CN213817229U

CN213817229U - Microcomputer protection device with metering function

Info

Publication number: CN213817229U
Application number: CN202022848829.0U
Authority: CN
Inventors: 陈功
Original assignee: Sichuan Ziqi Electric Appliance Co ltd
Current assignee: Sichuan Ziqi Electric Appliance Co ltd
Priority date: 2020-12-02
Filing date: 2020-12-02
Publication date: 2021-07-27
Anticipated expiration: 2030-12-02

Abstract

The utility model relates to a microcomputer protection device with metering function, a processor, an analog quantity acquisition module, a keyboard display module, a watchdog circuit, a communication module, an outlet module and a power module for providing electric power support for the device, wherein the analog quantity acquisition module, the keyboard display module, the watchdog circuit, the communication module and the outlet module are connected with the processor; the output end of the analog quantity acquisition module is also connected with an AD conversion module, the AD conversion module is sequentially connected with an encoder, the encoder is connected with a trigger, and the trigger is connected with the processor and the outlet module; the scheme adopts the mode of the external AD conversion module to realize the synchronous receiving of the analog signals and the digital signals of the processor, wherein the digital signals are only used for realizing counting, the accurate transmission of data is realized by depending on the analog quantity, the metering is finished, the data precision is ensured, the cost is lower, and the requirement on the AD conversion module is lower.

Description

Microcomputer protection device with metering function

Technical Field

The utility model relates to a computer protection field, concretely relates to take computer protection device of measurement function.

Background

The microcomputer protection is relay protection formed by microcomputer, and has high reliability, high selectivity and high sensitivity. The system is widely applied to electric power, petrifaction, mine smelting, railways, civil buildings and the like. The digital core of the microcomputer protection device generally consists of a CPU, a memory, a timer/counter, a Watchdog and the like. At present, the mainstream of the digital core is an embedded Microcontroller (MCU), which is known as a single chip microcomputer, and the input/output channels include an analog input channel (analog input conversion loop (converting the quantities measured by CT and PT into lower voltage quantities suitable for internal a/D conversion, 2.5V, +/-5V or +/-10V), a low-pass filter and sampling, and a/D conversion) and a digital input/output channel (man-machine interface and various alarm signals, trip signals, and electrical pulses, etc.).

The defects of the prior art are as follows: the metering function of the traditional microcomputer system is generally realized by a multi-bit digital circuit formed by A/D conversion in a sampling circuit, so that the finally received data of a processor is a digital signal, for example, the current sampling value range is 0-10 mA, 10-bit AD can be adopted to reach one bit after a decimal point, the requirement of protecting most motors can be approximately met, and in order to fully utilize chip resources as much as possible, on-chip AD conversion is adopted for design. However, considering the strictness of the protection and especially the monitoring accuracy requirements, the chip is generally expanded to better meet the accuracy requirements, which has the disadvantage of increasing the cost.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome prior art not enough, provide a take microcomputer protection device of measurement function, the mode that adopts external AD conversion module realizes the analog signal of treater, digital signal's synchronous receipt, and wherein digital signal only is used for realizing the count, relies on analog quantity self to realize the accurate transmission of data, has both accomplished the measurement and has guaranteed the data precision, and the cost is lower simultaneously, and is lower to AD conversion module's requirement.

The purpose of the utility model is realized through the following technical scheme:

a microcomputer protection device with a metering function comprises:

the device comprises a processor, an analog quantity acquisition module, a keyboard display module, a watchdog circuit, a communication module, an outlet module and a power supply module, wherein the analog quantity acquisition module, the keyboard display module, the watchdog circuit, the communication module, the outlet module and the power supply module are connected with the processor;

the output end of the analog quantity acquisition module is also connected with an AD conversion module, the AD conversion module is sequentially connected with an encoder, the encoder is connected with a trigger, and the trigger is connected with the processor and the outlet module;

the AD conversion module outputs 1 to the analog quantity number which is larger than or equal to the threshold K, the analog quantity number which is smaller than the threshold K is output to 0, the encoder is used for counting the accumulated output value of the AD conversion module, and when the accumulated output value is larger than the threshold F, the trigger is activated to send corresponding control words to the processor and the exit module.

Further, the precision of the AD conversion module is 2 bits.

Further, the processor is composed of a TMS320F240 micro-processing system.

Further, the outlet module is provided with an expansion interface.

Furthermore, the communication module is composed of a CAN communication module circuit, Philips SJA1000 is used as a CAN controller, and a driver adopts a CAN controller interface chip PCA82C 250.

Furthermore, the trigger is formed by a D trigger.

Further, the threshold K is a parameter upper limit value of the device in a normal operation state.

The utility model has the advantages that: according to the scheme, the low-order AD conversion module is utilized to complete the measurement of the fault state, the running state of the equipment is monitored by the processor through direct uploading of the analog quantity, namely, the running state is used as the input of the protection function of the watchdog circuit, the normal running of the system is ensured, the cost is reduced, the precision requirement on the AD module is greatly reduced, the fault quantity can be recorded, when the fault quantity reaches the upper limit value, the system is shut down for maintenance or replacement, and equivalently, an equipment running abnormal log is formed.

Drawings

Fig. 1 is a schematic block diagram of the present invention.

Detailed Description

The technical solution of the present invention is described in further detail below with reference to the accompanying drawings, but the scope of the present invention is not limited to the following description.

