Digital power communication power supply suitable for information support of multi-node alternating-current micro-grid and control method of digital power communication power supply

Abstract

The invention discloses a digital power communication power supply suitable for multi-node AC micro-grid information support and a control method thereof, the digital power communication power supply comprises an uncontrollable rectifier bridge module, an LC resonance amplification module and a single-stage Boost-Flyback module, and the communication method comprises a power information integrated regulation and control mode and a communication signal demodulation mode. The digital power communication power supply can work in one of three node modes through a control switch k1 and a control switch k2, a node transmits a communication signal to a power line in a signal sending node mode, a node signal enhancement coefficient G is introduced in a signal receiving node mode, and the communication current intensity can be greatly enhanced. According to the digital power communication power supply, on the premise that a power supply circuit and a hardware demodulation circuit do not need to be additionally designed, the problem that communication is limited in a multi-node and long-distance alternating-current micro-grid can be effectively solved, and information support is provided for multiple inverter nodes of the alternating-current micro-grid.

Description

Technical Field

[0001] The present invention relates to the fields of power electronics technology and communication technology, and in particular to a digital power communication power supply suitable for multi-node AC microgrid information support and a control method thereof. Background Art

[0002] At present, the communication methods commonly used for energy management and control of multi-node AC microgrids mainly include LAN communication, optical fiber communication and power carrier communication. Among them, wired communication requires additional communication lines and is easily damaged in some remote areas. Power carrier communication relies on power lines to transmit information, without the need for additional lines, but requires additional hardware circuit demodulation and power supply. In addition, in multi-node AC microgrids, the communication strength of the power carrier communication signal allocated to each node is the same and weak, which can easily cause problems in communication distance and stability. Therefore, the current communication methods used for multi-node AC microgrids still have great limitations in many application scenarios. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a digital power communication power supply and a control method thereof suitable for information support of a multi-node AC microgrid in view of the deficiencies in the prior art, so as to effectively solve the communication limitation problem existing in a multi-node and long-distance AC microgrid.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a digital power communication power supply suitable for multi-node AC microgrid information support, comprising an uncontrollable rectifier bridge module, an LC resonant amplifier module, and a single-stage Boost-Flyback module connected in sequence;

[0005] The uncontrolled rectifier bridge module comprises two parallel bridge arms, and the input sides of the two parallel bridge arms are connected to any phase of a three-phase AC bus;

[0006] The LC resonance amplification module includes a resonance amplification inductor connected to an output end of the uncontrollable rectifier bridge module, the resonance amplification inductor is connected to one end of the resonance amplification capacitor, and the other end of the resonance amplification capacitor is connected to the other output end of the uncontrollable rectifier bridge module;

[0007] The single-stage Boost-Flyback module includes an inductor, one end of which is connected to the resonant amplifying inductor, and the other end is connected to the anodes of two parallel diodes, the cathode of the first diode is connected to the drain of the switching tube and one end of the excitation inductor, the source of the switching tube is connected to the output of the uncontrolled rectifier bridge module and one end of the first capacitor, and the other end of the capacitor is connected to the cathode of the second diode and the other end of the excitation inductor; the excitation inductor is connected in parallel with the primary winding of the high-frequency transformer; the secondary winding of the high-frequency transformer is connected in parallel with the second capacitor; the anode of the second diode is connected to the other end of the secondary winding of the high-frequency transformer.

[0008] Compared with the auxiliary power supply of the traditional inverter, the present invention can not only provide auxiliary power supply for the inside of the inverter, but also add a resonant amplifying inductor and a resonant amplifying capacitor, so that the digital power communication power supply itself has the ability to send and receive information.

