CN106505879B

CN106505879B - intelligent integrated power supply device of Internet of things

Info

Publication number: CN106505879B
Application number: CN201611176717.7A
Authority: CN
Inventors: 贺飞; 胡骅; 李跃
Original assignee: Jiangsu Ruibaote Technology Development Co Ltd
Current assignee: Jiangsu Ruibaote Technology Development Co Ltd
Priority date: 2016-12-19
Filing date: 2016-12-19
Publication date: 2019-12-10
Anticipated expiration: 2036-12-19
Also published as: CN106505879A

Abstract

The invention discloses an intelligent integrated power supply device of the Internet of things, which comprises a preposed public power supply module, a singlechip core control module, a direct-current voltage grade conversion module and a communication interface module; the prepositive public power supply module comprises an AC/DC prepositive basic voltage stabilizing circuit and an auxiliary power supply circuit; the singlechip core control module is used for collecting and monitoring the voltage and the current of each output module, programming and presetting the output voltage through a digital potentiometer and protecting each output circuit of the whole machine against overvoltage, overcurrent and overtemperature; the direct-current voltage grade conversion module comprises four identical modules, and each module comprises a DC/DC converter circuit, a current/voltage sampling circuit and a digital potentiometer; and the communication interface module is connected with the serial communication pin of the singlechip to complete the function of connecting with actual transmission interfaces in different forms, and forms network connection with a superior node to a monitoring center.

Description

Intelligent integrated power supply device of Internet of things

Technical Field

The invention relates to an intelligent integrated power supply device of the Internet of things, and belongs to the technical field of electronics.

Background

The street lamp has a lamp post and a public lighting power supply at the street, the lamp post and a lamp in the traditional concept are just used for public lighting at night, and the concept of a smart city big data system and an internet of things system is gradually put into practice and developed greatly, so people gradually realize that the urban public lighting system consisting of the lamp post, the lamp and a power supply network is the most potential infrastructure for the intelligent development of cities in the future and has incomparable resource advantages. The lamp pole and the lighting power supply network can also be conveniently derived with many additional functions outside the basic function of guarantee public lighting, for example, can bear the electric pile that fills of small-size electric automobile, can bear the information inquiry and bulletin system in city, the WIFI focus (realize the little basic station in city that WiFi covered), bear traffic and the video monitoring of public security, road vehicle flow statistics to and to PM2.5, PM10, carbon dioxide, ultraviolet ray, illuminance, humiture, atmospheric pressure, wind direction, wind-force, various environmental monitoring equipment of wind speed etc..

However, in the various independent systems, there are a large number of detectors, sensors and data transmission devices, so that it is inevitable to install an adaptive power supply for use with these devices to solve the power supply problem, which not only greatly increases the total number of components and occupies limited space, but also brings construction and maintenance difficulties due to the disordered discrete power supply and lead wires on each lamp pole, and is very easy to malfunction or even accident, and very unfavorable for safe operation.

In addition, another practical problem exists, namely in various and different systems, the requirements on the number, distribution density, even geographical position and environmental conditions of various front-end devices in the system are different, so that the types and the numbers of the internet of things devices arranged on the lamp posts are possibly inconsistent, and if the traditional direct-current voltage-stabilized power supply with a fixed voltage output type is still adopted for centralized power supply, the tidiness of the power supply types and specifications is difficult to realize, and the design, the purchase and the engineering application are not convenient.

Therefore, in order to solve the contradiction, an intelligent integrated power supply device of the internet of things (referred to as an intelligent integrated power supply device for short) specially designed for front-end equipment of the internet of things is urgently needed, so that the application range of lamp pole resources is further expanded, and a material foundation is laid for meeting the requirement of rapid development of smart cities in future.

Disclosure of Invention

The purpose is as follows: in order to overcome the defects in the prior art, the invention provides an intelligent integrated power supply device of the Internet of things, which is a power supply adapter which is based on a public lighting lamp pole, is arranged in the internal space of the lamp pole, shares the same commercial power supply resource with a lighting lamp and provides corresponding direct-current working power supplies for various front-end devices or equipment of the Internet of things.

The technical scheme is as follows: in order to solve the technical problems, the technical scheme adopted by the invention is as follows:

the utility model provides a thing networking intelligent integrated power supply device which characterized in that: the system comprises a preposed public power supply module, a singlechip core control module, a direct-current voltage grade conversion module and a communication interface module;

the prepositive public power supply module comprises an AC/DC prepositive basic voltage stabilizing circuit and an auxiliary power supply circuit; wherein, the leading basic voltage regulator circuit of AC/DC is a complete single-stage PFC flyback switching inverter circuit, includes: the system comprises incoming line filtering, full-wave rectification, a single-stage PFC flyback switch, a high-frequency isolation transformer and secondary rectification filtering, and is used for finishing the functions of power supply anti-interference, power factor compensation, AC-DC isolation conversion and direct-current voltage stabilization output; the auxiliary power supply circuit adopts a DC-DC switch conversion mode to further convert the +24V power supply stably output by the AC/DC preposed basic voltage stabilizing circuit into a stable +3.3V and +5V power supply for a singlechip core control module and a communication interface module;

The core control module of the single chip microcomputer adopts a universal single chip microcomputer with multiple I/O interfaces to complete the voltage and current acquisition and monitoring of each output module, and realizes the programming presetting of output voltage and the overvoltage, overcurrent and overtemperature protection functions of each output circuit of the whole machine through a digital potentiometer;

The direct-current voltage grade conversion module comprises four completely same modules, although the output voltage can be flexibly adjusted, the module structures are completely consistent, and each module comprises a DC/DC converter circuit, a current/voltage sampling circuit and a digital potentiometer; for performing: converting a +24V direct-current power supply sent by a front public power supply module into output direct-current power supplies with different voltage levels; receiving an adjusting instruction sent by the singlechip through a group of control buses, and realizing adjustment control on the output direct-current voltage of the module through the operation of a digital potentiometer, wherein the digital potentiometer is formed by cascading two potentiometers with different resistance levels; the precise voltage stabilization function of the output voltage of the module is realized through a voltage closed loop feedback circuit in a DC/DC converter circuit; a protection control signal is sent back to the singlechip through a current/voltage sampling circuit, so that the fault protection of the module is realized;

the communication interface module is connected with a serial communication pin of the singlechip to complete the function of connecting with actual transmission interfaces of various forms, and forms network connection with a superior node to a monitoring center.