As shown in fig. 1, a microcomputer protection device with a metering function includes:

the AD conversion module outputs 1 to the analog quantity number which is larger than or equal to the threshold K, the analog quantity number which is smaller than the threshold K is output as 0, the encoder is used for counting the accumulated output value of the AD conversion module, and when the accumulated output value is larger than the threshold F, the trigger is activated to send corresponding control words to the processor and the exit module.

Optionally, in the microcomputer protection device with the metering function, the precision of the AD conversion module is 2 bits, that is, the display of 00 binary bits is realized, so that the signal output of 0 and 1 can be completely satisfied.

Optionally, the processor of the microcomputer protection device with the metering function is formed by a TMS320F240 micro-processing system. TMS320F240 is a dedicated fixed point programmable chip which is introduced by TI company in 1997 on the basis of TMS320C2xx, integrates a DSP core and various peripheral devices on a single chip, and can solve various engineering application schemes. In order to simplify the system design, some peripheral control circuits of the system can be realized by cpld (complex programmable logic device). CPLD from XILINX was chosen for the design, where XC9500 series products used in-system 5V programmable FASTFLASH technology and contained internal JTAG bi-directional scan test logic. In this embodiment, a circuit schematic diagram manner is adopted to perform logic editing on the CPLD.

Optionally, in the microcomputer protection device with the metering function, the outlet module is provided with an expansion interface. The output module, namely the switching value input/output circuit, mainly completes the input of the state signal and the output of the action signal. Since the number of expansion ports of the CPU of the relay protection device is generally small and cannot satisfy the input/output requirements, it is often necessary to expand the ports when reading the input amount and the output amount. The partial function of the device is integrated in the CPLD and hung on the internal address/data bus.

Optionally, in the microcomputer protection device with the metering function, the keyboard display module adopts a membrane keyboard, 9 keys are provided in total, and the setting value, the actual time modification, the on-site operation of the switch and the like can be set visually on line and off line only by combining the menu with the six keys through the upper key, the lower key, the left key, the right key, the cancel key and the confirmation key. And adopting an interrupt mode corresponding to the keyboard to reduce the occupation of the CPU.

Optionally, in the microcomputer protection device with the metering function, the communication module is formed by a CAN communication module circuit, Philips SJA1000 is used as a CAN controller, and the driver uses a CAN controller interface chip PCA82C 250. PCA82C50 is an interface of the CAN protocol controller and the physical bus, provides different transmission capabilities for the bus and different reception capabilities for the CAN controller, is fully compatible with the ISO11898 standard, and has short circuit protection functions for the battery and ground.

Optionally, the trigger of the microcomputer protection device with the metering function is formed by a D trigger.

In addition, the present embodiment also provides a software design scheme for the microcomputer protection device.

In the software design of the microcomputer protection device, an alternating current sampling algorithm and a protection algorithm are mainly considered, and whether protection acts or not is judged according to a certain protection algorithm through data obtained by sampling. The traditional one-point, two-point, three-point and root-mean-square sampling algorithms are considered based on the situation that voltage and current are pure sinusoidal changes, and when an actual motor fails, attenuated non-periodic components and various high-frequency components are often superposed on the basis of fundamental waves, so that a microcomputer protection device is required to preprocess input current and voltage signals and filter out the non-periodic and high-frequency components as far as possible. Considering the strong function of filtering higher harmonics of the Fuji algorithm, but the full-wave Fuji algorithm needs N sampling data of a cycle, the response speed is slow, and in order to improve the protection rapidity, on the basis of comparing various existing improved half-wave Fuji algorithms, a rapid algorithm combining the half-wave Fourier algorithm and the Mann-Morrison algorithm is determined, the real part of the fundamental wave is calculated by the half-wave Fuji algorithm, and the amplitude of the fundamental wave is calculated by the Mann-Morrison algorithm, so that the advantage of the response speed of the half-wave Fuji algorithm can be kept, and the defect of weak filtering function can be overcome.

The software of the motor protection device adopts the modularized design idea and consists of a main program module, an interrupt service subprogram module and all function subprogram modules. The actual programming adopts C language and assembly mixed writing, improves the data processing capability and also ensures the reliability of the program.

The foregoing is illustrative of the preferred embodiments of the present invention, and it is to be understood that the invention is not limited to the precise forms disclosed herein, and that various other combinations, modifications, and environments may be resorted to, falling within the scope of the invention as defined by the appended claims. But that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention, which is to be limited only by the claims appended hereto.

Claims

1. A microcomputer protection device with a metering function is characterized by comprising:

2. The microcomputer protection device with the metering function as claimed in claim 1, wherein the precision of the AD conversion module is 2 bits.

3. The microcomputer protection device with metering function of claim 2, wherein the processor is composed of a TMS320F240 micro-processing system.

4. The microcomputer protection device with the metering function as claimed in claim 3, wherein the outlet module is provided with an expansion interface.

5. The microcomputer protection device with the metering function as claimed in claim 4, wherein the communication module is formed by a CAN communication module circuit, Philips SJA1000 is used as a CAN controller, and a driver adopts a CAN controller interface chip PCA82C 250.

6. The microcomputer protection device with the metering function as claimed in claim 5, wherein the trigger is a D trigger.

7. The microcomputer protection device with the metering function as claimed in claim 6, wherein the threshold value K is a parameter upper limit value under a normal operation state of the equipment.