[0009] The present invention provides a control method for the above communication power supply, comprising the following steps:

[0010] The reference output voltage value v out_ref With the second capacitor C 3 The output voltage v out The output voltage error value is obtained by subtracting and then compared with the AC input voltage v ac The absolute value of the synchronous sinusoidal signal |sinω i t|, and get the power reference current value i ref2 , where ω i is the grid angular frequency;

[0011] Use the binary baseband data signal a(t) to obtain the modulated signal carrier s a (t)=(2a(t)-1)msinω s t, and then through the switch k 1 Get the communication reference current value i ref1 ; Where m is the signal carrier amplitude, ω s is the signal carrier angular frequency;

[0012] Power reference current value i ref2 and the communication reference current value i ref1 After adding, we get the reference current value i ref The reference current value i ref The absolute value of the input current sampled |i in | make a difference, and the difference is passed through the PI controller to obtain the first result; the node signal enhancement coefficient G is controlled by the switch k 2 The duty cycle signal d is then multiplied with the first result to obtain a duty cycle signal d; the duty cycle signal d is compared with the triangular carrier to obtain a switch tube drive signal g(t). The node signal enhancement coefficient G has a value range of 0<G<0.1, and in the present invention, G=0.05.

[0013] The coefficient G can reduce the open-loop gain of the current inner loop in the control method, so that the response speed of the digital power communication power supply slows down, which is reflected in the reduction of input impedance. The calculation formula of the open-loop gain is: K OL =G(K p +K i / s)G o (s), where K p , K iare the proportional coefficient and integral coefficient of the PI controller, G o (s) is the transfer function from digital power communication power supply control to output.

[0014] The switch k 1 and k 2 Enables digital power communication power supply to work in three node modes:

[0015] When k 1 =1,k 2 =0, the communication reference current value i ref1 =s a (t), and the node signal enhancement coefficient G is not added, and the digital power communication power supply works in the sending node mode;

[0016] When k 1 =0,k 2 =1, the communication reference current value i ref1 =0, and the node signal enhancement coefficient G is added, and the digital power communication power supply works in the receiving node mode;

[0017] When k 1 =0,k 2 =0, the communication reference current value i ref1 =0, and the node signal enhancement coefficient G is not added, and the digital power communication power supply operates in the idle node mode.

[0018] The present invention uses a digital power communication power supply as a communication carrier without adding additional communication lines. By switching the working node mode, the nodes in the AC microgrid that need to send information work in the sending node mode; the nodes that need to receive information work in the receiving node mode; and the remaining nodes work in the idle node mode. The node signal enhancement coefficient G is added to the receiving node control, so that its input impedance is lower than that of other nodes, and more communication current will be received by the receiving node, thereby effectively solving the problem that the communication current of each node in the multi-node AC microgrid is the same and weak, and the communication is more reliable.

[0019] The method of the present invention also includes a communication signal demodulation part, and the communication signal demodulation part includes:

[0020] Sampling receiving node digital power communication power input current i in , the input current i in After passing through the bandpass filter BPF, the communication current component i with the same frequency as the signal carrier is obtained. inc ;

[0021] The communication current component i inc With the signal carrier msinω s t and then multiplied by the input voltage v acThe symbolic function v sign Multiply, the result is s b (t) is obtained by passing through a low-pass filter LPF L (t);

[0022] For L (t) performs sampling decision to obtain a binary output signal s(t); the sampling decision implementation process includes: detecting the positive and negative of the intermediate signal in each code element, when it is greater than 0, s(t) is 1, and when it is less than 0, s(t) is 0.

[0023] The signal demodulation method of the present invention utilizes signal carrier demodulation, which can restore the signal more accurately, so that the receiving node can also work effectively in a low signal-to-noise ratio environment such as a multi-node, long-distance, etc.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. Compared with the auxiliary power supply of the traditional inverter, the present invention can not only provide auxiliary power supply for the inverter, but also add resonant amplifying inductance and resonant amplifying capacitor, so that the digital power communication power supply itself has the ability to send and receive information.

[0026] 2. The present invention effectively solves the problem of limited communication in multi-node, long-distance AC microgrids without adding additional communication lines. Increasing the node signal enhancement coefficient G enables more communication currents to be received by the receiving nodes, making communication more reliable.