Further, after the 220V alternating current mains supply is rectified, the AC/DC pre-basic voltage stabilizing circuit drives the inverter and the high-frequency isolation transformer to perform inversion, isolation and voltage reduction processing through the single-stage PFC switch control chip, and then the AC/DC pre-basic voltage stabilizing circuit becomes +24V direct current output through secondary rectification and filtering, and the direct current output is transmitted to a direct current power supply bus of a multi-output stage to provide input direct current power supply for each multi-output stage module of a rear stage; meanwhile, the auxiliary power supply circuit is provided with required direct current power supply so as to maintain the normal work of the whole set of device including the singlechip core control module.

furthermore, the power supply input end of the auxiliary power supply circuit is connected to a +24V direct-current output bus of the AC/DC preposed basic voltage stabilizing circuit, a +5V output voltage is obtained after the voltage stabilizing circuit passes through the non-isolated switch, the +5V output is divided into two paths, and one path becomes a +3.3V power supply after precise linear voltage stabilization and is used for supplying power to the core control module of the single chip microcomputer; and the other path still maintains +5V voltage after isolated DC/DC conversion and supplies power to the RS485 communication interface.

as a preferred scheme, the AC/DC prepositive basic voltage stabilizing circuit adopts an AC-DC working mode, single-path output is realized, and the capacity is 24V/2A and 50W; FT822 is selected as the integrated chip U1.

specifically, the AC/DC pre-basic voltage stabilizing circuit: alternating current commercial power is sent into a surge absorption and anti-interference filter circuit comprising a piezoresistor RV1, a capacitor C1, a common mode inductor L1, a capacitor C2, a C3 and a C4 through an interface JP1 and a fuse F1, then rectified into pulsating direct current through a full bridge BRG1, and sent to a power switch circuit for chopping processing;

An integrated chip U1 (FT 822) is a drive control part of a power switch tube, a +250V voltage at the output end of a rectifier bridge is connected to the working power supply input, namely the 8 th pin, of the U1 through resistors R4 and R5 to be used as an initial drive power supply at the starting moment (after normal work, the 8 th pin supplies power, namely, the alternating output of the secondary side of a step-down isolation transformer is subjected to secondary rectification by using a diode D5, and then stable direct current obtained after filtering by a capacitor C10 is used as a power supply); the integrated chip U1 needs to detect the amplitude of the input pulsating dc voltage, so its pin3 is connected to the voltage dividing point of the voltage divider formed by the resistors R1, R2 and R3; the integrated chip U1 needs to detect the zero-crossing time of the chopped wave signal after passing through the step-down isolation transformer, so the 5 th pin is connected to the connection point of the secondary coil of the transformer and the secondary rectifier tube D5; the integrated chip U1 needs to detect the working current of the power switch tube Q1, so the 4 th pin is connected to the upper end of a Q1 source current sampling resistor R10;

the integrated chip U1 needs to detect the deviation of the +24V output voltage from the standard value to make the closed-loop adjustment of the output voltage to keep it constant, so a voltage divider including resistors R17 and R18 is provided at the +24V output terminal, after comparing the sampled value with the reference value inside the chip Q2 and performing difference amplification by a high gain amplifier inside the chip Q2, the difference signal is passed through the light emitting diode of the photo coupler OPT1 in the form of current change to reflect the isolated corresponding difference signal on the secondary series resistor R14 of the photo coupler OPT1, and then the signal is sent to the 1 st pin of the integrated chip U1 through the resistor R7 to change the operating parameter of the U1, and a corresponding driving pulse is output from the 7 th pin and sent to the gate of the high power os switching tube Q1 through the resistor R8 to realize the closed-loop voltage stabilization control of the +24V output voltage.

preferably, in the DC voltage class conversion module, the DC/DC converter circuit employs an MP1593 chip, a PIN2 of the integrated circuit is a power input terminal, a PIN4 is a public ground terminal, a PIN7 is a chip operation enable terminal, a PIN3 is an output terminal of the internal power switch tube, a PIN1 is a bootstrap power supply terminal of the internal switch tube driving circuit, a PIN8 is a soft start time setting terminal, a PIN5 is an output feedback voltage input terminal, and a PIN6 is an input terminal of a compensation element of the internal error amplifier;

the power input end is directly connected to a +24V direct-current output bus of the AC/DC prepositive basic voltage stabilizing circuit through a socket; the common ground wire end is directly connected to a common ground wire, the PIN7 of the enable end is connected to a corresponding I/O PIN of the single chip microcomputer through a connecting wire of a label M1-MEN, and meanwhile, the PIN is grounded through a pull-down resistor R29 and an anti-interference capacitor C38; the PIN PIN3 at the output end of the switch tube has three paths connected to the outside: the main circuit is connected to the output end (labeled as M1-OUT +) of the module through an inductor L4, the second circuit is connected to a bootstrap power supply terminal PIN1 of an internal switching tube driving circuit through a capacitor C39 to provide a bootstrap signal for a driving tube, the third circuit is grounded through a freewheeling diode D16 to provide a freewheeling loop for an inductor L4 during the turn-off period of the internal switching tube; the PIN PIN8 is grounded through a timing capacitor C37 to determine the soft start time, and the compensation element access terminal PIN6 of the internal error amplifier is commonly grounded through a compensation capacitor C44 and a series combination circuit of C43 and R32 to stabilize the operation of the error amplifier; the output voltage feedback loop is obtained by a resistor divider, the upper arm of the resistor divider is a resistor R31, the lower arm of the resistor divider is formed by cascading two digital potentiometers U8 and U9, the voltage division point (the lower end of R31) of the resistor divider is connected to the input end of the output feedback voltage, sampling of the output voltage is realized, and then the comparison result of the sampling value and the reference value is dynamically adjusted through an internal error amplifier so as to stabilize the output voltage of the module;

After a power input end (PIN PIN 2) is powered by a front-stage +24V direct-current output bus through a socket, if TTL high level is added to a chip work enabling end (PIN PIN 7) under the control of a single chip microcomputer, an IC is started to enter a working state; after the on-time Ton, the internal power MOS transistor is turned on, so that the input voltage is output through the PIN3 end and is added to the left end of the inductor L4, the voltage is supplied to the external load of the module through a filter circuit formed by the inductor L4 and the capacitor C5, and magnetic field energy is stored in the inductor L4; after time Toff, the internal power MOS is turned off, and the reverse voltage generated across the energy storage inductor L4 is positive, negative, right, and left, so that the voltage applied across the freewheeling diode D16 is a forward bias voltage, which turns on the diode, and thus a discharge loop is formed between the inductor L4, the diode D16, and the external load, and the electric energy stored in the inductor L4 is discharged to the external load to provide the current required by the load.

as a preferred scheme, the singlechip core control module comprises a singlechip, and the singlechip is provided with a field debugging interface for realizing the adjustment and configuration of each output voltage on the field; the single chip is also provided with an industrial control bus type communication interface, exchanges data with an operation and maintenance center through a communication network, and sets output voltage parameters and the highest output current of each path in a remote control mode; an STM32F103C8 singlechip is adopted, a working power supply VCC is 3.3V, and 35 available I/O pins are arranged except a reset pin RST, crystal oscillator pins XO and XI, a standby power supply access pin VBAT and a BOOT0 pin, namely PA 0-PA 15, PB 0-PB 15 and PC 13-PC 15;

the specific allocation of the I/O pins is as follows:

1. Pin assigned to "RS 485 communication interface":

PA 0: (DE/RE \), the serial port receives and transmits the direction control signal (low receiving and high transmitting);

PA1 (PV), monitoring signals of a power supply of the serial port chip, wherein the signals are high when the serial port chip works;

PA2 (USART-TX), serial data transmitting end;

PA3 (USART-RX), serial port data receiving end;

2. pins assigned to the "field debug interface":

PA13 (SWDIO) debug data port line;

PA 14: (SWCLK) debug clock port lines;

3. and each direct current voltage grade conversion module is distributed for sampling output voltage and current (an analog input port of AD conversion is needed):

PA4, PA 5: the voltage and current sampling module is respectively used for converting the DC voltage grade into the voltage and current of the first module;

PA6, PA 7: the voltage and current sampling module is respectively used for converting the DC voltage grade into the voltage and current of the second module;

PA8, PA 9: voltage and current sampling respectively used for the DC voltage grade conversion third module;

PA10, PA 11: the voltage and current sampling module is respectively used for converting the DC voltage grade into the voltage and current of the fourth module;

4. each output module is distributed to carry out digital potentiometer control:

PA12, PB 0-PB 3: the DC/DC chip enable, the first potentiometer enable, the potentiometer stepping, the moving direction of a center head of the potentiometer and the second potentiometer enable in the first module are respectively used for DC voltage grade conversion in sequence;

PB 4-PB 8: the first potentiometer, the second potentiometer and the third potentiometer are sequentially used for DC/DC chip enabling, first potentiometer enabling, potentiometer stepping, potentiometer center head moving direction and second potentiometer enabling in the second module of DC voltage grade transformation respectively;

PB 9-PB 13: the DC/DC chip enable, the first potentiometer enable, the potentiometer stepping, the potentiometer center head moving direction and the second potentiometer enable in the third module are respectively used for DC voltage grade conversion in sequence;

PB 14-PB 15, PC 13-PC 15: the DC/DC chip enable, the first potentiometer enable, the potentiometer stepping, the potentiometer center head moving direction and the second potentiometer enable in the fourth module are respectively used for DC voltage grade conversion in sequence;

the adjustment of the voltage of the output module by controlling the digital potentiometer in each module by the singlechip can be briefly described as the following process: taking the first output module as an example, firstly inputting a required output voltage value into the single chip microcomputer through a field debugging interface or an RS485 communication interface, immediately acquiring the actual output voltage of the first output module by the single chip microcomputer through a PA4 port line, and if the actual output voltage meets the voltage configuration requirement, not processing the actual output voltage; if the voltage configuration requirement is not met, adjustment is needed.

When the output voltage needs to be increased, it indicates that the total resistance of the potentiometer serving as the lower arm of the voltage sampling voltage divider needs to be reduced, at this time, the single chip microcomputer firstly sets the port PB0 line (connected to the CS \ pin of the potentiometer U8) low and the port PB3 line (connected to the CS \ pin of the potentiometer U9) high, that is, only the potentiometer U8 is enabled, and enters a "coarse adjustment" process. As the resistance value needs to be reduced, the single chip microcomputer sets a PB2 port line (connected with a U/D \ pin) to be low, the selection of 'gear reduction' operation is indicated, a negative jump from high to low is output through a PB1 port line (connected with an INC \ pin), the high level is returned after the 1uS low level is maintained, a negative clock pulse is formed, and the resistance value between VL and VW is reduced by one gear under the synergistic action of an internal reversible counter, a decoder and a switch array. If negative clock pulse is continuously provided through the PB1 port line, the operation of resistance downshift is continuously carried out until the PB0 port line (connected with the CS \ pin of the U8 potentiometer) and the PB1 port line (connected with the INC \ pin) are both controlled by the single chip microcomputer to output high level, at the moment, the counter value is locked in the nonvolatile register, and the resistance value of the digital potentiometer is not changed any more.

if the output voltage needs to be reduced, the singlechip only needs to set the PB2 port line (a potentiometer U/D \ pin) high in the steps, and the operation of 'upshifting' is selected;

If the digital potentiometer U9 is needed to further fine-tune the output voltage, the single chip microcomputer only needs to set the PB0 port line (connected to the CS \ pin of the potentiometer U8) high and the PB3 port line (connected to the CS \ pin of the potentiometer U9) low, and the U9 is selected to be operated, and the application of other port lines is the same as that described above.

preferably, the communication interface module adopts an ADM2483 chip, is an isolated RS485 transceiver, and includes an RS485 transceiver and three single-channel optical couplers (having all isolation functions of three transmission channels).

has the advantages that: the intelligent integrated power supply device of the internet of things provided by the invention is supported by a public lighting lamp post, is arranged in the cylindrical inner space of the lamp post, shares the same commercial power supply resource with a lighting lamp, and is a power supply adapter for providing corresponding direct current working power supplies for various front-end devices or equipment of the internet of things, and has the following advantages:

Firstly, a circuit structure with one path of single-phase alternating current commercial power input and multiple paths of different voltage direct current output is adopted to meet the requirements of both a power supply side and a power transmission side. According to the research on a large number of power receiving devices and equipment, the required voltage level is generally between 5V and 24V, the required power capacity is generally between a few mW and a few W, and for example, the power consumption of temperature, humidity, ultraviolet and illumination sensors is generally between 25 mW and 30 mW; the power consumption of the PM2.5 sensor and the traffic flow sensor is about 0.6-3W, and the power consumption of equipment such as a wind sensor, a video monitoring probe and a WIFI hotspot is slightly larger and is about in the range of 6-12.5W. Therefore, the intelligent integrated power supply device is divided into four paths of direct current output according to the consideration that the total power output of each path is 50W, and the maximum output current of each path is 2A.

such structural style can concentrate on the one hand and utilize one set of commercial power inlet wire filter, solves the anti-interference problem of the feeder ear of four ways power output simultaneously, can adapt to the load of multiple different voltages under the prerequisite of guarantee filtering effect again, and can effectively reduce equipment volume to reduce components and parts cost.

Secondly, the current transformation circuit in the intelligent integrated power supply device adopts a two-stage working mode:

the front stage is a common AC-DC mode, after commercial power is rectified, the commercial power is subjected to voltage reduction isolation processing and secondary side rectification filtering through a flyback switch inverter circuit with single-stage PFC control and a high-frequency isolation transformer to form +24V direct current output to be sent to a direct current bus. The power factor of the device can be improved to more than 95% by adopting advanced flyback switch inversion with single-stage PFC control so as to meet the requirement of green energy specification;

the rear stage is in a DC-DC working mode, and converts the +24V direct current provided by the direct current bus into voltage output of the same level or lower level according to requirements. The four direct current outputs are in modular design, and modules of each path can be interchanged. The nominal output voltages of all the circuits can be configured according to nominal values of +5V, +12V and +24V, and can also be configured into various non-nominal voltage outputs according to special requirements. In order to reduce loss, the module efficiency adopted by the design is about 95%.

thirdly, in the intelligent integrated power supply device, in order to realize the flexibility of supplying power to various sensing or communication devices and to enable the output voltage to be configured flexibly on site or at a far end, an intelligent adjusting mode taking a single chip microcomputer as a core is adopted, on one hand, the single chip microcomputer is provided with a site debugging interface, the adjustment and configuration of the output voltage of each path can be conveniently realized on site, on the other hand, the single chip microcomputer is also provided with an industrial control bus type communication interface, the data exchange can be carried out with an operation and maintenance center through a network, and the output voltage parameters and the highest output current of each path can be directly set in a remote control mode.

fourthly, in the intelligent integrated power supply device, once the on-site or remote configuration of the output voltage is confirmed, the output voltage must be stable and reliable, and cannot be influenced by other processes of the single chip microcomputer or the program run-off fault caused by the interference of the single chip microcomputer. In order to achieve the purpose, a reliable hardware structure is required to be adopted for guarantee, except that a necessary configuration flow receives the instruction of the single chip microcomputer, a stable voltage feedback closed loop system is formed at other moments, the hardware of the closed loop system completely works independently, and each path of output is stabilized within a set range.

