CN206132838U - Wireless current detection device - Google Patents

Abstract

The utility model relates to measurement technology, in particular to a wireless current detection device, which is characterized in that it includes an alternating current output and a host computer, and also includes a current-type transformer system, a filter system, an auxiliary power supply system, a single-chip microcomputer processing and Bluetooth transmission system; the current transformer system and the filter system are connected in series to the alternating current output, the output of the filter system is used as the input of the single-chip microcomputer processing and the bluetooth transmission system, the output of the single-chip microcomputer processing and the bluetooth transmission system is used as the system output, and the auxiliary power system is respectively Connect the current transformer system, filter system, single-chip processing and Bluetooth transmission system; the output of the single-chip processing and Bluetooth transmission system is connected to the host computer. The device can sample alternating current with harmonics with high precision, the system has low power consumption, stable and accurate output, and can be manually calibrated and displayed in real time through the host computer.

Description

A wireless current detection device

technical field

The utility model belongs to the technical field of measurement, in particular to a wireless current detection device.

Background technique

Wireless current detection technology is a technology that converts the alternating current on the transmission line into a voltage through a mutual inductance transformer, and then collects it. The main uses of wireless current detection devices are: 1. Industrial applications: current measurement on power grid transmission lines, generator output current monitoring, motor input current monitoring, and measurement of current in power systems such as three-phase alternating power supplies. 2. Enterprise application: evaluate the output characteristics of the produced constant current and constant voltage source, including the harmonic spurious degree of its output, etc. 3. Civilian use: state detection of household and vehicle portable power supplies, etc. In modern production, due to the increase of electrical appliances and the complex impedance characteristics of the grid voltage, the current fed back to the grid will contain a lot of harmonic components. Normal, and for strong current network or weak current network, the current detection device connected by wire has a certain interference to the main circuit. Therefore, it is necessary to design an isolated current sensing device with a harmonic measurement function to meet the detection requirements of different occasions.

From a principle point of view, current transformers are widely used to detect alternating currents. The methods for measuring harmonics include filtering methods based on analog circuits and Fourier transform methods based on digital processing systems. Among them, the Fourier transform method can perform Fourier transform on the sampled AC signal through the digital system, and then perform filtering in the digital domain. The system is relatively simple, but the real-time performance is not good, and the delay of different processing systems is different. The filtering method based on the analog circuit is to directly separate the signal through the analog filter, and the function of the digital system is only sampling and display, and the real-time performance of the system is better and the stability is higher. In some current applications, the current detection device mostly separates frequencies through filters of different frequency bands, which makes the filter system more complicated.

Utility model content

The purpose of the utility model is to propose a medium and small alternating current detection device with high sampling precision, good real-time performance, simple system and good human-computer interaction.

In order to achieve the above purpose, the technical solution adopted by the utility model is: a wireless current detection device, including an alternating current output and a host computer, and also includes a current-type transformer system, a filter system, an auxiliary power supply system, a single-chip microcomputer processing and a Bluetooth Sending system; current-type transformer system and filter system are connected in series to the alternating current output, the filter system is connected to the input end of the single-chip processing and Bluetooth sending system, the output end of the single-chip processing and Bluetooth sending system is connected to the host computer, and auxiliary power supply The system is respectively connected with the current transformer system, the filter system, the single-chip microcomputer processing and the bluetooth transmission system.

In the above wireless current detection device, the current transformer system includes a transformer and an amplifier circuit; the input end of the transformer is connected to the alternating current output, and the amplifier circuit is connected to the output end of the transformer.

In the above-mentioned wireless current detection device, the turns ratio of the primary and secondary coils of the transformer is 1:14, the magnetic core is ZS157125 sendust, and the core operational amplifier of the amplifier circuit adopts the OPA313 single-supply operational amplifier.

In the above wireless current detection device, the filter system includes a third-order active low-pass filter and a third-order active high-pass filter; the third-order active low-pass filter and the third-order active high-pass filter are connected in parallel amplifier circuit output.

In the above wireless current detection device, the core operational amplifiers of the third-order active low-pass filter and the third-order active high-pass filter are both OPA313 single-supply operational amplifiers; the cut-off frequency of the third-order active low-pass filter is 1300Hz , the cutoff frequency of the third-order active high-pass filter is 2700Hz.

