Digital power communication power supply and control method suitable for multi-node ac microgrid information support

Abstract

The application discloses a digital power communication power supply suitable for information support of a multi-node alternating current microgrid 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 power information integrated regulation and control and a communication signal demodulation mode. The digital power communication power supply can work in one of three node modes by controlling switches k1 and k2. In the signal sending node mode, the node transmits a communication signal to a power line. In the signal receiving node mode, a node signal enhancement coefficient G is introduced, so that the communication current intensity can be greatly enhanced. The digital power communication power supply can effectively solve the communication limitation problem existing in the multi-node and long-distance alternating current microgrid without additionally designing a power supply circuit and a hardware demodulation circuit, and provides information support for the alternating current microgrid multi-inverter node.

Description

Technical Field

[0001] This invention relates to the fields of power electronics and communication technology, and in particular to a digital power communication power supply and its control method suitable for information support in multi-node AC microgrids. Background Technology

[0002] Currently, common communication methods used for energy management in multi-node AC microgrids include local area network (LAN) communication, fiber optic communication, and power line carrier communication. Wired communication requires additional communication lines and is susceptible to damage in remote areas. Power line carrier communication transmits information via power lines without requiring additional lines, but it does require additional hardware circuitry for demodulation and a power supply. Furthermore, in multi-node AC microgrids, the power line carrier communication signal strength distributed to each node is the same and relatively weak, easily leading to limitations in communication distance and stability. Therefore, current communication methods used in multi-node AC microgrids still have significant limitations in various 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 its control method suitable for information support in multi-node AC microgrids, which effectively solves the communication limitation problem in multi-node, long-distance AC microgrids, in order to address the shortcomings of the existing technology.

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

[0005] The uncontrollable rectifier bridge module includes two parallel bridge arms, and the input side of the two parallel bridge arms is connected to any one phase of the three-phase AC bus.

[0006] The LC resonant amplifier module includes a resonant amplification inductor connected to one output terminal of the uncontrolled rectifier bridge module, the resonant amplification inductor being connected to one end of a resonant amplification capacitor, and the other end of the resonant amplification capacitor being connected to the other output terminal of the uncontrolled rectifier bridge module.

[0007] The single-stage Boost-Flyback module includes an inductor. One end of the inductor is connected to the resonant amplifying inductor, and the other end is connected to the anode of two parallel diodes. The cathode of the first diode is connected to the drain of a switching transistor and one end of a magnetizing inductor. The source of the switching transistor is connected to the output of the uncontrolled rectifier bridge module and one end of a first capacitor. The other end of the capacitor is connected to the cathode of a second diode and the other end of the magnetizing inductor. The magnetizing inductor is connected in parallel with the primary winding of a 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 to the auxiliary power supply of traditional inverters, this invention not only provides auxiliary power supply to the inverter's internal components, but also adds a resonant amplifying inductor and a resonant amplifying capacitor, enabling the digital power communication power supply itself to have information transmission and reception capabilities.

[0009] This invention provides a control method for the above-mentioned communication power supply, comprising the following steps:

[0010] Reference output voltage value v out_ref The output voltage v obtained across the second capacitor C3 out The output voltage error value is obtained by subtraction, and after passing through the PI controller, it is compared with the AC input voltage. ac The absolute value of the synchronous sinusoidal signal |sinω i Multiplying by t| yields the power reference current value i. ref2 In the formula ω i The angular frequency of the power grid;

[0011] The modulated signal carrier s is obtained using the binary baseband data signal a(t). a (t)=(2a(t)-1)msinω s t, and then obtain the communication reference current value i through switch k1. ref1 In the formula, m is the amplitude of the signal carrier, and ω s The angular frequency of the signal carrier.

[0012] Power reference current value i ref2 and communication reference current value i ref1 The reference current value i is obtained by adding them together. ref The reference current value i ref The absolute value of the sampled input current |i in The difference is calculated, and the difference is passed through a PI controller to obtain a first result. The node signal enhancement coefficient G is passed through switch k2 and multiplied by the first result to obtain the duty cycle signal d. The duty cycle signal d is compared with a triangular carrier wave to obtain the drive signal g(t) of the switch. The value range of the node signal enhancement coefficient G is 0 < G < 0.1, and in this invention, G = 0.05.

