光伏系统中蓄电池的充电保护IC电路设计-毕业论文外文翻译

1、design of a lead-acid battery charging andprotecting ic in photovoltaic systemzeng dc-you，ling chao-dong5li guo-gang(yuanshun ic design r&d center, huaqiao university, quanzhou 362021, china)source: microelectronic device&technology.june 20071.introductionsolar energy as an inexhaustible, in

2、exhaustible source of energy more and more attention. solar power has become popular in many countries and regions, solar lighting has also been put into use in many cities in china. as a key part of the solar lighting, battery charging and protection is particularly important. sealed maintenance-fr

3、ee lead-acid battery has a sealed, leak-free, pollution-free, maintenancefiree, lowcost, reliable power supply during the entire life of the battery voltage is stable and no maintenance, the need for uninterrupted for the various types of has wide application in power electronic equipment, and porta

4、ble instrumentation. appropriate float voltage, in nonnal use (to prevent over-discharge, overcharge, over-current), maintenance-free lead-acid battery float life of up to 12 16 years float voltage deviation of 5% shorten the life of 1/2. thus, the charge has a major impact on this type of battery l

5、ife. photovoltaic, battery does not need regular maintenance, the correct charge and reasonable protection, can effectively extend battery lifb. charging and protection ic is the separation of the occupied area and the peripheral circuit complexity. currently, the market has not yet real, charged wi

6、th the protection function is integrated on a single chip for this problem, design a set of battery charging and protection functions in one ic is very necessary.2.system design and considerationsthe system mainly includes two parts: the battery charger module and the protection module of great sign

7、ificance for the battery as standby power use of the occasion, it can ensure that the external power supply to the battery-powered, but also in the battery overcharge, over-current and an external power supply is disconnected the battery is to put the state to provide protection, the charge and prot

8、ection rolled into one to make the circuit to simplify and reduce valuable product waste of resources figure 1 is a specific application of this ic in the photovoltaic power generation system, but also the source of this design.figure 1 photovoltaic circuit system block diagrammaintenance-free lead-

9、acid battery life is usually the cycle life and float life factors affecting the life of the batteiy charge rate, discharge rate, and float voltage. some manufacturers said that if the overcharge protection circuit, the charging rate can be achieved even more than 2c (c is the rated capacity of the

10、battery), battery manufocturers recommend charging rate of c/20 c/3. battery voltage and temperature, the temperature is increased by 1 °c, single cell battery voltage drops 4 mv, negative temperature coefficient of -4 mv / ° c means that the battery float voltage. ordinary charger for the

11、 best working condition at 25 °c; charge less than the ambient temperature of 0 °c; at 45 °c may shorten the battery life due to severe overcharge. to make the battery to extend the working life, have a certain understanding and analysis of the working status of the battery, in order

12、to achieve the purpose of protection of the battery. battery, there are four states: nonnal state, over-current state over the state of charge, over discharge state. however, due to the impact of the different discharge current over-capacity and lifetime of the battery is not the same, so the batter

13、y over discharge current detection should be treated separately when the battery is charging the state a long time, would severely reduce the capacity of the battery and shorten battery life. when the battery is the time of discharge status exceeds the allotted time, the battery, the battery voltage

14、 is too low may not be able to recharge, making the battery life is lower.based on the above, the charge on the life of maintenance-free lead-acid batteries have a significant impact, while the battery is always in good working condition, battery protection circuit must be able to detect the normal

15、working condition of the battery and make the action the battery can never normal working state back to normal operation, in order to achieve the protection of the battery.3. units modular design3lthe charging modulechip, charging module block diagram shown in figure 2. the circuitry includes curren

16、t limiting, current sensing comparator, reference voltage source, under-voltagedetection circuit, voltage sampling circuit and logic control circuit.figure2 charging module block diagramthe module contains a stand-alone limiting amplifier and voltage control circuit, it can control o伍chip drive, 20

17、30 ma, provided by the drive output current can directly drive an external series of adjustment tube, so as to adjust the charger output voltage and current . voltage and current detection comparator detects the battery charge status, and control the state of the input signal of the logic circuit. w