In the above wireless current detection device, the auxiliary power supply system includes a large capacitor charging circuit, a BOOST boost circuit based on TPS61073; the large capacitor charging circuit includes a 10 ohm current limiting resistor, a low conduction voltage drop diode B10100 and a 2.2F capacitor, A 2.2F capacitor is connected in parallel with a 10uf capacitor to reduce the output ripple. After the TPS61073-based BOOST boost circuit is connected in series with a large capacitor charging circuit, the input of the TPS61073-based BOOST boost circuit is limited to more than 1.8V, and the output voltage is constant. 5V.

In the above-mentioned wireless current detection device, the single-chip processing and bluetooth transmission system includes a single-chip system and a bluetooth data transmission system, the single-chip system is connected to the output port of the filter system, the sending end of the bluetooth data transmission system is connected to the IO port of the single-chip system, and the bluetooth data transmission system receives The terminal is connected to the USB port of the host computer; the auxiliary power supply system provides 5V voltage for the microcontroller system.

In the wireless current detection device mentioned above, MSP430F5529 is used in the single-chip microcomputer system, and TICC2650 is used in the bluetooth data transmission system.

The working principle of the utility model: with the current transformer system and the filter system as the core, the alternating current sampling and the separation of the fundamental wave of 1000Hz, the second harmonic of 2000Hz and the third harmonic of 3000Hz are completed. Use MSP430F5529 to sample the AC voltage after filtering and amplifying, and send the amplitude of the fundamental wave, the amplitude of the second harmonic and the amplitude of the third harmonic to the host computer through the Bluetooth system. The system uses a 2.2F capacitor as a system energy storage component to provide power for offline work, and a 5V constant output voltage is provided by the TPS61073 boost chip to power the system. Wirelessly measure the alternating current of 10mA to 1.5A effective value, and measure the fundamental wave contained in the alternating current, the second and third harmonic amplitude values, and display them in real time through the host computer.

The beneficial effect of the utility model is that the sampling of the alternating current containing harmonics can be performed with high precision, the power consumption of the system is low, the output is stable and accurate, and manual calibration can be performed.

Description of drawings

Fig. 1 is a structural representation of an embodiment of the utility model;

Fig. 2 is a circuit diagram of a current transformer system of an embodiment of the present invention;

Fig. 3(a) and Fig. 3(b) are circuit diagrams of the filter system of an embodiment of the present utility model;

Fig. 4 is a structural circuit diagram of an auxiliary power supply system according to an embodiment of the present invention;

Fig. 5 is a circuit diagram of a single-chip microcomputer processing and bluetooth transmission system of an embodiment of the present invention.

detailed description

Embodiments of the present utility model will be described in detail below in conjunction with the accompanying drawings.

Examples of the described embodiments are shown in the drawings, wherein like or similar reference numerals designate like or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, and are only used to explain the present invention, and cannot be construed as limiting the present invention.

The following disclosure provides many different embodiments or examples for realizing different structures of the present invention. To simplify the disclosure of the present invention, components and arrangements of specific examples are described below. They are examples only and are not intended to limit the invention. Furthermore, the present invention may repeat reference numerals and/or letters in different instances. This repetition is for the purpose of simplicity and clarity and does not in itself indicate a relationship between the various embodiments and/or arrangements discussed. Additionally, the present disclosure provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize the applicability of other processes and/or the use of other materials. Additionally, configurations described below in which a first feature is "on" a second feature may include embodiments where the first and second features are formed in direct contact, and may include additional features formed between the first and second features. For example, such that the first and second features may not be in direct contact.

In the description of the present utility model, it should be noted that, unless otherwise stipulated and limited, the terms "connected" and "connected" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection, or it can be the internal communication of two elements , may be directly connected, or may be indirectly connected through an intermediary. Those of ordinary skill in the art can understand the specific meanings of the above terms according to specific situations.

The technical solution adopted in this embodiment is as follows: a wireless current detection device, including an alternating current output and a host computer, and also includes a current-type transformer system, a filter system, an auxiliary power supply system, a single-chip microcomputer processing and a Bluetooth transmission system; The transformer system and filter system are connected in series to the alternating current output, the filter system is connected to the input end of the single-chip processing and Bluetooth transmission system, the output end of the single-chip processing and Bluetooth transmission system is connected to the upper computer, and the auxiliary power system is respectively connected to the current type Transformer system, filter system, single-chip processing and bluetooth transmission system.

Further, the current transformer system includes a transformer and an amplifier circuit; the input end of the transformer is connected to the output of the alternating current, and the amplifier circuit is connected to the output end of the transformer.

Furthermore, the turns ratio of the primary and secondary coils of the transformer is 1:14, the magnetic core is ZS157125 sendust, and the core operational amplifier of the amplifier circuit adopts the OPA313 single-supply operational amplifier.

