that the swi

36、tch transistors, diodes are ideal components, inductance and capacitance is ideal components, the output voltage ripple voltage output voltage and the ratio of the small to allow oversight. According to the current cycle to begin in IL inductance is starting from scratch, can be divided into current

37、 continuous working mode and inductance inductive current is discontinuous work patterns. Due to the continuous work mode inductance current converter, have very good control characteristic; Inductive current is discontinuous work mode, put the electric, inductance and capacitance easy to produce th

38、e oscillation, thus affecting the output voltage ripple; And the same occupies empties compared, output voltage in discrete model under the mode of work than the big, high efficiency. To sum up, the most ideal situation is in critical condition, stabilizer which work so we use two kinds of methods:

39、(1)The increase of the inductance inductive energy storage, increase, and extend the discharge of time (2)Improve the work and reduce the frequency switch time Make transistor in current continuous state. 5. The whole wave output rectifier circuit parameter analysis Output filter by free-wheeling di

40、ode rectifier circuit, inductance and capacitance composition. Consider free-wheeling diode in tube by PMOS transistor conduction, when energy consumption, and work in the state, so we used the low power consumption, high current, high-speed Scotty diodes IN5817, the characteristics as follows: Maxi

41、mum peak reverse voltage: 40 V The biggest reverse RMS voltage: 28 V The biggest dc voltage: 40 V block The biggest positive average rectifier current: 1 A The biggest positive pressure drop: 0.6 V (1 A) BUCK converter principle by analysis shows that in order to make work in inductive current circu

42、it continuous mode, and the ripple voltage So as far as possible, should be made great inductance we choose for 8 mH inductance Capacitors mainly is the absorb ripple with a smooth, the role of the voltage waveform. Capacitance and inductance is equivalent to a low pass filtering filter, the cut-off

43、 frequency defined asConsidering the capacitance equivalent series resistance losses, we choose the capacitance for 1000 uF. At this time the cut-off frequency of about 562 Hz ac, visible to dozens of kHz PWM waves have very good filtering effect. 6. Input over-voltage protection When the input volt

44、age in the normal range, the input sampling voltage comparator, less than the benchmark voltage output low level; When the input pressure, input voltage is greater than the benchmark sampling comparison output voltage, high level, ARM produce external interruption, warning, blockade, make PMOS trans

45、istor tube PWM signal, in order to protect the circuit damage. 7. Over-current protection Usually with hall current sensor detection of current directly PMOS transistor, and then with setting the Id threshold value, compared with comparison to control the output of the driver signal shut off; Or by

46、indirect method, the flow test voltage when the voltage drop the Vsd PMOS transistor, because the pressure drop contains short-circuit current information flow, when the Vsd increasing, and basically for linear relationship between the flow of testing, when the Vsd and with setting the threshold val

47、ue is used in the comparison, the comparator output control power circuit of the shutoff. 8. LCD display circuit Chapter 5 system commissioning1. The software debugging The design of the software is more simple, only the keys and LCD display two modules. Through the key control output voltage and th

48、e change of the commissioning, a began to discover that step is sometimes 0.5 v, sometimes become 1 v, then add the delay, eliminate buttons dither program can. 2. Hardware debugging First of all, points module debugging. First, then debugging power module LM2576-and 4067 wild voltage analog switch

49、module, first with high and low level directly elected 4067, using a millimeters to measure the output voltage is correct, after right in with 4067 single-chip microcomputer control, observation output voltage, with a screwdriver fine-tuning nine R2 resistance, change and a number of R2 R1 to adjust output voltage. Through these preliminary co