18、hen the battery voltage or current is too low, the charge to start the comparator control the charging. appliances into the trickle charge state when the cut-off of the drive, the comparator can output about 20 ma into the trickle charge current. thus, when the battery short-circuit or reverse, the

19、charger can only charge a small current, to avoid damage to the battery charging cuitent is too large this module constitutes a charging circuit charging process is divided into two charging status: high-current constant-current charge state, high-voltage charge status and low-voltage constant volta

20、ge floating state. the charging process from the constant current charging status, the constant charging current of the charger output in this state. and the charger continuously monitors the voltage across the battery pack, the battery power has been restored to 70% to 90% of the released capacity

21、when the battery voltage reaches the switching voltage to charge conversion voltage vsam charger moves to the state of charge in this state, the charger output voltage is increased to overcharge pressure voc is due to the charger output voltage remains constant, so the charging current is acontinuou

22、s decline. current down to charge and suspend the current ioct, the battery capacity has reached 100% of rated capacity, the charger output voltage drops to a lower float voltage vf.3.2 protection modulechip block diagram of the internal protection circuit shown in figure 3. the circuit includes con

23、trol logic circuit, sampling circuit, overcharge detection circuit, over-discharge detection comparator, overcurrent detection comparator, load short-circuit detection circuit, level-shifting circuit and reference circuit (bgr).过放电检丽j v. j- y-电踣人过充电检需 t 比较h过注1检ffl 比亵n1-tifigurc3 block diagram of bat

24、tery protectionthis module constitutes a protection circuit shown in figure 4. under the chip supply voltage within the normal scope of work, and the vm pin voltage at the overcurrent detection voltage, the battery is in normal operation, the charge and discharge control of the chip high power end o

25、f the co and do are level, when the chip is in normal working mode. larger when the battery discharge current will cause voltage rise of the vm pin at the vm pin voltage at above the current detection voltage viov, then the battery is the current status, if this state to maintain the tiov overcurren

26、t delay time, the chip ban on battery discharge, then the charge to control the end of co is high, the discharge control side do is low, the chip is in the current mode, general in order to play on the battery safer and more reasonable protection, the chip will battery ovcr-dischargc current to take

27、 over the discharge current delay time protection. the general rule is that the over-discharge current is larger, over the shorter the discharge current delay time. above overcharge detection voltage, the chip supply voltage (vdd> vcu), the battery is in overcharge state, this state is to maintai

28、n the corresponding overcharge delay time tcu chip will be prohibited from charging the battery, then discharge control end do is high, and charging control terminal co is low, the chip is in charging mode. when the supply vol tage of the chip under the overdischarge detection voltage (vdd <vdl,)

29、9 then the battery is discharged state, this state remains the overdischarge delay time tdl chip will be prohibited to discharge the battery at this time the charge control side co is high, while the discharge control terminal do is low, the chip is in discharge mode.保护模块tsoo> o afigure4 protecti

30、on circuit application schematic diagram4. circuit designtwo charge protection module structure diagram, the circuit can be divided into four parts: the power detection circuit (under-voltage detection circuit), part of the bias circuit (sampling circuit, the reference circuit and bias circuit), the

31、 comparator (including the overcharge detection /overdischarge detection comparator, over-current detection and load short-circuit detection circuit) and the logic control part.this paper describes the under-voltage detection circuit (figure 5), and gives the bandgap reference circuit (figure 6).豊分畝

32、大n出电踣匸-ui i！働置电路电路'分压电路ifigure6 a reference power supply circuit diagrambattery charging, voltage stability is particularly important, undcrvoltagc, overvoltage protection is essential, therefore integrated overvoltage, undervoltage protection circuit inside the chip, to improve power supply rel

33、iability and security. and protection circuit design should be simple, practical, here designed a cmos process, the undervoltage protection circuit, this simple circuit structure, process and easy to implement and can be used as high-voltage power integrated circuits and other power protection circu

