A power / signal synchronous transmission system and method for intrinsically safe power supply

Abstract

The present invention discloses a synchronous power / signal transmission system and method for an intrinsically safe power supply, wherein the transmission system comprises a synchronous buck chopper circuit 1, a synchronous buck chopper circuit 2, a signal generating system 1, a driving circuit 1, a signal demodulation system 1, a signal generating system 2, a driving circuit 2, and a signal demodulation system 2. The present invention adopts a new signal transmission control method to generate ripples on the load, and realizes bidirectional transmission of signals by modulating and demodulating the voltage ripples generated on the load. When the switch tube is turned off, the signal can still be transmitted, which improves the accuracy and speed of signal transmission. The load ripple is still small during the signal transmission process, and will not have a significant impact on the transmission of energy.

Description

Technical Field

[0001] The present invention relates to the technical field of signal transmission, and in particular to an electric energy / signal synchronous transmission system and method for an intrinsically safe power supply. Background Art

[0002] At present, in order to realize the synchronous transmission of energy signals in DC power supply systems, the research directions at home and abroad are divided into wired communication and wireless communication. As a kind of wired communication, power line communication does not require additional communication cables, so the cost and system complexity are relatively low. However, the ripple modulation method currently used to realize power line communication cannot transmit signals when the switch tube is turned off during signal transmission. Therefore, the signal transmission speed is slow and the accuracy is low. It is also easily interfered by environmental noise and is not suitable for working environments such as mines and oil fields. In this type of research, the energy signal synchronous transmission system developed based on traditional converters mostly uses Schottky diodes as freewheeling paths. However, the Schottky diode has a high on-resistance, which will produce a large conduction loss and reduce the transmission efficiency of the buck chopper circuit.

[0003] At present, most intrinsically safe power supplies can only realize one-way signal transmission. However, in working environments such as mines and oil wells where dangerous explosive gases are easily generated, there is an urgent need for power supply equipment that can realize two-way signal transmission to carry out two-way communication and improve the ability of intelligent systems to coordinate with each other. Currently, most of the two-way communication can be realized by wireless communication. However, wireless signals are easily interfered in mines, which greatly reduces the reliability.

[0004] Intrinsically safe power supply is an electrical system that will not cause explosion when the circuit is working under normal conditions or when a fault occurs. Intrinsically safe power supply starts from the root, limiting the potential spark energy and the heating temperature of the wire and component surface to below the ignition temperature of the specified gas mixture, which essentially improves the safety level of the system. Summary of the invention

[0005] The object of the present invention is to provide a power / signal synchronous transmission system and method for an intrinsically safe power supply to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The invention discloses an electric energy / signal synchronous transmission system for an intrinsically safe power supply, comprising a first synchronous buck chopper circuit, a second synchronous buck chopper circuit, a first signal generating system, a first driving circuit, a first signal demodulation system, a second signal generating system, a second driving circuit, and a second signal demodulation system. The first signal generating system is connected to the first synchronous buck chopper circuit via the first driving circuit, the first synchronous buck chopper circuit is also connected to the first signal demodulation system and the second synchronous buck chopper circuit, the second signal generating system is connected to the second synchronous buck chopper circuit via the second driving circuit, and the second synchronous buck chopper circuit is also connected to the second signal demodulation system.

[0008] As a further technical solution of the present invention: the signal generating system 1 and the signal generating system 2 have the same structure, the signal generating system 1 includes a signal generator 1, a control pulse generator 1 and a control pulse selector 1, and the control pulse selector 1 is respectively connected to the signal generator 1 and the control pulse generator 1.