Fifthly, in order to realize the adjustable function of each output voltage, each output module of the intelligent integrated power supply device must have the isolation function of the output end, that is, when a certain voltage is adjusted, the electrical connection between the output and the load must be cut off at first, or the output of the output must be adjusted to zero, so as to avoid the influence or impact of the voltage change on the load equipment in the adjustment process. In order to achieve the purpose, the related circuit is required to have blind tuning performance, namely, the corresponding relation between the single chip microcomputer output regulation information and the controlled hardware reaction result is known, even if the output is temporarily cut off, the single chip microcomputer output regulation information can be adjusted to be within a small range near an expected value, and only fine tuning is needed after the output is switched on.

sixthly, at present, a plurality of communication modes can be selected by remote control, and the wired type comprises an RS485 industrial control bus, a Power Line Carrier (PLC) and the like; the wireless type has technologies such as Zegbee and LoRa networking, especially a newly developed LoRa networking technology, not only can be suitable for the configuration of the intelligent integrated power supply device and the transmission requirement of monitoring data, but also can provide a public data transmission channel for various Internet of things terminal acquisition monitoring devices, and further resource sharing is realized.

Seventh, in order to ensure the safety of the supplied power load devices and the safety of the supplied power load devices, the intelligent integrated power supply device must have perfect protection functions, including incoming line surge protection, overvoltage-overcurrent protection, output overvoltage-overcurrent protection, complete machine overtemperature protection and the like. The whole machine design has reasonable power allowance and has waterproof and dustproof characteristics according with national standards.

drawings

FIG. 1 is a block diagram of the system of the present invention;

FIG. 2 is a diagram of an AC/DC pre-basic voltage regulator circuit;

FIG. 3 is a circuit diagram of an auxiliary power supply;

FIG. 4 is a circuit diagram of a core control module of the single chip microcomputer;

FIG. 5 is a circuit diagram of a DC voltage level conversion module;

Fig. 6 is a circuit diagram of a communication interface module.

Detailed Description

The present invention will be further described with reference to the following examples.

as shown in fig. 1, the intelligent integrated power supply device of the internet of things provided by the invention is a power adapter which is based on a public lighting lamp pole, is installed in a hollow inner space of the lamp pole, shares the same commercial power supply resource with a lighting lamp, and provides corresponding direct current working power supply for various front-end devices or equipment of the internet of things, and specifically comprises four parts:

the first part is a prepositive public power supply module, which comprises an 'AC/DC prepositive basic voltage stabilizing circuit' and an auxiliary power supply circuit, as shown in figure 2, wherein the 'AC/DC prepositive basic voltage stabilizing circuit' is a complete single-stage PFC flyback switching regulator, and comprises: the power supply comprises parts such as incoming line filtering, full-wave rectification, a single-stage PFC flyback switch, a high-frequency isolation transformer, secondary rectification filtering and the like, and the functions of power supply anti-interference, power factor compensation, AC-DC isolation conversion, direct-current voltage stabilization output and the like are completed. As shown in fig. 3, the auxiliary power circuit further converts the +24V power stably output by the AC/DC pre-basic voltage regulator circuit into highly stable +5V and +3.3V power by using a DC-DC switching conversion mode, which is used by the communication part and the core control module of the single chip microcomputer.

Since this part is the first stage circuit in the present apparatus, it is hereinafter referred to as "front common power supply".

As shown in fig. 4, the second part is a core control module of a single chip microcomputer, and a general single chip microcomputer with multiple I/O interfaces is adopted to complete voltage and current acquisition and monitoring of each output module, and multiple protection functions such as programming presetting of output voltage, overvoltage, overcurrent, overtemperature and the like of each output circuit of the whole machine are realized through a digital potentiometer.

As shown in fig. 5, the third part is a DC voltage level conversion module, which has four identical modules, (DC/DC-1 to DC/DC-4), and each module can independently perform the following functions:

1. The +24V direct current power supply sent by the prepositive public power supply module is converted into output direct current power supplies with different voltage levels (more than two modules are allowed to be in the same voltage level).

and receiving an adjusting instruction sent by the singlechip through a group of control buses, and realizing the adjustment control of the output direct-current voltage of the module through the operation of the digital potentiometer.

3. the precise voltage stabilizing function of the output voltage of the module is realized through a voltage closed loop feedback circuit.

4. and a protection control signal is sent back to the singlechip through the current/voltage sampling circuit, so that the fault protection of the module is realized.

as shown in fig. 6, the fourth part is a communication interface module, which is connected to serial communication pins of the single chip to complete the function of connecting to actual transmission interfaces of various forms, and forms a network connection with a higher node to a monitoring center, so as to provide the intelligent integrated power supply device with remote centralized scheduling configuration and monitoring performance.

Examples

in fig. 2 and 3, the actual circuit configuration of the "AC/DC pre-base voltage stabilizing circuit" and the "auxiliary power supply circuit" is shown.

as shown in fig. 2, the "AC/DC pre-basic voltage stabilizing circuit" is a flyback switching inverter circuit with perfect incoming line filtering performance, and is used to rectify 220V AC mains supply, perform inversion, isolation and voltage reduction processing through an inverter device and a high-frequency isolation transformer driven by a switching control chip, and then convert the rectified AC mains supply into +24V DC output through secondary rectification and filtering, and send the DC output to a DC supply bus of a multi-output stage, so as to provide input DC supply for each multi-output stage module of a rear stage. Meanwhile, the auxiliary power supply circuit is provided with required direct current power supply so as to maintain the normal work of the whole set of device including the singlechip core control module. In the embodiment, the 'AC/DC pre-basic voltage stabilizing circuit' adopts a conventional AC-DC working mode, single-path output and 24V/2A (50W) of capacity. Due to the fact that FT822 is used as the integrated chip U1, compared with a traditional power supply chip, the power supply chip has better light load efficiency, and typical efficiency can reach about 90%.

As shown in fig. 3, a power supply input end of the auxiliary power supply circuit is connected to a +24V DC bus output by the AC/DC pre-basic voltage stabilizing circuit, a +5V output voltage is obtained through the high-efficiency non-isolated switch voltage stabilizing circuit, the +5V output is divided into two paths, and one path is subjected to precision linear voltage stabilization to form a +3.3V power supply for supplying power to the core control module of the single chip microcomputer; and the other path still maintains +5V voltage after isolated DC/DC conversion and supplies power to the RS485 communication interface. The working principle of this part of circuit basically belongs to the well-known mature power supply technology, so it is not described herein any more, and only the following circuit components are briefly described:

alternating current commercial power is sent into a surge absorption and anti-interference filter circuit formed by a piezoresistor RV1, a capacitor C1, a common mode inductor L1, a capacitor C2, a capacitor C3 and a capacitor C4 through an interface JP1 and a fuse F1, then rectified into pulsating direct current through a full bridge BRG1, and sent to a power switch circuit for chopping processing.

the integrated chip U1 (FT 822) is a driving control part of the power switching tube, and the +250V voltage at the output end of the rectifier bridge is connected to the working power input (8-pin) of the U1 through the resistors R4 and R5, and is used as an initial driving power at the moment of starting (after normal operation, the 8-pin power supply is obtained by performing secondary rectification on the alternating output of the secondary side of the step-down isolation transformer through the diode D5, and then filtering through the capacitor C10 to obtain a stable direct current as a power supply). The integrated chip U1 needs to detect the amplitude of the input pulsating dc voltage, so its pin3 is connected to the voltage dividing point of the voltage divider formed by the resistors R1, R2 and R3; the integrated chip U1 needs to detect the zero-crossing time of the chopped wave signal after passing through the step-down isolation transformer, so the 5 th pin is connected to the connection point of the secondary coil of the transformer and the secondary rectifier tube D5; the integrated chip U1 needs to detect the operating current of the power switch Q1, so its 4 th pin is connected to the upper end of the Q1 source current sampling resistor R10.

the integrated chip U1 also needs to detect the deviation of the +24V output voltage from the standard value, in order to make closed-loop adjustments to the output voltage to keep it constant, therefore, a voltage divider formed by resistors R17 and R18 is arranged at the +24V output end, and through comparison of a sampling value and an internal reference value (2.5V) of a chip Q2 (model TL 431), after differential amplification is performed by a high gain amplifier inside the Q2, the differential signal is passed through the light emitting diode of the photo coupler OPT1 in the form of current change, reflecting the corresponding difference signal isolated across the secondary series resistor R14 of the optocoupler OPT1, then the signal is sent to the No. 1 pin of the integrated chip U1 through a resistor R7 to change the operation parameters of U1, and the 7 th pin outputs corresponding driving pulse, and the driving pulse is sent to the grid electrode of a VMOS high-power switching tube Q1 through a resistor R8, so that closed-loop voltage stabilization control of +24V output voltage is realized.

