Power line carrier communication method and device for mine emergency microgrid

Abstract

The present disclosure proposes a power line carrier communication method and device for a mine emergency microgrid, which is applied to a mine emergency microgrid. The mine emergency microgrid includes: a battery and a plurality of distributed generators, the battery and the distributed generator are respectively connected to a common AC bus based on an inverter, and the battery is located upstream of the current of the distributed generator. The method includes: the inverter corresponding to the target generator parses the upstream PLC signal from the upstream current; according to the upstream PLC signal, the unit load information of the upstream generator is determined, wherein the unit load information of the upstream generator is used to instruct the target generator to adjust the power; the inverter corresponding to the target generator removes the upstream PLC signal in the common AC bus, and injects a new PLC signal into the downstream current according to the unit load information of the target generator. Thus, the communication system constructed based on PLC can realize the dynamic redistribution of the output power of the generator, thereby ensuring the power supply safety of the emergency microgrid.

Description

Technical Field

[0001] The present disclosure relates to the technical field of mine power supply safety, and in particular to a power line carrier communication method and device for a mine emergency microgrid. Background Art

[0002] The emergency microgrid in coal mines can provide power to key equipment (hoists, ventilators, drainage pumps, etc.) in the event of power shortage or power outage in the main grid, thereby ensuring the normal operation of key equipment. The emergency microgrid consists of distributed generators (DG) and battery storage systems (BSS), which can be built on the existing power distribution infrastructure and have the advantages of simple structure, high stability and good power quality.

[0003] For emergency microgrids, if one or more DGs fail or have insufficient output power, how to ensure reliable power supply to the load is an important issue for emergency microgrids. Summary of the invention

[0004] The present disclosure aims to solve one of the technical problems in the related art at least to some extent.

[0005] To this end, the purpose of the present invention is to propose a power line carrier communication method, device, computer equipment and storage medium for mine emergency microgrid, which can realize dynamic redistribution of generator output power based on the communication system constructed by PLC, thereby ensuring the power supply safety of the emergency microgrid.

[0006] To achieve the above-mentioned object, a power line carrier communication method for a mine emergency microgrid proposed in an embodiment of the first aspect of the present disclosure is applied to a mine emergency microgrid, wherein the mine emergency microgrid comprises: a battery and a plurality of distributed generators, wherein the battery and the distributed generators are respectively connected to a common AC bus based on an inverter, and the battery is located upstream of the current of the distributed generators, and the method comprises:

[0007] The inverter corresponding to the target generator parses the upstream current to obtain the upstream PLC signal;

[0008] Determining unit load information of an upstream generator according to the upstream PLC signal, wherein the upstream generator and the target generator belong to the plurality of distributed generators, the upstream generator is located upstream of the current of the target generator and the two are adjacent, and the unit load information of the upstream generator is used to instruct the target generator to perform power adjustment;

[0009] The inverter corresponding to the target generator removes the upstream PLC signal in the common AC bus, and injects a new PLC signal into the downstream current according to the unit load information of the target generator.

[0010] To achieve the above-mentioned object, a power line carrier communication device for a mine emergency microgrid proposed in an embodiment of the second aspect of the present disclosure is applied to a mine emergency microgrid, wherein the mine emergency microgrid comprises: a battery and a plurality of distributed generators, wherein the battery and the distributed generators are respectively connected to a common AC bus based on an inverter, and the battery is located upstream of the current of the distributed generators, and the device comprises:

[0011] The analysis module is used to control the inverter corresponding to the target generator to analyze the upstream PLC signal from the upstream current;

[0012] a determination module, configured to determine unit load information of an upstream generator according to the upstream PLC signal, wherein the upstream generator and the target generator belong to the plurality of distributed generators, the upstream generator is located upstream of the current of the target generator and the two are adjacent, and the unit load information of the upstream generator is used to instruct the target generator to perform power adjustment;

[0013] A signal processing module is used to control the inverter corresponding to the target generator to remove the upstream PLC signal in the common AC bus, and inject a new PLC signal into the downstream current according to the unit load information of the target generator.