[0009] As a further technical solution of the present invention: the drive circuit 1 and the drive circuit 2 have the same structure, and the drive circuit 1 includes a pulse generator 1, an AND gate 1, an AND gate 2, an AND gate 3, a NOT gate 1, a NOT gate 2 and a NOT gate 3, the two input ends of the AND gate 1 are respectively connected to the control pulse selector 1 and the pulse generator 1, the output end of the AND gate 1 is connected to the input end of the NOT gate 2 and the switch tube Q1, the input end of the NOT gate 1 is connected to the pulse generator 1, the output end of the NOT gate 2 is connected to an input end of the AND gate 2, the other input end of the AND gate 2 is connected to the control pulse selector 1, the output end of the AND gate 2 is connected to the input end of the NOT gate 3 and the switch tube Q2, the two input ends of the AND gate 3 are respectively connected to the output end of the NOT gate 2 and the output end of the NOT gate 3, and the output end of the AND gate 3 is connected to the switch tube Q3.

[0010] As a further technical solution of the present invention: the structures of the synchronous buck chopper circuit 1 and the synchronous buck chopper circuit 2 are the same. The synchronous buck chopper circuit 1 includes a diode D1, a switch tube Q1, a power supply DC1, a switch tube Q2, a switch tube Q3, an inductor L1, a capacitor C1 and a resistor R1. The gate of the switch tube Q1 is connected to the driving circuit 1, the drain of the switch tube Q1 is connected to the positive electrode of the power supply DC1 and the cathode of the diode D1, the source of the switch tube Q1 is connected to the anode of the diode D1, the drain of the switch tube Q2, the cathode of the diode D2, the source of the switch tube Q3 and the inductor L1, the gate of the switch tube Q2 is connected to the driving circuit 1, the gate of the switch tube Q2 is connected to the driving circuit 1, the other end of the inductor L1 is connected to the capacitor C1, the resistor R1, the drain of the switch tube Q3, the resistor R2 and the signal demodulation system 1, and the other end of the capacitor C1 is connected to the other end of the resistor R1, the source of the switch tube Q2, the negative electrode of the power supply DC1 and the synchronous buck chopper circuit 2.

[0011] As a further technical solution of the present invention: the signal demodulation system 1 and the signal demodulation system 2 have the same structure, the signal demodulation system 1 includes a sampling module 1, a filter 1, and an FFT demodulation module 1, the sampling module 1 is connected to the filter 1, the filter 1 is connected to the FFT demodulation module 1, and the FFT demodulation module 1 outputs a signal 1.

[0012] A method for synchronous transmission of electric energy / signal for intrinsically safe power supply adopts the above system, and the specific method is as follows: signal generation system 1 and signal generation system 2 are used to generate signals to be sent. Driving circuit 1 controls field effect transistor Q1 and field effect transistor Q2 to generate signal ripples on the load and supply power to the load by sending trigger pulse 1 and trigger pulse 2, and controls field effect transistor Q3 as a freewheeling circuit by sending trigger pulse 3; driving circuit 2 controls field effect transistor Q4 and field effect transistor Q5 to generate signal ripples on the load and supply power to the load by sending trigger pulse 4 and trigger pulse 5, and controls field effect transistor Q6 as a freewheeling circuit by sending trigger pulse 6.

[0013] As a further technical solution of the present invention: the signal demodulation system 1 and the signal demodulation system 2 demodulate the signal by detecting the ripple signal on the load, restore it to the original signal, and realize two-way transmission of the signal.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention adopts a new signal transmission control method, generates ripples on the load, and realizes bidirectional transmission of signals by modulating and demodulating the voltage ripples generated on the load. The signal can still be transmitted when the switch tube is turned off, which improves the accuracy and speed of signal transmission. The load ripple is still small during signal transmission and will not have a significant impact on energy transmission. It improves the situation that the signal can only be transmitted in one direction in the intrinsically safe power supply before, and meets the urgent needs of special environments such as mines and oil fields for bidirectional signal communication. Since communication is achieved through power lines instead of wireless communication, the signal is not easily interfered with and maliciously attacked, and has strong reliability. And because the energy signal shares the same transmission path, compared with the one-way transmission of the signal, there is no increase in excessive signal transmission devices, the system complexity is relatively small, and the cost is low.