[0013] The coefficient G can reduce the open-loop gain of the current inner loop in the control method, thus slowing down the response speed of the digital power communication power supply, which is reflected in a decrease in input impedance. The formula for calculating the open-loop gain is: K OL =G(K p +K i / s)G o (s), where K p K i These are the proportional and integral coefficients of the PI controller, respectively, G o(s) is the transfer function from power supply control to output in digital power communication.

[0014] The switches k1 and k2 enable the digital power communication power supply to operate in three node modes:

[0015] When k1 = 1 and k2 = 0, the communication reference current value i ref1 =s a (t), and without adding the node signal enhancement coefficient G, the digital power communication power supply operates in the transmitting node mode;

[0016] When k1 = 0 and k2 = 1, the communication reference current value i ref1 =0, and with the addition of the node signal enhancement coefficient G, the digital power communication power supply operates in receiver node mode;

[0017] When k1 = 0 and k2 = 0, the communication reference current value i ref1 =0, and no node signal enhancement factor G is added, so the digital power communication power supply operates in idle node mode.

[0018] This invention, without adding additional communication lines, uses a digital power communication power supply as the communication carrier. Through working node mode switching, nodes in an AC microgrid that need to send information operate in transmitting node mode; nodes that need to receive information operate in receiving node mode; and the remaining nodes operate in idle node mode. A node signal enhancement coefficient G is added to the receiving node control, making its input impedance relatively lower than other nodes. This allows the receiving node to receive more communication current, effectively solving the problem of weak and uniform communication current at each node in a multi-node AC microgrid, thus making communication more reliable.

[0019] The method of the present invention further includes a communication signal demodulation section, the communication signal demodulation section comprising:

[0020] Sampling receiver node digital power communication power supply input current i in The input current i in After passing through a 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 signal carrier msinω s Multiply by t and then by the input voltage v ac The symbolic function v sign Multiply, the result s b (t) is obtained after passing through a low-pass filter LPF. L (t);

[0022] For s L(t) is sampled and decided to obtain the binary output signal s(t); the sampling and decision process includes: detecting the positive and negative signs of the intermediate signal in each symbol, 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 recover the signal more accurately, enabling the receiving node to work effectively in low signal-to-noise ratio environments such as multi-node and long-distance environments.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. Compared with the auxiliary power supply of traditional inverters, the present invention not only provides auxiliary power supply for the inverter, but also adds resonant amplification inductor and resonant amplification capacitor, enabling the digital power communication power supply itself to have information transmission and reception capabilities.

[0026] 2. This invention effectively solves the communication limitation problem in multi-node, long-distance AC microgrids without adding extra communication lines. Increasing the node signal enhancement coefficient G allows more communication current to be received by the receiving node, making communication more reliable.

[0027] 3. This invention is embedded inside the inverter and is directly powered by a single-phase AC power grid, eliminating the need for additional power supply circuits and hardware demodulation circuits, thus reducing design costs. Attached Figure Description

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

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

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

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

[0032] Figure 5 A schematic diagram of four digital power communication power nodes in different node modes;

[0033] Figure 6 for Figure 5 A schematic diagram of the communication current waveform received by the digital power communication power supply in this scenario.

[0034] Figure 7 for Figure 5 A schematic diagram comparing the binary source code and the demodulated output waveform of the receiving node in the scenario. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort 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 supporting information in multi-node AC microgrids, such as... Figure 1 As shown, the multi-node AC microgrid in this embodiment includes a multi-node inverter; the inverter input is connected to multiple types of DC power supplies V. DC The output terminal 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 and includes: 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 D1, D2, D3, and D4. The anode of diode D1 and the cathode of diode D3 are connected to the AC input V. ac Terminal a of diode D2 is connected to the anode of diode D4, and the positive terminal of diode D2 is connected to the negative terminal of diode D4. This is the AC input V. ac The b-end; the AC input v ac It represents the voltage of any phase of the three-phase AC bus.