Because the power frequency pulsating direct current peak value output by the rectifier bridge is higher, the overshoot voltage amplitude value near the peak value is higher, and in order to avoid the overshoot voltage near the peak value from damaging the power switch tube, an overshoot voltage absorption loop consisting of a resistor R11, a capacitor C6 and a diode D1 is arranged on the primary coil of the step-down isolation transformer.

the AC-DC conversion circuit also has the performance of PFC (active power factor compensation), because the filter capacitor C5 behind the rectifier bridge BPG1 is not a general high-capacity high-voltage electrolytic capacitor, but a CBB capacitor with small capacity, and can not effectively smooth the direct current pulse rectified at the power frequency of 50Hz, so that the direct current pulse component still remains unchanged basically, and under the combined action of a special switching chopping control chip and a subsequent feedback adjusting circuit, the chopping frequency at the position where the power frequency waveform peak appears is lowest, the chopping frequency at the zero-crossing point of the power frequency waveform is highest, and the chopping frequency in the middle process is changed in inverse proportion according to the sine rule along with the pulse amplitude. According to the basic principle of the PFC circuit, the current of the mains input end is forced to change along with the voltage of the input end, and the state of the current voltage waveform is kept basically consistent, so that the power factor of the incoming end is very high (reaching 95-98%), and the requirement of a single-stage PFC switching power supply is met.

the front-mounted public power supply module has high output voltage stability, and the output bus of the front-mounted public power supply module is used as a power supply loop of a subsequent multi-path direct current voltage grade conversion module, so that the stability of each path of output voltage is further ensured, and the requirements of reliable work of the internet of things terminal acquisition and detection equipment can be well met.

in fig. 4 to 6, circuit structures of an embodiment of the single chip microcomputer core control module, the dc voltage level conversion module and the communication interface module are shown.

a dc voltage level conversion module, as shown in fig. 5:

The core of the module is a step-down DC/DC converter module, the maximum output current is 2A, and the output voltage can be preset and set within the range of 5-24V through programming. Each dc voltage level conversion module has the same circuit structure and component values, and in fig. 5, only the actual structure of the module 1 (first path) is shown, and the other three paths are represented by boxes, which are labeled as module 2, module 3, and module 4.

1. circuit structure and basic function of DC/DC converter

The core of the DC/DC part is an MP1593 chip, and the typical efficiency is 95%. This integrated circuit's PIN PIN2 is power input end, PIN PIN4 is public ground terminal, PIN PIN7 is the chip work enable end, PIN PIN3 is the output of internal power switch tube, PIN PIN1 is internal switch tube drive circuit's bootstrap supply end, PIN PIN8 sets up the end for soft start time, PIN PIN5 is output feedback voltage input end, PIN PIN6 is internal error amplifier's compensating element incoming end.

As described above, in this embodiment, the operating power of the dc voltage level conversion module at the later stage is supplied by the "common power source" at the first stage, so the power input terminal (PIN 2) is directly connected to the +24V output bus at the earlier stage through the socket. The PIN PIN4 is a common ground wire end which is directly connected to a common ground wire, the enabling end PIN7 is connected to a corresponding I/O PIN of the single chip microcomputer through a connecting line of a mark M1-MEN (the specific connection rule is found in the distribution part of the PINs of the subsequent single chip microcomputer), and is grounded through a pull-down resistor R29 and an anti-interference capacitor C38; the PIN PIN3 at the output end of the switch tube has three paths connected to the outside: the main circuit is connected to the output end (labeled as M1-OUT +) of the module through an inductor L4, the second circuit is connected to a bootstrap power supply terminal PIN1 of an internal switching tube driving circuit through a capacitor C39 to provide a bootstrap signal for a driving tube, the third circuit is grounded through a freewheeling diode D16 to provide a freewheeling loop for an inductor L4 during the turn-off period of the internal switching tube; the PIN PIN8 is grounded through a timing capacitor C37 to determine the soft start time, and the compensation element access terminal PIN6 of the internal error amplifier is commonly grounded through a compensation capacitor C44 and a series combination circuit of C43 and R32 to stabilize the operation of the error amplifier; the output voltage feedback loop is obtained by a resistor divider, the upper arm of the resistor divider is a resistor R31, the lower arm of the resistor divider is formed by cascading two digital potentiometers U8 and U9, the voltage division point (the lower end of R31) of the resistor divider is connected to the input end of the output feedback voltage, sampling of the output voltage is achieved, and then the comparison result of the sampling value and the reference value is dynamically adjusted through an internal error amplifier to stabilize the output voltage of the module.

After the power input end (PIN PIN 2) of the module is powered by the front-stage +24V output bus through the socket, if the power input end is controlled by the single chip microcomputer, the TTL high level (+ about 5V) is added to the chip work enabling end (PIN PIN 7), and then the IC is started to enter a working state. After the on-time Ton, the internal power MOS is turned on, so that the input voltage is output through the PIN3 end and is applied to the left end of the inductor L4, the voltage is supplied to the external load of the module through the filter circuit formed by the inductor L4 and the capacitor C5, and magnetic field energy is stored in the inductor L4. After time Toff, the internal power MOS is turned off, and the reverse voltage generated across the energy storage inductor L4 is positive, negative, right, and left, so that the voltage applied across the freewheeling diode D16 is a forward bias voltage, which turns on the diode, and thus a discharge loop is formed between the inductor L4, the diode D16, and the external load, and the electric energy stored in the inductor L4 is discharged to the external load to provide the current required by the load.

2. Sampling circuit for output voltage and output current

the output voltage and output current of the module must be always under the monitoring of the singlechip, so that a corresponding acquisition and signal transmission loop must be arranged between the output and the AD input interface of the singlechip.

The output voltage acquisition part is a resistor voltage divider formed by connecting a resistor R35 and a resistor R30 in series, one end of a series body is connected to the output end of the module, the other end of the series body is grounded, a voltage dividing point is connected to the non-inverting input end of an operational amplifier U9B, the operational amplifier U9B is connected into a voltage follower mode to buffer signals, and the signals are transmitted to a voltage sampling AD input interface (label M1-I) of the single chip microcomputer after being clamped by a voltage stabilizing diode D17 and subjected to anti-interference filtering by a resistor R34 and a capacitor C40;

the output current acquisition component is a resistor R36 connected in series in the negative lead of the output loop, the voltage drop formed by the output current at the two ends of the resistor reflects the magnitude of the output current, but the voltage drop value is very small, and the voltage drop value is required to be amplified to be suitable for the analog quantity acquisition input requirement of the singlechip, so the two ends of the resistor R36 are respectively connected to the inverting and non-inverting input ends of the operational amplifier U9A through the resistors R27 and R28, and the current sampling signal is amplified by the U9A and then output from a pin1 to be sent to a current sampling AD input interface (the label M1-I) of the singlechip.