[0016] By limiting the energy of the circuit, the spark energy that may appear in the system is limited to below the specified energy of the ignitable mixed gas, and the surface temperature of components such as the switching tube power supply and wires in the system is limited to below the ignition temperature of the gas, thereby achieving an intrinsically safe function. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a circuit topology diagram of the present invention.

[0018] Figure 2It is a schematic diagram of a signal generating system 1 and a driving circuit 1.

[0019] Figure 3 It is the schematic diagram of the signal generating system 2 and the driving circuit 2.

[0020] Figure 4 is a schematic diagram of the signal demodulation system 1.

[0021] Figure 5 It is a schematic diagram of the signal demodulation system 2.

[0022] Figure 6 This is a schematic diagram of the trigger pulses of the switch tubes Q1, Q2, and Q3. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] like Figure 1 As shown, a synchronous power / signal transmission system for an intrinsically safe power supply includes a synchronous buck chopper circuit 1, a synchronous buck chopper circuit 2, a signal generating system 1, a driving circuit 1, a signal demodulation system 1, a signal generating system 2, a driving circuit 2, and a signal demodulation system 2. The signal generating system 1 is connected to the synchronous buck chopper circuit 1 through the driving circuit 1, and the synchronous buck chopper circuit 1 is also connected to the signal demodulation system 1 and the synchronous buck chopper circuit 2. The signal generating system 2 is connected to the synchronous buck chopper circuit 2 through the driving circuit 2, and the synchronous buck chopper circuit 2 is also connected to the signal demodulation system 2.

[0025] like Figure 2 As shown, signal generating system 1 and signal generating system 2 have the same structure. Signal generating system 1 includes signal generator 1, control pulse generator 1 and control pulse selector 1. Control pulse selector 1 is respectively connected to signal generator 1 and control pulse generator 1.

[0026] The drive circuit 1 and the drive circuit 2 have the same structure. The drive circuit 1 includes a pulse generator 1, an AND gate 1, an AND gate 2, an AND gate 3, a NOT gate 1, a NOT gate 2 and a NOT gate 3. The two input ends of the AND gate 1 are respectively connected to the control pulse selector 1 and the pulse generator 1, the output end of the AND gate 1 is connected to the input end of the NOT gate 2 and the switch tube Q1, the input end of the NOT gate 1 is connected to the pulse generator 1, the output end of the NOT gate 2 is connected to an input end of the AND gate 2, the other input end of the AND gate 2 is connected to the control pulse selector 1, the output end of the AND gate 2 is connected to the input end of the NOT gate 3 and the switch tube Q2, the two input ends of the AND gate 3 are respectively connected to the output end of the NOT gate 2 and the output end of the NOT gate 3, and the output end of the AND gate 3 is connected to the switch tube Q3.

[0027] like Figure 3 As shown, the synchronous buck chopper circuit 1 and the synchronous buck chopper circuit 2 have the same structure. The synchronous buck chopper circuit 1 includes a diode D1, a switch tube Q1, a power supply DC1, a switch tube Q2, a switch tube Q3, an inductor L1, a capacitor C1 and a resistor R1. The gate of the switch tube Q1 is connected to the driving circuit 1, the drain of the switch tube Q1 is connected to the positive electrode of the power supply DC1 and the cathode of the diode D1, the source of the switch tube Q1 is connected to the anode of the diode D1, the drain of the switch tube Q2, the cathode of the diode D2, the source of the switch tube Q3 and the inductor L1, the gate of the switch tube Q2 is connected to the driving circuit 1, the gate of the switch tube Q2 is connected to the driving circuit 1, the other end of the inductor L1 is connected to the capacitor C1, the resistor R1, the drain of the switch tube Q3, the resistor R2 and the signal demodulation system 1, and the other end of the capacitor C1 is connected to the other end of the resistor R1, the source of the switch tube Q2, the negative electrode of the power supply DC1 and the synchronous buck chopper circuit 2.