34、it.undervoltage protection circuit schematic shown in figure 5，a total of five components: the bias circuit, reference voltage, the voltage divider circuit, differential amplifier, the output circuit. the circuit supply voltage is 10v; the m09 ml, m2, ro is the offset portion of the circuit to provi

35、de bias to the post-stage circuit, the resistance, ro, determine the circuit's operating point, the mo, ml, m2 form a current mirror; r1 m14 is the feedback loop of the undervoltage signal; the rest of the m3, m4 and m5, m6, m7, m8, m9, mio, mil, m12, m13, m14, composed of four amplification com

36、parator; ml5, do, a reference voltage, the comparator input with the inverting input is fixed (v+), partial pressure of the resistance rl, r2, r3, the input to the inverting input of the comparator, when the normal working of the power supply voltage, the inverting terminal of the voltage detection

37、is lost to the inverting terminal voltage of the comparator is greater than v+. comparator output is low, m14 cutoff, feedback circuit does not work; undervoltage occurs, the voltage divider of rl, r2, r3, reaction is more sensitive, lost to the inverting input voltage is less than v when the resist

38、or divider, the comparator the output voltage is high, this signal will be m14 open, the voltage across r into m at both ends of the saturation voltage close to ov, thereby further driving down the rl> r2, the partial pressure of the output voltage, the formation of the undervoltage positive feed

39、back. output, undervoltage lockout, and plays a protective role.5. simulation results and analysisthe design of the circuit in csmc 0.6 pm in digital cmos process simulation and analysis of the circuit. in the overall simulation of the circuit, the main observation is that the protection module on t

40、he battery charge and discharge process by monitoring vdd potential and vm potential leaving chip co side and do-side changes accordingly. the simulation waveform diagram shown in figure 7, the overall protection module with the battery voltage changes from the usual mode conversion into overcharge

41、mode, and then return to normal working mode, and then into the discharge mode, and finally back to normal working mode. as the design in the early stages of the various parameters to be optimized, but to provide a preliminary simulation results.012345012345012345r/sfigure7 overvoltage and under-vol

42、tage protection circuit simulation waveform6. conclusiondesigned a set of battery charging and protection functions in one ic. this design not only can reduce the product, they can reduce the peripheral circuit components the circuit uses the low-power design this project is underway to design optim

43、ization stage, a complete simulation can not meet the requirements, but also need to optimize the design of each module circuit.光伏系统中蓄电池的充电保护ic电路设计曾德友，凌朝东，李国刚（华侨大学 元顺集成电路研发中心，福建泉州362021）来源：微电子器件与技术2007年第6期1. 引言太阳能作为一种取之不尽、用之不竭的能源越来越受到重视。太阳能发电已 经在很多国家和地区开始普及，太阳能照明也已经在我国很多城市开始投入使用。 作为太阳能照明的一个关键部分，蓄电池的

44、充电以及保护显得尤为重要。由于密 封免维护铅酸蓄电池具有密封好、无泄漏、无污染、免维护、价格低廉、供电可 靠，在电池的整个寿命期间电压稳定且不需要维护等优点，所以在各类需要不间 断供电的电子设备和便携式仪器仪表中有着广泛的应用。采用适当的浮充电压， 在止常使用（防止过放、过充、过流）时，免维护铅酸蓄电池的浮充寿命可达1216 年，如果浮充电压偏差5%则使用寿命缩短1/2。由此可见，充电方式对这类电 池的使用寿命有着重大的影响。由于在光伏发电中，蓄电池无需经常维护，因此 采用正确的充电方式并采用合理的保护方式，能有效延长蓄电池的使用寿命。传 统的充电和保护ic是分立的，占用而积大并且外围电路复杂

45、。fi前，市场上还 没有真正的将充电与保护功能集成于单一芯片。针对这个问题，设计一种集蓄电 池充电和保护功能于一身的ic是十分必要的。2. 系统设计与考虑系统主要包括两大部分:蓄电池充电模块和保护模块。这对于将蓄电池作为 备用电源使用的场合具有重要意义，它既可以保证外部电源给蓄电池供电，又可 以在蓄电池过充、过流以及外部电源断开蓄电池处于过放状态时提供保护，将充 电和保护功能集于一身使得电路简化，并且减少宝贵的而积资源浪费。图1是此 ic在光伏发电系统中的具体应用，也是此设计的来源。直流负栽图1光伏电路系统框图免维护铅酸蓄电池的寿命通常为循坏寿命和浮充寿命，影响蓄电池寿命的因 素有充电速率、放