[0014] The computer device proposed in the third aspect embodiment of the present disclosure includes: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the power line carrier communication method for a mine emergency microgrid proposed in the first aspect embodiment of the present disclosure is implemented.

[0015] The fourth aspect embodiment of the present disclosure proposes a non-temporary computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, it implements the power line carrier communication method for a mine emergency microgrid as proposed in the first aspect embodiment of the present disclosure.

[0016] The fifth aspect of the present disclosure provides a computer program product. When the instructions in the computer program product are executed by a processor, the power line carrier communication method for a mine emergency microgrid as provided in the first aspect of the present disclosure is performed.

[0017] The power line carrier communication method, device, computer equipment and storage medium for mine emergency microgrid provided by the present disclosure are applied to mine emergency microgrid, which includes: a battery and multiple distributed generators, the battery and the distributed generator are respectively connected to a common AC bus based on an inverter, and the battery is located upstream of the current of the distributed generator. The method includes: the inverter corresponding to the target generator parses the upstream PLC signal from the upstream current; according to the upstream PLC signal, the unit load information of the upstream generator is determined, wherein the upstream generator and the target generator belong to multiple distributed generators, the upstream generator is located upstream of the current of the target generator and the two are adjacent, and the unit load information of the upstream generator is used to instruct the target generator to adjust the power; the inverter corresponding to the target generator removes the upstream PLC signal in the common AC bus, and injects a new PLC signal into the downstream current according to the unit load information of the target generator. Thus, the communication system constructed based on PLC can realize the dynamic redistribution of the output power of the generator, thereby ensuring the power supply safety of the emergency microgrid.

[0018] Additional aspects and advantages of the present disclosure will be given in part in the following description and in part will be obvious from the following description or learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present disclosure will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0020] Figure 1 It is a flow chart of a power line carrier communication method for a mine emergency microgrid proposed in an embodiment of the present disclosure;

[0021] Figure 2 is a flow chart of a power line carrier communication method for a mine emergency microgrid proposed in another embodiment of the present disclosure;

[0022] Figure 3 is a schematic diagram of the structure of a distributed microgrid proposed in the present disclosure;

[0023] Figure 4 is a single DG current control diagram proposed according to the present disclosure;

[0024] Figure 5 is a structural schematic diagram of a load balancing integrator proposed in the present disclosure;

[0025] Figure 6a According to the DG proposed in this disclosure 1 Schematic diagram of the change of D-axis current when the PLC signal is injected;

[0026] Figure 6b According to the DG proposed in this disclosure1 Schematic diagram of the change of phase A current when the PLC signal is injected;

[0027] Figure 7a is a schematic diagram of the change of the D-axis current when the BSS proposed in the present disclosure blocks the PLC signal;

[0028] Figure 7b is a schematic diagram of the change of the A phase current when the BSS proposed in the present disclosure blocks the PLC signal;

[0029] Figure 8 is a schematic diagram of the structure of high-frequency signal feedback compensation proposed in the present disclosure;

[0030] Fig. 9 is a Bode plot of feedback gain proposed according to the present disclosure;

[0031] Fig.10 is a DG current control diagram including PLC suppression proposed in accordance with the present disclosure;

[0032] Fig.11a is a schematic diagram of the change of the D-axis current when the PLC signal is suppressed according to the present disclosure;

[0033] Fig.11b is a schematic diagram of the change of the A-phase current when the PLC signal is suppressed according to the present disclosure;

[0034] Fig.12 is a schematic diagram of a PLC suppression loop response curve proposed in the present disclosure;

[0035] Fig.13 It is a structural schematic diagram of a power line carrier communication device for a mine emergency microgrid proposed in an embodiment of the present disclosure;

[0036] Fig.14 A block diagram of an exemplary computer device suitable for implementing embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0037] Embodiments of the present disclosure are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present disclosure, and are not to be construed as limitations of the present disclosure. On the contrary, the embodiments of the present disclosure include all changes, modifications, and equivalents that fall within the spirit and connotation of the appended claims.