[0028] like Figure 5 As shown, signal demodulation system 1 and signal demodulation system 2 have the same structure. Signal demodulation system 1 includes sampling module 1, filter 1, and FFT demodulation module 1. Sampling module 1 is connected to filter 1, filter 1 is connected to FFT demodulation module 1, and FFT demodulation module 1 outputs signal 1.

[0029] The schematic diagram of the signal generation system and driving circuit is shown in the figure below: Figure 2 and Figure 3 As shown, the signal sending method is as follows.

[0030] When the field effect tube Q2 is turned off, the field effect tube Q1 adopts high-frequency chopping. The on and off of the field effect tube Q1 at different frequencies will induce sinusoidal ripple signals with different amplitudes and frequencies on the load voltage. The signal can be transmitted through different ripples. At this time, Q2 is always in the off state. When Q1 is turned off at the same time, the inductor current cannot change suddenly, and the inductor current continues to flow through Q3.

[0031] When the FET Q1 is turned off, the inductor current continues to flow through the FET Q2, and the FET Q2 continues to switch using high-frequency chopping. When the switching frequency of the FET Q2 is different, it will induce sinusoidal ripple signals of different frequencies on the load voltage, so it can be used to transmit signals. At this time, Q1 is always in the off state, and when Q2 is turned off at the same time, the inductor current cannot change suddenly, so the inductor current continues to flow through Q3. The trigger pulse waveform is as follows: Figure 6 shown.

[0032] Since both FET Q1 and FET Q2 can transmit signals by switching, the signal transmission time of FET Q1 and the signal transmission time of FET Q2 are taken as a large switching cycle. Since different switching frequencies will induce different sinusoidal ripple signals on the load, the entire large switching cycle will also induce a sinusoidal ripple signal on the load, so the signal ripples generated by FET Q1 and FET Q2 are both signal ripples superimposed on the reference voltage and the ripples generated by the large switching cycle.

[0033] The control method of the field effect transistors Q4, Q5, and Q6 in the second synchronous buck chopper circuit is similar to this.

[0034] The corresponding ripple expression generated by different switching frequencies of the field effect tube on the load is:

[0035]

[0036] Therefore, sending a 0 / 1 signal requires generating two signals of different frequencies. Since bidirectional synchronous transmission of the signal is required, four signals of different frequencies need to be generated.

[0037] Set the signal generation system 1 to use a frequency of 300kHz when generating signal 1 and a frequency of 150kHz when generating signal 0; set the signal generation system 2 to use a frequency of 50kHz when generating signal 1 and a frequency of 20kHz when generating signal 0. Use the signal generator to connect the control pulse selector to select PWM waves of different frequencies so as to generate ripples of corresponding frequencies on the load.

[0038] The signal transmission time of field effect transistor Q1 and field effect transistor Q4 in one cycle is set to 32.5 microseconds, and the shutdown time is set to 22.5 microseconds; the signal transmission time of field effect transistor Q2 and field effect transistor Q5 in one cycle is set to 22.5 microseconds, and the shutdown time is set to 32.5 microseconds.

[0039] The schematic diagram of the signal demodulation system is as follows: Figure 4 As shown, the signal demodulation method is as follows.

[0040] In the signal demodulation system 1, the voltage signal of R1 collected is first input into the high-pass filter to filter out the low-frequency signal generated by the signal generation system 2. The filtered signal is subjected to the fast Fourier transform, and the original signal generated by the signal generation system 1 can be obtained after taking the modulus. In the signal demodulation system 2, the voltage signal of R2 collected is first input into the low-pass filter to filter out the high-frequency signal generated by the signal generation system 1, and then the same algorithm can be used to demodulate the original signal generated by the signal generation system 2. This algorithm can be implemented by DSP or single-chip microcomputer (such as stm32).

[0041] The energy transfer mode of the present invention is as follows.