[0027] 3. The present invention is embedded in the inverter and is directly powered by a single-phase AC power grid, without the need to design additional power supply circuits and hardware demodulation circuits, thus reducing design costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of an application of a digital power communication power supply according to an embodiment of the present invention in a multi-node AC microgrid;

[0029] Figure 2 A schematic diagram of the structure of a digital power communication power supply according to an embodiment of the present invention;

[0030] Figure 3 This is a block diagram of integrated control of power information of a digital power communication power supply according to an embodiment of the present invention;

[0031] Figure 4 This is a control block diagram of a digital power communication power supply demodulation mode according to an embodiment of the present invention;

[0032] Figure 5 Schematic diagram of 4 digital power communication power supply nodes in different node modes;

[0033] Figure 6 for Figure 5 Schematic diagram of the digital power communication power supply receiving communication current waveform in the scenario;

[0034] Figure 7 for Figure 5 Schematic diagram of the comparison between the binary source code and the demodulated output waveform of the receiving node in the scenario. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0036] Example 1

[0037] This embodiment provides a digital power communication power supply suitable for multi-node AC microgrid information support, such as Figure 1 As shown, the multi-node AC microgrid of this embodiment includes a multi-node inverter; the inverter input terminal is connected to a multi-type DC power supply V DC The output end is connected to the three-phase AC bus; the digital power communication power supply is embedded in the inverter circuit design, and the output voltage provides auxiliary power supply for the inverter.

[0038] like Figure 2 As shown, the digital power communication power supply is embedded in the inverter circuit, including: an uncontrolled rectifier bridge module, an LC resonant amplifier module, and a single-stage Boost-Flyback module.

[0039] The uncontrolled rectifier bridge module includes four diodes D 1 , D 2 , D 3 , D 4 , diode D 1 The positive electrode of the diode D 3 The negative pole of the AC input is connected to ac The a terminal of diode D 2 The positive electrode of the diode D 4 The negative pole of the AC input is connected to ac The b terminal; the AC input v ac is the voltage of any phase of the three-phase AC bus.

[0040] The LC resonant amplifier module includes a resonant amplifier inductor L 1 , resonant amplifier inductor L 1 One end is connected to the output C of the uncontrolled rectifier bridge, and the other end is connected to the resonant amplifier capacitor C 1One end of the resonant amplifier capacitor C 1 The other end is connected to the output d end of the uncontrolled rectifier bridge.

[0041] The single-stage Boost-Flyback module includes an inductor L 2 , the inductance L 2 One end is connected to the resonant amplifier inductor L 1 , the other end is connected to diode D 5 and D 6 The positive electrode of the diode D 5 The negative pole is connected to the switch tube S 1 The drain and magnetizing inductance L m The source of the switch tube is connected to the output d end of the uncontrolled rectifier bridge module and the capacitor C 2 One end of the capacitor C 2 The other end of the diode is connected to the 6 The negative pole and the excitation inductance L m The other end is connected to the excitation inductance L m Connect in parallel with the primary winding of the high-frequency transformer; connect the same end of the secondary winding of the high-frequency transformer to the capacitor C 3 One side is connected, capacitor C 3 The other side of the diode D 7 Negative connection, diode D 7 The positive electrode is connected to the other end of the complex winding of the high-frequency transformer.

[0042] Digital power communication power supply can change the switch tube S through integrated power information control 1 The on-off process provides auxiliary power to the inverter while transmitting communication signals through the input side power line.

[0043] Example 2

[0044] like Figure 3 As shown, this embodiment proposes a power information integrated control method to change the switch tube S 1 During the on-off process, the digital power communication power supply not only provides auxiliary power supply to the inverter, but also transmits communication signals through the power lines.

[0045] A power information integrated control method changes the switch tube S 1 The specific steps of the on-off process include:

[0046] 1) Reference output voltage v out_ref With sampling capacitor C 3 The output voltage v out The output voltage error value is obtained by subtracting and then compared with the AC input voltage v ac The absolute value of the synchronous sinusoidal signal |sinω i t| multiply to get the power reference current value iref2 , where ω i is the grid angular frequency.