Further, the filter system includes a third-order active low-pass filter and a third-order active high-pass filter; the third-order active low-pass filter and the third-order active high-pass filter are connected in parallel to the output end of the amplifier circuit.

Further, the core operational amplifiers of the third-order active low-pass filter and the third-order active high-pass filter are OPA313 single-supply operational amplifiers; the cut-off frequency of the third-order active low-pass filter is 1300Hz, and the third-order active high-pass filter The cutoff frequency of the device is 2700Hz.

Further, the auxiliary power supply system includes a large capacitor charging circuit, a BOOST boost circuit based on TPS61073; the large capacitor charging circuit includes a 10 ohm current limiting resistor, a low conduction voltage drop diode B10100 and a 2.2F capacitor, a 2.2F capacitor and a 10uf Tan capacitors are connected in parallel to reduce the output ripple. After the TPS61073-based BOOST boost circuit is connected in series with a large capacitor charging circuit, the input limit of the TPS61073-based BOOST boost circuit is above 1.8V, and the output voltage is constant at 5V.

Further, the single-chip processing and bluetooth transmission system includes a single-chip system and a bluetooth data transmission system, the single-chip system is connected to the output port of the filter system, the sending end of the bluetooth data sending system is connected to the IO port of the single-chip system, and the receiving end of the bluetooth data sending system is connected to the USB port of the upper computer; The auxiliary power supply system provides 5V voltage for the microcontroller system.

Furthermore, MSP430F5529 is used in the microcontroller system, and TICC2650 is used in the bluetooth data transmission system.

When this embodiment is implemented, as shown in FIG. 1 , the above-mentioned wireless current detection device includes: a current-type transformer system 1 , a filter system 2 , an auxiliary power supply system 3 , a single-chip microcomputer processing and a Bluetooth transmission system 4 . After the current transformer system 1 and the filter system 2 are connected in series to the alternating current output 5, the output of the filter system 2 is used as the input of the single-chip processing and the Bluetooth transmission system 4, and the output of the single-chip processing and the Bluetooth transmission system 4 is used as the system output , Auxiliary power supply system 3 as the peripheral part.

As shown in Figure 2, the current transformer system includes a toroidal transformer 11 with a turn ratio of primary and secondary coils of 1:14 and an amplifier circuit 12. The secondary coil is connected in parallel with a 100-ohm chip resistor to convert current to voltage, and one is processed by a single-chip microcomputer. And the 3.3V level provided by the Bluetooth transmission system 4 provides a 60mV bias level after being divided to raise the output voltage of the transformer above the GND level, and a single power supply operational amplifier powered by the auxiliary power supply system 3 is connected in series to The transformer output is used to amplify the signal.

As shown in FIG. 3( a ) and FIG. 3 ( b ), the filter system includes a third-order active low-pass filter 21 and a third-order active high-pass filter 22 . As shown in Figure 3(a), the cut-off frequency set by the third-order active low-pass filter 21 is 1300Hz, the attenuation of the second harmonic of 2000Hz is 10dB, and the attenuation of the third harmonic of 3000Hz is 20dB, and the current signal is filtered by this After the filter, the fundamental wave can pass through basically without attenuation, but with some attenuation, the amplitude will be 0.3 of the original. The third harmonic is basically filtered out. The output signal can be processed by the single-chip microcomputer and sampled by the bluetooth transmission system 4 . As shown in Figure 3(b), the cut-off frequency set by the third-order active high-pass filter 22 is 2700Hz, the attenuation of the second harmonic of 2000Hz is 10dB, and the attenuation of the fundamental wave and DC bias of 1000Hz is 20dB. After this filter, the positive half cycle of the third harmonic can pass through basically without attenuation. The output signal can be processed by the single-chip microcomputer and sampled by the bluetooth transmission system 4 .