3. Digital potentiometer and interface connection line of digital potentiometer and single chip microcomputer

The digital potentiometers U8 and U9 are key elements giving programmable preset characteristics to the output voltage of the module, the digital potentiometers comprise configuration registers, data registers and nonvolatile memories, preset data can be read and written by a single chip microcomputer, and the digital potentiometers have the advantages of high adjustment precision, no noise, no mechanical wear, extremely long service life and the like. The digital potentiometer can conveniently realize programmable control, and can accurately measure and compensate and correct the control result through the singlechip and the AD conversion circuit.

In this embodiment, the digital potentiometers X9C103 and X9C102 are adopted, and the resistor networks of both potentiometers include 100 steps, and have the same pin distribution and input control characteristics, except that the total resistance of X9C103 is 10K, and the total resistance of X9C102 is 1K, which are different by one order of magnitude. The 8 th pin is a VCC power supply end, the 1 st pin (label INC) is an input end of a step control signal of a center head of the potentiometer, the 2 nd pin (label U/D) is an increment or decrement control end of the potentiometer, the 7 th pin (label CS) is a potentiometer chip selection enabling end, the 6 th pin (label VL) is an upper terminal of the resistor network of the potentiometer, the 4 th pin is a GND end and is also a lower terminal of the resistor network of the potentiometer, and the 5 th pin (label VW) is equivalent to a central tap of the resistor network of the potentiometer.

The 8 th pins of U8 and U9 are VCC power supply terminals and are connected to the 5V output terminal of the auxiliary power supply together; the 4 th pin is a GND terminal and is commonly connected to a common ground. The 7 th pin (chip select enable CS) of the first digital potentiometer U8 is connected to a pin of a single chip microcomputer (labeled M1-W1 EN), and the 7 th pin (chip select enable CS) of the second digital potentiometer U9 is connected to a pin of the single chip microcomputer (labeled M1-W2 EN); the 1 st pins (central head stepping control signals INC) of the two potentiometers are connected together and share the same connecting line to a pin of a singlechip (labeled M1-DIR); the 2 nd pins (increment or decrement control ends U/D) of the two potentiometers are also connected together and share the same connecting line to a pin of a single chip microcomputer (the label is M1-UD). Here, the reference numeral "M1" in parentheses denotes a first dc voltage level conversion module, and similarly, the reference numeral "M2-XX" corresponds to a second dc voltage level conversion module, and so on.

therefore, for each direct current voltage level conversion module, 2 analog sampling signal lines (output voltage and current) and 4 digital potentiometer control lines are connected with the single chip microcomputer, in addition, an enable end PIN7 of an MP1593 chip of a core component of a DC/DC part also needs to be connected to the single chip microcomputer for connection and disconnection control of output, in sum, each module occupies 7I/O interfaces (including 2 analog quantity sampling input interfaces and 5 digital control interfaces) of the single chip microcomputer, and therefore the four modules occupy 28I/O interfaces (including 8 analog quantity sampling input interfaces and 20 digital control interfaces) of the single chip microcomputer in total.

Specifically, the following are: the embodiment designs a unique connection application mode of cascading two digital potentiometers with different numerical values, and greatly improves the preset voltage precision of the module. The principle is as follows:

As can be seen from fig. 5, the digital potentiometer is connected to the circuit as part of the output resistor divider, which is the lower half of the resistor divider, and together with the upper half of the resistor divider (fixed resistor R31) determines the voltage dividing ratio of the divider, and thus the magnitude of the module output voltage. Therefore, under the condition that the total resistance value is the same, the more the stepping gears of the digital potentiometer are, the thinner the resistance value change between each adjacent gear is, and the more accurate the preset voltage can be. However, excessive stepping gears are impractical, costly and difficult to manufacture, and excessive stepping gears slow down the speed of gear selection and positioning, making it difficult to achieve both.

If we use one of the digital potentiometers with a larger resistance value for each step and another digital potentiometer with a smaller resistance value for each step and cascade them together, we can form a combination form for "coarse adjustment" and another combination form for "fine adjustment", for example, each potentiometer has 100 steps, and the resistance of each step of the "coarse adjustment" potentiometer is 10 times that of each step of the "fine adjustment" potentiometer, and this combination obviously forms a digital potentiometer with 100 × 100=10000 steps (because some combinations have equivalence relations, the actual effective resistance value is less than that), and the minimum selectable value of the resistance between the steps still maintains the resistance level between the steps of the "fine adjustment" potentiometer. Obviously, the coarse adjustment can quickly approach the required resistance value, the gear selection speed is accelerated, and the fine adjustment ensures the gear selection accuracy. At present, the digital potentiometer is a mature product and is low in price, and the available precision is improved by more than one order of magnitude by only increasing very low cost in the combination mode, so that the digital potentiometer is an expansion method with very high practical value.

A core control module of the single chip microcomputer, as shown in fig. 4:

The part takes a single chip microcomputer as a core to realize intelligent regulation of output voltage and current limiting threshold of a multi-path direct current voltage grade conversion module, on one hand, the single chip microcomputer is provided with a field debugging interface to conveniently realize adjustment and configuration of each path of output voltage on the field, on the other hand, the single chip microcomputer is also provided with an industrial control bus type communication interface to exchange data with an operation and maintenance center through a communication network and set output voltage parameters and the highest output current of each path in a remote control mode.

In this embodiment, an STM32F103C8 single chip microcomputer is adopted, the operating power VCC is 3.3V, and there are 35 available I/O pins, including PA0 to PA15, PB0 to PB15, and PC13 to PC15, in addition to the reset pin RST, the crystal oscillator pins XO and XI, the standby power access pin VBAT, and the BOOT0 pin. The specific allocation is as follows:

5. Pin assigned to "RS 485 communication interface":

PA2 (USART-TX), serial data transmitting end;

PA3 (USART-RX), serial data receiving end.

6. pins assigned to the "field debug interface":

PA13 (SWDIO) debug data port line;

PA 14: (SWCLK) debug clock port lines;

7. and each direct current voltage grade conversion module (hereinafter referred to as an output module) is distributed to carry out output voltage and current sampling (an analog input port of AD conversion is required):

PA4, PA 5: respectively used for sampling the voltage and the current of the module 1;

PA6, PA 7: respectively for voltage and current sampling of the module 2;

PA8, PA 9: respectively for voltage and current sampling of the module 3;

PA10, PA 11: for voltage and current sampling of the module 4, respectively;

8. Each output module is distributed to carry out digital potentiometer control:

PA12, PB 0-PB 3: the control circuit is sequentially and respectively used for enabling a DC/DC chip, a potentiometer 1, a potentiometer stepping, the moving direction of a potentiometer center head and a potentiometer 2 in an output module 1;

PB 4-PB 8: the control method is sequentially and respectively used for enabling a DC/DC chip, a potentiometer 1, a potentiometer stepping, the moving direction of a potentiometer center head and a potentiometer 2 in a module 2;

PB 9-PB 13: the control circuit is sequentially and respectively used for enabling a DC/DC chip, a potentiometer 1, a potentiometer stepping, the moving direction of a potentiometer center head and a potentiometer 2 in a module 3;

PB 14-PB 15, PC 13-PC 15: the control method is sequentially and respectively used for enabling a DC/DC chip, a potentiometer 1, a potentiometer stepping, the moving direction of a potentiometer center head and a potentiometer 2 in a module 4;

therefore, the pins of the single chip microcomputer are completely distributed except the PA15, and the resources in the chip microcomputer are fully utilized.