[0040] The LC resonant amplifier module includes a resonant amplification inductor L1, one end of which is connected to the output terminal c of the uncontrolled rectifier bridge, and the other end is connected to one end of the resonant amplification capacitor C1; the other end of the resonant amplification capacitor C1 is connected to the output terminal d of the uncontrolled rectifier bridge.

[0041] The single-stage Boost-Flyback module includes an inductor L2, one end of which is connected to the resonant amplification inductor L1, and the other end is connected to the positive terminals of diodes D5 and D6. The negative terminal of diode D5 is connected to the drain of the switching transistor S1 and the magnetizing inductor L. m One end of the switching transistor is connected to the output terminal d of the uncontrolled rectifier bridge module and one end of capacitor C2. The other end of capacitor C2 is connected to the negative terminal of diode D6 and the magnetizing inductor L. m The other end is connected; magnetizing inductor L mIt is connected in parallel with the primary winding of the high-frequency transformer; the same-name terminal of the secondary winding of the high-frequency transformer is connected to one side of capacitor C3, the other side of capacitor C3 is connected to the negative terminal of diode D7, and the positive terminal of diode D7 is connected to the other end of the complex winding of the high-frequency transformer.

[0042] Digital power communication power supplies can change the on / off process of switching transistor S1 through integrated power information control, so as to provide auxiliary power supply to the inverter while transmitting communication signals through the input power line.

[0043] Example 2

[0044] like Figure 3 As shown, this embodiment proposes an integrated power information control method to change the on / off process of the switching transistor S1, so as to realize that the digital power communication power supply can both provide auxiliary power supply to the inverter and transmit communication signals through the power line.

[0045] A power information integrated control method alters the on / off process of switch S1, the specific steps of which include:

[0046] 1) Reference output voltage v out_ref The output voltage v obtained across the sampling capacitor C3 out The output voltage error value is obtained by subtraction, and after passing through the PI controller, it is compared with the AC input voltage. ac The absolute value of the synchronous sinusoidal signal |sinω i Multiplying t| gives the power reference current value i ref2 In the formula ω i This is the angular frequency of the power grid.

[0047] 2) The binary baseband data signal a(t) is multiplied by 2 and then subtracted by 1, and then multiplied by the sinusoidal carrier signal to obtain the modulation signal carrier s. a (t)=(2a(t)-1)msinω s t, and then obtain the communication reference current value i through switch k1. ref1 In the formula, m is the amplitude of the signal carrier, and ω s This is the signal carrier frequency.

[0048] 3)i ref1 and i ref2 The reference current value i is obtained by adding them together. ref The reference current value i ref The absolute value of the sampled input current |i in The difference is processed by a PI controller to obtain the first result; the node signal enhancement coefficient G is passed through switch k2 and multiplied by the first result to obtain the duty cycle signal d; the duty cycle signal d is compared with the triangular carrier wave to obtain the drive signal g(t) of the switch S1;

[0049] To facilitate the switching of node modes for the digital power communication power supply, this embodiment provides the switching methods for control switches k1 and k2, enabling the digital power communication power supply to operate in three node modes:

[0050] When k1 = 1 and k2 = 0, the communication reference current value i ref1 =s a (t), and without adding the node signal enhancement coefficient G, the digital power communication power supply operates in the transmitting 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 at the same time provides auxiliary power supply to the inside of the inverter.

[0051] When k1 = 0 and k2 = 1, the communication reference current value i ref1 =0, and with the addition of the node signal enhancement factor G, the digital power communication power supply operates 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, making it easy to receive communication signals, and at the same time providing auxiliary power supply to the inverter.

[0052] When k1 = 0 and k2 = 0, the communication reference current value i ref1 =0, and no node signal enhancement factor G is added. The digital power communication power supply operates in idle node mode. At this time, the communication current intensity in the input current of the digital power communication power supply is weak, making it difficult to receive communication signals. At the same time, it provides auxiliary power supply 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 information support in multi-node AC microgrids. The specific steps are as follows:

[0054] 1) Input current i of digital power communication power supply at the sampling receiving node in The input current i in After passing through a 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 signal carrier msinω s Multiply by t and then by the input voltage v ac The symbolic function v sign Multiply, the result s b (t) is obtained after passing through a low-pass filter LPF. L (t).