[0042] From the circuit theory knowledge, we know that the output voltage of the step-down chopper circuit can be calculated by the following formula:

[0043]

[0044] Since the trigger pulse duty cycle of the field effect tube Q1 is 95% when transmitting a signal, it can be approximately considered that the field effect tube Q1 is in a continuously turned-on state at this time. Therefore, the output voltage calculation formula of the DC power supply after step-down chopping is:

[0045]

[0046] Where E is the DC voltage at the input side, t off is the turn-off time of the field effect tube Q1, and T is the sum of the turn-off time of the field effect tube Q1 and the time of high-frequency chopping signal transmission.

[0047] The change in the inductor current within one cycle is 0, so there will be no low-frequency oscillation on the load, and the ripple is small, which also lays the foundation for signal transmission through ripple. When the field effect tube Q1 is turned on, the inductor current rises to charge the load and capacitor; when the field effect tube Q1 is turned off, the inductor current continues to flow, and the inductor and capacitor supply power to the load at the same time. When the inductor and capacitor values ​​are relatively large, the load voltage will hardly drop after the switch tube is turned off compared to when the switch tube is turned on.

[0048] The spark discharge phenomenon in the step-down chopper circuit is generally caused by a short circuit of the capacitor or an open circuit of the inductor, so the energy of the capacitor and inductor needs to be limited. When the maximum current flowing through the inductor is lower than the minimum ignition current and the capacitor voltage is lower than the minimum ignition voltage, the intrinsic safety characteristics of the circuit are guaranteed.

[0049] When the capacitor is short-circuited, the energy of the spark generated by the capacitor is determined by the sum of the maximum energy stored by the inductor and the maximum energy stored by the capacitor. When the safety factor K is 1.5-2, it can be seen from the minimum ignition current curve of the capacitive circuit that when C B >C e The converter meets the requirements of intrinsic safety.

[0050] When the inductor is open-circuited, the energy of the spark generated by the inductor is determined by the current flowing through the inductor. When the safety factor K is 1.5-2, it can be seen from the minimum ignition current curve of the inductive circuit that when L B >L, the converter meets the requirements of intrinsic safety.

[0051] Therefore, the converter as a whole meets the requirements of intrinsic safety.

[0052] Embodiment 2, based on the embodiment, this design also discloses a method for synchronous transmission of electric energy / signal for intrinsically safe power supply, using the above-mentioned system, the specific method is as follows: signal generation system 1 and signal generation system 2 are used to generate signals to be sent. Driving circuit 1 controls field effect transistor Q1 and field effect transistor Q2 to generate signal ripples on the load and power the load by sending trigger pulse 1 and trigger pulse 2, and controls field effect transistor Q3 as a freewheeling circuit by sending trigger pulse 3; driving circuit 2 controls field effect transistor Q4 and field effect transistor Q5 to generate signal ripples on the load and power the load by sending trigger pulse 4 and trigger pulse 5, and controls field effect transistor Q6 as a freewheeling circuit by sending trigger pulse 6. Signal demodulation system 1 and signal demodulation system 2 demodulate the signal by detecting the ripple signal on the load, restore it to the original signal, and realize two-way transmission of the signal.