In practical use, the output voltage needs to be measured once every operation step, and if the first gear is executed sequentially, the method is very tedious, time-consuming and extremely low in efficiency. In order to improve the efficiency and accelerate the adjustment speed, the adjustment can be carried out in a small range near the required voltage by adopting a quick table look-up mode in one step, and then fine adjustment is carried out. The specific method belongs to the field of software technology and is not discussed in depth here.

A communication interface module, as shown in fig. 6:

The communication interface module is matched with a special serial port communication pin in the single chip microcomputer to form an interface with an external transmission network, and the communication interface module is used for exchanging data with an operation monitoring center and obtaining the support of the center so as to realize remote control presetting and intelligent supervision of the power supply. The intelligent integrated power supply device is a significant component which is not negligible because the intelligent integrated power supply device is endowed with special performance of remote centralized scheduling configuration and monitoring.

The communication interface module is mainly an ADI ADM2483 chip, the chip is a newly-developed isolation type RS485 transceiver, the ICOUpler (magnetic coupling) isolation technology of the ADI patent is integrated inside, functionally, the communication interface module is equivalent to the integration of three single-channel optical couplers and an RS485 transceiver, the speed is 500Kbps, and the communication interface module has the following advantages:

1. The volume is small: the interface of the traditional RS485 communication needs to adopt a DC-DC isolation power supply module besides power supply, and also needs to use an MAX485 chip and three optocouplers, only one ADM2483 chip is adopted in the new technology, and the magnetic isolation technology belongs to a voltage type and does not need to be externally connected with a current-limiting resistor. Because the signal isolation is integrated in the device, the receiving pin, the sending pin and the control pin can be directly connected with the CPU. Greatly simplifying the circuit and improving the performance of the module.

2. The power supply monitoring device has the unique power supply monitoring function: the front end of the ADM2483 supports 3.3V/5V power supply, and is provided with a power supply monitoring pin PV, the function of the pin is to monitor the power supply of the ADM2483, when the power supply is lower than 2.0V, the ADM2483 does not work, and the pin outputs low level; when the power supply is higher than 2.0V, ADM2483 enters a working state, the pin is automatically set high, and the pin can provide a single chip microcomputer as one of monitoring signals of a communication port.

3. and the ADM2483 internally integrated RS485 transceiver has the functions of thermal cut-off and input failure protection.

The actual circuit diagram of the communication interface module is illustrated as follows:

The No. 2 and No. 8 pins are ground wire pins of the non-isolated side and are directly connected with a ground wire end (GND) of the single chip microcomputer, and the No. 1 pin is a working power supply end of the non-isolated side and is connected to a +3.3V power supply output point of a power supply part of the single chip microcomputer in the front public power supply.

A3 rd pin (RXD) of a communication interface chip U6 (ADM 2483) is a serial receiving end and is connected to a PA3 pin of the singlechip U4; a6 th pin (TXD) of the U6 is a serial sending end and is connected to a PA2 pin of the singlechip, and the two lines form a main loop of communication;

U6 pin4 (RE \ is the receive enable, active low; the No. 5 pin (DE) of U6 is a sending enable end, the high level is effective, the two are combined together and connected to the PA0 pin of the single chip U4, thus, when the PA0 pin is controlled to be the low level, the communication interface chip is in a receiving state; and when the pin of the PA0 is controlled to be in a high level, the communication interface chip is in a sending state, and the control on the receiving and sending directions is realized.

The isolated power supply chip U5 provides an isolated power supply for the communication interface chip U6 (ADM 2483), and the 1 st pin of the isolated power supply chip U5 is a non-isolated power supply input positive terminal and is taken from a +5V power supply output point output by the 'single chip microcomputer power supply part'. The non-isolated input negative terminal (pin 2) is grounded, the pin4 is an isolated output positive terminal, the pin 16 connected to the isolated side of the communication chip U6 supplies power to the communication chip U6, and the output negative terminal (pin 3) is an isolated communication interface outer side reference ground terminal. Therefore, on the premise of ensuring the integrity of transmission signals, the internal and external circuits of the communication interface chip are electrically and completely isolated, and the working stability and the operation safety of the internal circuits such as the singlechip and the like are ensured.

Outside the communication interface chip U6, the 12 th pin (B) and the 13 th pin (a) constitute a differential half-duplex communication interface loop, except for the isolated power input port. Because the external line is connected and a certain anti-noise threshold is introduced, a group of resistance voltage division networks and a group of clamping networks are arranged. The resistor voltage-dividing network is formed by connecting resistors R22, R26 and R23 in series, the lower end of R23 is connected with the output anode (485V) of the isolation power supply chip, the upper end of R22 is connected with the output cathode of the isolation power supply chip, and the two ends of the middle resistor R26 of the series body are respectively connected with the pin (B) and the pin (A) of the chip U5, so that the voltage of the pin (A) is higher than that of the pin (B), a bias threshold between the pins (A) and (B) is formed, and the anti-interference capability is improved. The group of clamping networks is composed of clamping diodes D13, D14 and D15, the D14 is arranged between pins (A) and (B), and the D15 and the D13 are respectively arranged between the pins (A) and (B) in an outside isolated mode and are used for absorbing large induction voltage possibly appearing on a line and protecting the safety of an interface.

The 7 th pin (PV, power supply monitoring signal) of the communication interface chip U6 is directly connected to the PA1 pin of the single chip, so that the single chip can know the working condition of the power supply of the communication interface chip at any time.

As mentioned above, the intelligent integrated power supply device is mounted in the cylindrical inner space of the lamp pole by taking a public lighting lamp pole as a support, shares the same commercial power supply resource with the lighting lamp, and provides a power adapter of a corresponding direct current working power supply for various different internet of things front-end devices or equipment, so that the intelligent integrated power supply device has clear structural characteristics and performance characteristics, and is specifically embodied in the following aspects:

secondly, the current transformation circuit in the intelligent integrated power supply device adopts a two-stage working mode,

The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.

Claims

1. The utility model provides a thing networking intelligent integrated power supply device which characterized in that: the system comprises a preposed public power supply module, a singlechip core control module, a direct-current voltage grade conversion module and a communication interface module;

The prepositive public power supply module comprises an AC/DC prepositive basic voltage stabilizing circuit and an auxiliary power supply circuit;