[0038] Figure 1 It is a flow chart of a power line carrier communication method for a mine emergency microgrid proposed in an embodiment of the present disclosure.

[0039] Among them, it should be noted that the executor of the power line carrier communication method for mine emergency microgrid in this embodiment is the mine emergency microgrid, and the mine emergency microgrid includes: batteries and multiple distributed generators, the batteries and distributed generators are respectively connected to the common AC bus based on inverters, and the batteries are located upstream of the distributed generators.

[0040] like Figure 1 As shown, the power line carrier communication method for a mine emergency microgrid includes:

[0041] S101: The inverter corresponding to the target generator parses the upstream current to obtain an upstream PLC signal.

[0042] The target generator may refer to any one of the multiple distributed generators of the mine emergency microgrid that has a corresponding upstream generator. That is, in the embodiment of the present disclosure, the target generator may refer to any one of the multiple distributed generators that is not adjacent to the battery.

[0043] The upstream circuit refers to the current flowing from the common AC bus into the inverter corresponding to the target generator.

[0044] Among them, PLC (Power Line Communication) signals refer to signals that are transmitted through power lines. In PLC systems, power lines are not only used to transmit electrical energy, but also as a medium for data transmission. PLC signals can be transmitted in the range of low frequency (tens of kHz) to high frequency (hundreds of MHz). Upstream PLC signals refer to PLC signals sent by upstream generators to target generators.

[0045] It is understandable that when a distributed generator (DG) in a mine emergency microgrid fails or has reduced power, the battery (Battery Energy Storage System, BSS) will perform power compensation. However, the energy provided by the battery is limited. In order to ensure the normal operation of the power system, other normal distributed generators need to be reallocated. In the embodiment of the present disclosure, when the upstream PLC signal is obtained by parsing the upstream current by the inverter corresponding to the target generator, reliable data support can be provided for the subsequent determination of the unit load information of the upstream generator.

[0046] S102: Determine the unit load information of the upstream generator according to the upstream PLC signal, wherein the upstream generator and the target generator belong to a plurality of distributed generators, the upstream generator is located upstream of the current of the target generator and the two are adjacent, and the unit load information of the upstream generator is used to instruct the target generator to adjust power.

[0047] The unit load information is used to indicate the ratio of the actual output power of the upstream generator to the rated output power.

[0048] In the disclosed embodiment, after determining the unit load information of the upstream generator, the target generator can determine the real-time output power of the upstream generator based on the unit load information, and compare the real-time output power with the power output upper limit of the upstream generator; if the real-time output power of the upstream generator has reached the corresponding power output upper limit, the target generator increases its own power output.

[0049] In the disclosed embodiment, after the unit load information of the upstream generator is determined according to the upstream PLC signal, the target generator can be accurately and quickly instructed to adjust the power based on the unit load information, thereby realizing dynamic redistribution of the DG output power.

[0050] S103: The inverter corresponding to the target generator removes the upstream PLC signal in the common AC bus, and injects a new PLC signal into the downstream current according to the unit load information of the target generator.

[0051] That is, after receiving the upstream PLC signal, the target generator in the embodiment of the present disclosure can remove the upstream PLC signal from its downstream current to avoid the upstream PLC signal from affecting the generator downstream of the target generator.

[0052] The new PLC signal may be transmitted to the adjacent downstream generator corresponding to the target generator, thereby indicating the power adjustment process of the corresponding downstream generator.