As shown in FIG. 4 , the auxiliary power system includes a 2.2F large capacitor charging circuit 31 and a BOOST boost circuit 32 based on TPS61073. The large capacitor charging circuit 31 includes a 10 ohm current limiting resistor, a low conduction voltage drop diode B10100 and a 2.2F capacitor, the 2.2F capacitor is connected in parallel with a 10uf tank capacitor to reduce output ripple, and a BOOST boost circuit based on TPS61073 After 32 is connected in series to the 2.2F large capacitor charging circuit 31, the input limit of the BOOST boost circuit based on TPS61073 is above 1.8V, and the output voltage is constant at 5V

As shown in Figure 5, the single-chip microcomputer processing and bluetooth sending system comprises single-chip microcomputer system 41 and bluetooth data transmission system 42, and single-chip microcomputer system 41 power supply voltage is the +5V voltage that auxiliary power supply system 3 provides, and the function of single-chip microcomputer system 41 includes: 1. on-chip AD Three-channel AC sampling: respectively sample the input current signal, the output signal of the low-pass filter, and the output signal of the high-pass filter. 2. Carry out power calculation, through the total signal power = fundamental wave power + second harmonic power + third harmonic power, the amplitude value of the second harmonic can be calculated, so that the fundamental wave signal IA, the second harmonic signal IB , the amplitude value of the third harmonic signal IC is calculated. The Bluetooth data sending system includes a sending end and a receiving end, the sending end is connected to the IO port of the single-chip microcomputer, and the receiving end is connected to the USB port of the host computer.

In this embodiment, a wireless current detection device can wirelessly measure an alternating current with an effective value of 10mA to 1.5A, and can measure the fundamental wave contained in the alternating current and the amplitude value of the second and third harmonics, and the system power consumption is low. The output is stable and accurate, and can be calibrated manually, and displayed in real time through the host computer.

It should be understood that the parts not described in detail in this specification belong to the prior art.

Although the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, those of ordinary skill in the art should understand that these are only examples, and various variations or modifications can be made to these embodiments without departing from the principles of the present invention. principle and substance. The scope of the invention is limited only by the appended claims.

Claims (8)

1. a kind of wireless current sensing means, including alternating current is exported and host computer, it is characterised in that also mutual including current mode Sensor system, filter system, secondary power system, single-chip microcomputer process and bluetooth send system；Current mode transformer system, filter Ripple device Cascade System accesses alternating current output, and filter system sends the input phase of system with single-chip microcomputer process and bluetooth Even, single-chip microcomputer process and bluetooth send the outfan connection host computer of system, and secondary power system connects respectively current mode mutual inductance Device system, filter system and single-chip microcomputer are processed and bluetooth sends system.

2. current sensing means as claimed in claim 1 wireless, it is characterised in that current mode transformer system includes transformation Device, amplifier circuit；Transformer inputs connection alternating current output, amplifier circuit connection transformer outfan.

3. current sensing means as claimed in claim 2 wireless, it is characterised in that transformer primary secondary coil turn ratio is 1： 14, magnetic core is ZS157125 ferrum sial, and amplifier circuit its main operational amplifier adopts OPA313 single supply operational amplifiers.

4. current sensing means as claimed in claim 2 wireless, it is characterised in that filter system includes the active low pass of three ranks Wave filter and three rank active high-pass filters；Access after three rank active low-pass filters are in parallel with three rank active high-pass filters and put Big device circuit output end.

5. current sensing means as claimed in claim 4 wireless, it is characterised in that three rank active low-pass filters and three ranks have The core amplifier of source high pass filter selects OPA313 single supply ops；The cut-off frequency of three rank active low-pass filters is 1300Hz, the cut-off frequency of three rank active high-pass filters is 2700Hz.

6. current sensing means as claimed in claim 1 wireless, it is characterised in that secondary power system includes that bulky capacitor charges Circuit, the BOOST booster circuits based on TPS61073；Bulky capacitor charging circuit includes 10 ohm of current-limiting resistances, low conducting Pressure drop diode B10100 and 2.2F electric capacity, 2.2F electric capacity is in parallel with the smooth electric capacity of a 10uf to reduce output ripple, is based on The BOOST booster circuits series connection of TPS61073 is accessed after bulky capacitor charging circuit, the BOOST booster circuits based on TPS61073 Input is limited to more than 1.8V, and output voltage is constant for 5V.

7. current sensing means as claimed in claim 6 wireless, it is characterised in that single-chip microcomputer process and bluetooth send system bag Include Single Chip Microcomputer (SCM) system and blue-teeth data sends system, Single Chip Microcomputer (SCM) system connection filter system delivery outlet, blue-teeth data sends system System transmitting terminal connection Single Chip Microcomputer (SCM) system I/O port, blue-teeth data sends system receiving terminal connection host computer USB port；Secondary power system 5V voltages are provided for Single Chip Microcomputer (SCM) system.

8. current sensing means as claimed in claim 7 wireless, it is characterised in that Single Chip Microcomputer (SCM) system adopts MSP430F5529, Blue-teeth data sends system and adopts TICC2650.