[0056] 3) For s L The sampling decision is performed to obtain the binary output signal s(t). The sampling decision is made by detecting the sign of the intermediate signal in each symbol. When it is greater than 0, the output is 1, and when it is less than 0, the output is 0.

[0057] like Figure 5 As shown, this embodiment uses a digital power communication power supply suitable for supporting information in a multi-node AC microgrid to form a 4-node communication network. By giving control switches k1 and k2, digital power communication power supply #1 operates as the transmitting node, digital power communication power supply #2 operates as the receiving node, and digital power communication power supply #3 and digital power communication power supply #4 operate as idle nodes.

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

[0059] like Figure 7 As shown, in this embodiment... Figure 5 The 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. Furthermore, the communication method has a low bit error rate and strong communication reliability.

[0060] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0061] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A control method for a digital power communication power supply suitable for information support in multi-node AC microgrids, the digital power communication power supply for information support in multi-node AC microgrids comprising an uncontrolled rectifier bridge module, an LC resonant amplifier module, and a single-stage Boost-Flyback module connected in sequence; the uncontrolled rectifier bridge module includes two parallel bridge arms, the input side of which is connected to any phase of a three-phase AC bus; the LC resonant amplifier module includes a resonant amplifying inductor connected to one output terminal of the uncontrolled rectifier bridge module, the resonant amplifying inductor being connected to one end of a resonant amplifying capacitor, and the other end of the resonant amplifying capacitor being connected to the uncontrolled rectifier bridge module. The other output terminal of the 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 anode of two parallel diodes. The cathode of the first diode is connected to the drain of the switching transistor and one end of the magnetizing inductor. The source of the switching transistor is connected to the output of the uncontrolled rectifier bridge module and one end of the first capacitor. The other end of the first capacitor is connected to the cathode of the second diode and the other end of the magnetizing inductor. The magnetizing 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 third diode is connected to one end of the secondary winding of the high-frequency transformer. The feature is that... Includes the following steps: Reference output voltage value With the second capacitor Output voltage obtained from both ends The output voltage error value is obtained by subtraction, and then compared with the input voltage by the PI controller. absolute value of synchronous sinusoidal signal Multiply by this to obtain the power reference current value. In the formula The angular frequency of the power grid; Using binary baseband data signals Obtain the modulated signal carrier Then through the switch Obtain the communication reference current value In the formula, m is the amplitude of the signal carrier. The angular frequency of the signal carrier. Power reference current value and communication reference current value The reference current value is obtained by adding them together. The reference current value The absolute value of the sampled input current The difference is calculated, and the difference is processed by a PI controller to obtain the first result; the node signal enhancement coefficient G is obtained through a switch. Multiplying this by the first result yields the duty cycle signal d; comparing this duty cycle signal d with the triangular carrier wave yields the drive signal for the switching transistor. .

2. The method according to claim 1, characterized in that, 。 3. The method according to claim 1 or 2, characterized in that, 。 4. The method according to claim 1, characterized in that, The switch and Enables the digital power communication power supply to operate in three node modes: when =1, When =0, the communication reference current value Furthermore, without the addition of the node signal enhancement factor G, the digital power communication power supply operates in the transmitting node mode; when =0, When =1, the communication reference current value Furthermore, with the addition of a node signal enhancement factor G, the digital power communication power supply operates in receiver node mode; when =0, When =0, the communication reference current value Furthermore, without the addition of the node signal enhancement factor G, the digital power communication power supply operates in idle node mode.

5. The method according to claim 1, characterized in that, It also includes a communication signal demodulation section, which includes: Sampling receiver node digital power communication power supply input current The input current After passing through a bandpass filter (BPF), a communication current component with the same frequency as the signal carrier is obtained. ; The communication current component With signal carrier Multiply and then add to the input voltage sign function Multiply, the result After passing through a low-pass filter (LPF), the result is obtained. ; right Sampling and decision-making are performed to obtain the binary output signal. The sampling decision process includes: detecting the sign of the intermediate signal within each symbol; when it is greater than 0... The value is 1 when it is less than 0. It is 0.

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