[0053] In this embodiment, the upstream PLC signal is obtained by parsing the upstream current by the inverter corresponding to the target generator; the unit load information of the upstream generator is determined according to the upstream PLC signal, wherein the upstream generator and the target generator belong to multiple distributed generators, the upstream generator is located upstream of the current of the target generator and the two are adjacent, and the unit load information of the upstream generator is used to instruct the target generator to adjust the power; the inverter corresponding to the target generator removes the upstream PLC signal in the common AC bus, and injects a new PLC signal into the downstream current according to the unit load information of the target generator, thereby enabling the communication system constructed based on PLC to realize dynamic redistribution of the generator output power, thereby ensuring the power supply safety of the emergency microgrid.

[0054] The present disclosure also proposes a power line carrier communication method for a mine emergency microgrid, wherein an upstream PLC signal and a new PLC signal have the same preset frequency and preset amplitude.

[0055] The preset frequency and the preset amplitude may refer to the signal frequency and amplitude configured for the PLC communication process in the embodiment of the present disclosure. The preset frequency may be, for example, 800 Hz, or may be any other frequency, without limitation. The preset amplitude corresponding value should satisfy the requirement that the PLC signal is visible in the time domain diagram.

[0056] That is, the PLC signal used in the power line carrier communication process of the present disclosure has the same preset frequency and preset amplitude, so as to facilitate the generation, analysis and removal of the PLC signal, reduce harmonic pollution and improve communication quality.

[0057] The present disclosure also proposes a power line carrier communication method for a mine emergency microgrid, wherein the voltage control bandwidth of the battery corresponding inverter is higher than the voltage control bandwidth of the distributed generator corresponding inverter, and a notch filter is configured at the battery corresponding inverter based on a preset frequency.

[0058] In the embodiment of the present disclosure, when the voltage control bandwidth of the inverter corresponding to the battery is higher than the voltage control bandwidth of the inverter corresponding to the distributed generator, then when a system failure occurs, the inverter corresponding to the battery can respond more quickly to changes in the power grid or load, thereby having higher flexibility and reliability in the power system.

[0059] It can be understood that when power line carrier communication is performed based on PLC signals in the embodiments of the present disclosure, the current in the common AC bus may change, thereby causing the battery corresponding inverter to suppress the PLC signal to maintain a constant AC bus voltage and frequency. In the embodiments of the present disclosure, by configuring a notch filter based on a preset frequency at the battery corresponding inverter, the BSS current and voltage measurement can be made invisible to the injected PLC signal, thereby effectively improving the reliability of the power line carrier communication process.

[0060] Figure 2 It is a flow chart of a power line carrier communication method for a mine emergency microgrid proposed in another embodiment of the present disclosure.

[0061] like Figure 2 As shown, the power line carrier communication method for a mine emergency microgrid includes:

[0062] S201: configuring a narrow bandpass filter at the inverter corresponding to the target generator with a preset frequency as the center frequency to filter the upstream current to obtain an initial PLC signal.

[0063] Among them, a narrowband pass filter is a filter that selects signals within a specific frequency range and blocks signals in other frequency ranges. It has a narrow passband width and only allows signals within a certain frequency range to pass.

[0064] In the disclosed embodiment, when a narrow bandpass filter with a preset frequency as the center frequency is configured at the inverter corresponding to the target generator, a PLC signal can be quickly and accurately extracted from the upstream current.

[0065] S202: Determine an amplitude threshold based on a preset amplitude.

[0066] The amplitude threshold may refer to a threshold determined based on a preset amplitude.

[0067] In the embodiment of the present disclosure, when the amplitude threshold is determined based on the preset amplitude, reliable reference information can be provided for subsequent filtering processing of the initial PLC signal.

[0068] S203: Filter the initial PLC signal according to the amplitude threshold to obtain an upstream PLC signal.

[0069] For example, in the embodiment of the present disclosure, a signal whose amplitude exceeds a threshold value may be regarded as a valid signal, otherwise it may be regarded as an interference signal.

[0070] It is understandable that there may be interference signals in the initial PLC signal. When the initial PLC signal is filtered according to the amplitude threshold, the reliability of the obtained upstream PLC signal can be effectively improved.