Wherein, the leading basic voltage stabilizing circuit of AC/DC includes: the input power supply is connected to the input of the incoming line filter circuit, the output of the incoming line filter circuit is connected to the input of the full-wave rectification circuit, the output of the full-wave rectification circuit is connected to the input of the single-stage PFC flyback switch inverter circuit, the single-stage PFC flyback switch inverter circuit is connected to a primary winding of the high-frequency isolation transformer, and a secondary winding of the high-frequency transformer is connected to the secondary rectification filter circuit; the power supply is used for finishing the functions of power supply anti-interference, power factor compensation, AC-DC isolation conversion and DC voltage stabilization output; after the AC/DC prepositive basic voltage stabilizing circuit rectifies 220V alternating current commercial power, the integrated chip of the single-stage PFC flyback switch inverter circuit drives the single-stage PFC flyback switch inverter circuit and the high-frequency isolation transformer to carry out inversion, isolation and voltage reduction treatment, and then the alternating current is converted into +24V direct current output through secondary rectification and filtering, and the direct current output is transmitted to a direct current power supply bus of a multi-output stage to provide input direct current power supply for each multi-output stage module of the rear stage; meanwhile, the auxiliary power supply circuit is provided with required direct current power supply so as to maintain the normal work of the core control module of the single chip microcomputer;

the auxiliary power supply circuit adopts a DC-DC switch conversion mode to further convert the +24V power supply stably output by the AC/DC preposed basic voltage stabilizing circuit into a stable +3.3V and +5V power supply for a singlechip core control module and a communication interface module; the power supply input end of the auxiliary power supply circuit is connected to a +24V direct-current output bus of the AC/DC preposed basic voltage stabilizing circuit, a +5V output voltage is obtained after the voltage stabilizing circuit passes through the non-isolated switch, the +5V output is divided into two paths, and one path of the output becomes a +3.3V power supply after precise linear voltage stabilization and is used for supplying power to the core control module of the single chip microcomputer; the other path still maintains +5V voltage after isolated DC/DC conversion and supplies power to the RS485 communication interface module;

The single chip microcomputer core control module adopts a universal single chip microcomputer with multiple I/O interfaces and is used for realizing intelligent regulation of output voltage and current limiting threshold of the multi-path direct current voltage grade conversion module; the single chip microcomputer is provided with a field debugging interface for realizing the adjustment and configuration of each output voltage on the field; the single chip is also provided with an industrial control bus type communication interface, exchanges data with an operation and maintenance center through a communication network, and sets output voltage parameters and the highest output current of each path in a remote control mode;

the direct-current voltage grade conversion module comprises four identical modules, each module comprises a DC/DC converter circuit, a current/voltage sampling circuit and digital potentiometers U8 and U9, the current/voltage sampling circuit is connected to the output end of the DC/DC converter circuit, and the digital potentiometers U8 and U9 are connected to the output end and the feedback input end of the DC/DC converter circuit; for performing: converting a +24V direct-current power supply sent by a front public power supply module into output direct-current power supplies with different voltage levels; receiving an adjusting instruction sent by the singlechip through a group of control buses, and realizing the adjustment control of the output direct-current voltage of the module through the operation of the digital potentiometer; the voltage stabilizing function of the output voltage of the module is realized through a voltage closed loop feedback circuit in a DC/DC converter circuit; the current/voltage sampling circuit is under the monitoring of the singlechip, and a current/voltage sampling signal acquired by the current/voltage sampling circuit is sent to a voltage sampling AD input interface of the singlechip; a protection control signal is sent back to the singlechip through a current/voltage sampling circuit, so that the fault protection of the module is realized;

In the direct-current voltage class conversion module, a DC/DC converter circuit adopts an MP1593 chip, a PIN PIN2 of the MP1593 chip is a power supply input end, a PIN PIN4 is a public ground terminal, a PIN PIN7 is a chip work enabling end, a PIN PIN3 is an output end of an internal power switch tube, a PIN PIN1 is a bootstrap power supply end of an internal switch tube driving circuit, a PIN PIN8 is a soft start time setting end, a PIN PIN5 is a feedback input end, and a PIN PIN6 is a compensation element access end of an internal error amplifier;

the power input end is directly connected to a +24V direct-current output bus of the AC/DC prepositive basic voltage stabilizing circuit through a socket; the common ground wire end is directly connected to the common ground wire, the PIN7 of the enable end is connected to the corresponding I/O PIN of the singlechip through a wire, and is grounded through a pull-down resistor R29 and an anti-interference capacitor C38 which are connected in parallel; the PIN PIN3 at the output end of the switch tube has three paths connected to the outside: the main circuit is connected to the output end of the direct-current voltage grade conversion module through an inductor L4, the second circuit is connected to a bootstrap power supply end PIN PIN1 of the internal switching tube driving circuit through a capacitor C39 to provide a bootstrap signal for the driving tube, the third circuit is grounded through a freewheeling diode D16 to provide a freewheeling circuit for the inductor L4 during the turn-off period of the internal switching tube; the PIN8 is grounded through a timing capacitor C37, and the PIN6 of the compensating element of the internal error amplifier is grounded through a compensating capacitor C44 and a series combination circuit of C43 and R32 in common, so that the operation of the error amplifier is stabilized; the voltage closed-loop feedback circuit is obtained by a resistor divider, the upper arm of the resistor divider is a resistor R31, the lower arm of the resistor divider is formed by cascading two digital potentiometers U8 and U9, the upper end of the resistor R31 is connected to the output end of the DC/DC converter circuit, the voltage division point of the resistor divider, namely the lower end of the resistor R31, is connected to a PIN PIN5, sampling of the output voltage is achieved, and then the comparison result of the sampling value and the reference value is dynamically adjusted through an internal error amplifier to stabilize the output voltage of the module;

2. The intelligent integrated power supply device of the internet of things according to claim 1, wherein: the AC/DC prepositive basic voltage stabilizing circuit adopts an AC-DC working mode, outputs in a single path, and has the capacity of 24V/2A and 50W; FT822 is selected as the integrated chip U1.

3. The intelligent integrated power supply device of the internet of things according to claim 2, wherein: the AC/DC pre-basic voltage stabilizing circuit comprises: alternating current commercial power is sent into a surge absorption and anti-interference filter circuit comprising a voltage dependent resistor RV1, a capacitor C1, a common mode inductor L1, a capacitor C2, a capacitor C3 and a capacitor C4 through an interface JP1 and a fuse F1, and then is rectified into pulsating direct current through a full-wave rectification circuit and then is sent to a power switch circuit for chopping processing;

The integrated chip U1 is a drive control component of a power switch tube, and the +250V voltage of the output end of the rectifier bridge is connected to the 8 th pin, namely the working power supply input of the U1, through resistors R4 and R5 to be used as an initial drive power supply at the starting moment; the 3 rd pin of the integrated chip U1 is connected to the voltage division point of a voltage divider formed by resistors R1, R2 and R3; the 5 th pin of the integrated chip U1 is connected to the connection point of the secondary coil of the transformer and the secondary rectifier tube D5; the 4 th pin of the integrated chip U1 is connected to the upper end of a Q1 source current sampling resistor R10;

a voltage divider comprising resistors R17 and R18 is arranged at the output end of +24V, after a sampled value is compared with a reference value inside a chip Q2 and is subjected to difference amplification by a high-gain amplifier inside a Q2, a difference signal passes through a light emitting diode of an optical coupler OPT1 in the form of current change, so that a corresponding isolated difference signal is obtained on a secondary series resistor R14 of the optical coupler OPT1, then the signal is sent to a pin1 of an integrated chip U1 through a resistor R7 to change the operation parameter of the U1, a corresponding driving pulse is output through a pin7, and the driving pulse is sent to a grid electrode of a VMOS high-power switch tube Q1 through the resistor R8 to realize closed-loop voltage stabilization control of the output voltage of + 24V.

4. The intelligent integrated power supply device of the internet of things according to claim 1, wherein: the single chip microcomputer adopts an STM32F103C8 single chip microcomputer, a working power supply VCC is 3.3V, and 35 available I/O pins, namely PA 0-PA 15, PB 0-PB 15 and PC 13-PC 15, are arranged besides a reset pin RST, crystal oscillator pins XO and XI, a standby power supply access pin VBAT and a BOOT0 pin.

5. The intelligent integrated power supply device of the internet of things according to claim 1, wherein: the communication interface module adopts an ADM2483 chip and is an isolated RS485 transceiver.