[0047] 2) The binary baseband data signal a(t) is multiplied by 2 and then subtracted by 1, and then multiplied by the sinusoidal signal carrier to obtain the modulated signal carrier s a (t)=(2a(t)-1)msinω s t, and then through the switch k 1 Get the communication reference current value i ref1 ; Where m is the signal carrier amplitude, ω s is the signal carrier frequency.

[0048] 3)i ref1 and i ref2 After adding, we get the reference current value i ref The reference current value i ref The absolute value of the input current sampled |i in | The first result is obtained after the difference is passed through the PI controller; the node signal enhancement coefficient G is controlled by the switch k 2 The duty cycle signal d is then multiplied with the first result to obtain the duty cycle signal d; the duty cycle signal d is compared with the triangular carrier to obtain the switch tube S 1 The driving signal g(t);

[0049] In order to facilitate the switching node mode of the digital power communication power supply, the present embodiment provides a control switch k 1 and k 2 The switching mode enables the digital power communication power supply to work in three node modes:

[0050] When k 1 =1,k 2 =0, the communication reference current value i ref1 =s a (t), and the node signal enhancement coefficient G is not added, the digital power communication power supply works in the sending node mode, at this time the digital power communication power supply injects a communication current with the same frequency as the signal carrier into the single-phase AC bus on the input side, and provides auxiliary power supply to the inverter at the same time;

[0051] When k 1 =0,k 2 =1, the communication reference current value i ref1 =0, and the node signal enhancement coefficient G is added, the digital power communication power supply works in the receiving node mode. At this time, the communication current intensity in the input current of the digital power communication power supply is large, it is easy to receive the communication signal, and at the same time provide auxiliary power supply to the inverter;

[0052] When k 1 =0,k 2 =0, the communication reference current value i ref1=0, and the node signal enhancement coefficient G is not added, the digital power communication power supply works in the idle node mode. At this time, the communication current intensity in the input current of the digital power communication power supply is weak, and it is not easy to receive the communication signal. At the same time, auxiliary power supply is provided to the inside of the inverter.

[0053] like Figure 4 As shown, this embodiment provides a communication signal demodulation method for a digital power communication power supply suitable for multi-node AC microgrid information support, and the specific steps are as follows:

[0054] 1) Sample the digital power communication power input current i of the receiving node in , the input current i in After passing through the bandpass filter BPF, the communication current component i with the same frequency as the signal carrier is obtained. inc ;

[0055] 2) The communication current component i inc With the signal carrier msinω s t and then multiplied by the input voltage v ac The symbolic function v sign Multiply, the result is s b (t) is obtained by passing through a low-pass filter LPF L (t).

[0056] 3) For s L (t) performs sampling judgment to obtain a binary output signal s(t). The sampling judgment detects the positive and negative of the intermediate signal in each code element, and outputs 1 when it is greater than 0, and outputs 0 when it is less than 0.

[0057] like Figure 5 As shown, this embodiment adopts a digital power communication power supply suitable for multi-node AC microgrid information support to form a 4-node communication network, and controls the switch k by a given 1 and k 2 Make the digital power communication power supply #1 work at the sending node, the digital power communication power supply #2 work at the receiving node, and the digital power communication power supply #3 and the digital power communication power supply #4 work at the idle node.

[0058] like Figure 6 As shown, in Figure 5 The communication current intensity of the receiving node in the communication network is 263% of that of the idle node. The high communication current intensity of the receiving node is beneficial to reliable communication in multi-node and long-distance AC microgrids.

[0059] like Figure 7 As shown, in this embodiment Figure 5The comparison between the demodulated output of the receiving node and the binary source code of the sending node in the communication network verifies the feasibility of the integrated power information control and demodulation method of this embodiment, and the communication method has a low bit error rate and strong communication reliability.