46、电速率和浮充电压。某些厂家称如果有过充保护电路，充电率 可以达到其至超过2c（c为講电池的额定容量），但是电池厂商推荐的充电率是 c/20c/3。电池的电压与温度有关，温度每升高1°c,单格电池电压下降4mv, 也就是说电池的浮充电压有负的温度系数4 mv/°co普通充电器在25°c处为最 佳工作状态；在环境温度为0°c时充电不足；在45°c时可能因严重过充电缩短电 池的使用寿命。要使得蓄电池延长工作寿命，对蒂电池的工作状态要有一定的了 解和分析，从而实现对蓄电池进行保护的目的。蓄电池有四种工作状态:通常状 态、过电流状态、过充电状态、过放电状

47、态。但是由于不同的过放电电流对蓄电 池的容量和寿命所产生的影响不尽相同，所以对蓄电池的过放电电流检测也要分 别对待。当屯池处于过充电状态的时间较长，则会严重降低电池的容量，缩短电 池的寿命。当电池处于过放电状态的时间超过规定时间，则电池由于电池电压过 低可能无法再充电使用，从而使得电池寿命降低。根据以上所述，充电方式对免维护铅酸蓄电池的寿命有很大影响，同时为了 使电池始终处于良好的工作状态，蓄电池保护电路必须能够对电池的非正常工作 状态进行检测，并作出动作以使电池能够从不正常的工作状态冋到通常工作状态, 从而实现对电池的保护。3. 单元模块设计3.1充电模块芯片的充电模块框图如图2所示。该电路

48、包括限流比较器、电流取样比较器、 基准电压源、欠压检测电路、电压取样电路和逻辑控制电路。图2充电模块框图该模块内含有独立的限流放大器和电压控制电路，它可以控制芯片外驱动器, 驱动器提供的输出电流为2030 ma,可直接驱动外部串联的调整管，从而调整 充电器的输出电压与电流。电压和电流检测比较器检测蓄电池的充电状态，并控制状态逻辑电路的输入信号。当电池电压或电流过低吋，充电启动比较器控制充 电。电器进入涓流充电状态，当驱动器截止时，该比较器述能输出20 ma左右， 进入涓流充电电流。这样，当电池短路或反接时，充电器只能以小电流充电，避 免了因充电电流过大而损坏电池。此模块构成的充电电路充电过程分

49、为二个充电 状态:大电流恒流充电状态、高电压过充电状态和低电压恒压浮充状态。充电过 程从大电流恒流充电状态开始，在这种状态下充电器输出恒定的充电电流。同时 充电器连续监控电池组的两端电压，当电池电压达到转换电压过充转换电压 vsam吋，电池的电量己恢复到放岀容量的70%90%,充电器转入过充屯状态。 在此状态下，充电器输岀电压升高到过充电压voc,由于充电器输岀电压保持恒 定不变，所以充电电流连续下降。当电流下降到过充中止电流ioct吋，电池的容 量己达到额定容量的100%,充电器输岀电压下降到较低的浮充电压vf。3. 2保护模块芯片内部保护电路模块框图如图3所示。该电路包括控制逻辑电路、取样电 路、过充电检测电路、过放电检测比较器、过电流检测比较器、负载短路检测电 路、电平转换电路和基准电路(bgr)oim»r>过放电检詣人过充电检丽 y 比较q cov 负v检测电踣°图3电池保护的系统框图此模块构成的保护电路如图4所示。当芯片的供电电压在正常工作范围内, 且vm管脚处的电压在过电流i检测电压之下，则此时电池处于通常工作状态, 芯片的充放电控制端co和do均为高电平，这吋芯片处于通常工作模