[0053] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0054] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A power / signal synchronous transmission system for intrinsically safe power supply, characterized in that: It includes a synchronous buck chopper circuit 1, a synchronous buck chopper circuit 2, a signal generating system 1, a driving circuit 1, a signal demodulation system 1, a signal generating system 2, a driving circuit 2, and a signal demodulation system 2. The signal generating system 1 is connected to the synchronous buck chopper circuit 1 through the driving circuit 1, the synchronous buck chopper circuit 1 is also connected to the signal demodulation system 1 and the synchronous buck chopper circuit 2, the signal generating system 2 is connected to the synchronous buck chopper circuit 2 through the driving circuit 2, and the synchronous buck chopper circuit 2 is also connected to the signal demodulation system 2; The drive circuit 1 and the drive circuit 2 have the same structure. The drive circuit 1 includes a pulse generator 1, an AND gate 1, an AND gate 2, an AND gate 3, a NOT gate 1, a NOT gate 2 and a NOT gate 3. The two input ends of the AND gate 1 are respectively connected to the control pulse selector 1 and the pulse generator 1, the output end of the AND gate 1 is connected to the input end of the NOT gate 2 and the switch tube Q1, the input end of the NOT gate 1 is connected to the pulse generator 1, the output end of the NOT gate 2 is connected to an input end of the AND gate 2, the other input end of the AND gate 2 is connected to the control pulse selector 1, the output end of the AND gate 2 is connected to the input end of the NOT gate 3 and the switch tube Q2, the two input ends of the AND gate 3 are respectively connected to the output end of the NOT gate 2 and the output end of the NOT gate 3, and the output end of the AND gate 3 is connected to the switch tube Q3; The synchronous buck chopper circuit 1 and the synchronous buck chopper circuit 2 have the same structure. The synchronous buck chopper circuit 1 includes a diode D1, a switch tube Q1, a power supply DC1, a switch tube Q2, a switch tube Q3, an inductor L1, a capacitor C1 and a resistor R1. The gate of the switch tube Q1 is connected to the driving circuit 1, the drain of the switch tube Q1 is connected to the positive electrode of the power supply DC1 and the cathode of the diode D1, the source of the switch tube Q1 is connected to the anode of the diode D1, the drain of the switch tube Q2, the cathode of the diode D2, the source of the switch tube Q3 and the inductor L1, the gate of the switch tube Q2 is connected to the driving circuit 1, the gate of the switch tube Q2 is connected to the driving circuit 1, the other end of the inductor L1 is connected to the capacitor C1, the resistor R1, the drain of the switch tube Q3, the resistor R2 and the signal demodulation system 1, and the other end of the capacitor C1 is connected to the other end of the resistor R1, the source of the switch tube Q2, the negative electrode of the power supply DC1 and the synchronous buck chopper circuit 2.

2. The electric energy / signal synchronous transmission system for intrinsically safe power supply according to claim 1, characterized in that: The signal generating system 1 and the signal generating system 2 have the same structure. The signal generating system 1 includes a signal generator 1, a control pulse generator 1 and a control pulse selector 1. The control pulse selector 1 is respectively connected to the signal generator 1 and the control pulse generator 1.

3. The electric energy / signal synchronous transmission system for intrinsically safe power supply according to claim 1, characterized in that: The signal demodulation system 1 and the signal demodulation system 2 have the same structure. The signal demodulation system 1 includes a sampling module 1, a filter 1, and an FFT demodulation module 1. The sampling module 1 is connected to the filter 1, the filter 1 is connected to the FFT demodulation module 1, and the FFT demodulation module 1 outputs a signal 1.

4. A method for synchronous transmission of electric energy / signal for intrinsically safe power supply, characterized in that: A system as described in any one of claims 1 to 3 is adopted, and the specific method is as follows: signal generating system 1 and signal generating system 2 are used to generate signals to be sent, and drive circuit 1 controls field effect transistor Q1 and field effect transistor Q2 to generate signal ripples on the load and power the load by sending trigger pulse 1 and trigger pulse 2, and controls field effect transistor Q3 as a freewheeling circuit by sending trigger pulse 3; drive circuit 2 controls field effect transistor Q4 and field effect transistor Q5 to generate signal ripples on the load and power the load by sending trigger pulse 4 and trigger pulse 5, and controls field effect transistor Q6 as a freewheeling circuit by sending trigger pulse 6.

5. The method for synchronous transmission of electric energy / signal for intrinsically safe power supply according to claim 4, characterized in that: The signal demodulation system 1 and the signal demodulation system 2 demodulate the signal by detecting the ripple signal on the load, restore it to the original signal, and realize the two-way transmission of the signal.

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