[0060] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0061] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A digital power communication power supply suitable for multi-node AC microgrid information support, characterized in that: It includes an uncontrollable rectifier bridge module, an LC resonant amplifier module, and a single-stage Boost-Flyback module connected in sequence; The uncontrolled rectifier bridge module comprises two parallel bridge arms, and the input sides of the two parallel bridge arms are connected to any phase of a three-phase AC bus; The LC resonance amplification module includes a resonance amplification inductor connected to an output end of the uncontrollable rectifier bridge module, the resonance amplification inductor is connected to one end of the resonance amplification capacitor, and the other end of the resonance amplification capacitor is connected to the other output end of the uncontrollable rectifier bridge module; The single-stage Boost-Flyback module includes an inductor, one end of which is connected to the resonant amplifying inductor, and the other end is connected to the anodes of two parallel diodes, the cathode of the first diode is connected to the drain of the switching tube and one end of the excitation inductor, the source of the switching tube is connected to the output of the uncontrolled rectifier bridge module and one end of the first capacitor, and the other end of the capacitor is connected to the cathode of the second diode and the other end of the excitation inductor; the excitation inductor is connected in parallel with the primary winding of the high-frequency transformer; the secondary winding of the high-frequency transformer is connected in parallel with the second capacitor; the anode of the second diode is connected to the other end of the secondary winding of the high-frequency transformer.

2. A method for controlling a communication power supply according to claim 1, characterized in that: The following steps are involved: The reference output voltage value v out_ref The output voltage v obtained at both ends of the second capacitor C3 out The output voltage error value is obtained by subtracting and then compared with the AC input voltage v ac The absolute value of the synchronous sinusoidal signal |sinω i t|, and get the power reference current value i ref2 , where ω i is the grid angular frequency; Use the binary baseband data signal a(t) to obtain the modulated signal carrier s a (t)=(2a(t)-1)msinω s t, and then obtain the communication reference current value i through switch k1 ref1 ; Where m is the signal carrier amplitude, ω s is the signal carrier angular frequency; Power reference current value i ref2 and the communication reference current value i ref1 After adding, we get the reference current value i ref The reference current value i ref The absolute value of the input current sampled |i in | is subtracted, and the difference is passed through a PI controller to obtain a first result; the node signal enhancement coefficient G is multiplied by the first result after passing through switch k2 to obtain a duty cycle signal d; the duty cycle signal d is compared with the triangular carrier to obtain a driving signal g(t) of the switch tube.

3. The method according to claim 2, characterized in that 0＜G＜0.1。 4. The method according to claim 2 or 3, characterized in that: G＝0.05。 5. The method according to claim 2, characterized in that: The switches k1 and k2 enable the digital power communication power supply to operate in three node modes: When k1=1, k2=0, the communication reference current value i ref1 =s a (t), and the node signal enhancement coefficient G is not added, and the digital power communication power supply works in the sending node mode; When k1=0, k2=1, the communication reference current value i ref1 =0, and the node signal enhancement coefficient G is added, and the digital power communication power supply works in the receiving node mode; When k1=0, k2=0, the communication reference current value i ref1 =0, and the node signal enhancement coefficient G is not added, and the digital power communication power supply operates in the idle node mode.

6. The method according to claim 2, characterized in that It also includes a communication signal demodulation part, and the communication signal demodulation part includes: Sampling receiving node digital power communication power input current i in , the input current i in After passing through the bandpass filter BPF, the communication current component i with the same frequency as the signal carrier is obtained. inc ; The communication current component i inc With the signal carrier msinω s t and then multiplied by the input voltage v ac The symbolic function v sign Multiply, the result is s b (t) is obtained by passing through a low-pass filter LPF L (t); For L (t) performs sampling decision to obtain a binary output signal s(t); the sampling decision implementation process includes: detecting the positive and negative of the intermediate signal in each code element, when it is greater than 0, s(t) is 1, and when it is less than 0, s(t) is 0.

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