[0071] That is to say, in the embodiments of the present disclosure, a narrow bandpass filter can be configured at the inverter corresponding to the target generator with a preset frequency as the center frequency to obtain an initial PLC signal after filtering the upstream current, and the amplitude threshold is determined based on the preset amplitude. The initial PLC signal is filtered according to the amplitude threshold to obtain an upstream PLC signal, thereby effectively improving the reliability and practicality of the obtained upstream PLC signal.

[0072] S204: Determine the unit load information of the upstream generator according to the upstream PLC signal, wherein the upstream generator and the target generator belong to a plurality of distributed generators, the upstream generator is located upstream of the current of the target generator and the two are adjacent, and the unit load information of the upstream generator is used to instruct the target generator to adjust power.

[0073] The description of S204 can be specifically referred to the above embodiment, which will not be repeated here.

[0074] S205: Suppressing the upstream PLC signal based on a preset feedback loop, wherein the preset feedback loop is between an output point of an inverter corresponding to the target generator and an injection point of the new PLC signal.

[0075] That is to say, in the embodiment of the present disclosure, the upstream PLC signal can be suppressed based on a preset feedback loop, wherein the preset feedback loop is between the output point of the inverter corresponding to the target generator and the injection point of the new PLC signal. Thus, the suppression effect of the upstream PLC signal can be effectively improved based on the feedback loop.

[0076] S206: Determine relative position information of the target generator among the multiple distributed generators.

[0077] The relative position information may be used to indicate the relative position of the target generator in the upstream and downstream of the current.

[0078] In the disclosed embodiment, after the relative position information of the target generator among the multiple distributed generators is determined, a reliable triggering basis can be provided for subsequently injecting a new PLC signal into the downstream current according to the unit load information of the target generator.

[0079] S207: If the relative position information indicates that there is a corresponding downstream generator downstream of the current of the target generator, a new PLC signal is injected into the downstream current according to the unit load information of the target generator, wherein the downstream generator belongs to multiple distributed generators and is adjacent to the target generator, and the unit load information of the target generator is used to instruct the downstream generator to adjust power.

[0080] That is to say, in the embodiment of the present disclosure, the relative position information of the target generator among the multiple distributed generators can be determined. If the relative position information indicates that there is a corresponding downstream generator downstream of the current of the target generator, a new PLC signal is injected into the downstream current according to the unit load information of the target generator, wherein the downstream generator belongs to multiple distributed generators and is adjacent to the target generator, and the unit load information of the target generator is used to instruct the downstream generator to adjust power. Therefore, a reliable triggering basis can be provided for injecting the new PLC signal, thereby effectively avoiding the influence of the PLC signal on the load operation process.

[0081] In this embodiment, a narrow bandpass filter is configured at the inverter corresponding to the target generator with a preset frequency as the center frequency to obtain an initial PLC signal after filtering the upstream current, and an amplitude threshold is determined based on a preset amplitude. The initial PLC signal is filtered according to the amplitude threshold to obtain an upstream PLC signal, thereby effectively improving the reliability and practicality of the obtained upstream PLC signal. The upstream PLC signal is suppressed based on a preset feedback loop, wherein the preset feedback loop is between the output point of the inverter corresponding to the target generator and the injection point of the new PLC signal, thereby effectively improving the suppression effect of the upstream PLC signal based on the feedback loop. The relative position information of the target generator among the multiple distributed generators is determined, and if the relative position information indicates that there is a corresponding downstream generator downstream of the current of the target generator, a new PLC signal is injected into the downstream current according to the unit load information of the target generator, wherein the downstream generator belongs to multiple distributed generators and is adjacent to the target generator, and the unit load information of the target generator is used to instruct the downstream generator to adjust the power, thereby providing a reliable trigger basis for injecting the new PLC signal, effectively avoiding the influence of the PLC signal on the load operation process.

[0082] For example, Figure 3 As shown, Figure 3 : is a schematic diagram of the structure of a distributed microgrid proposed in the present disclosure, wherein all DGs and BSSs are connected to a common AC bus through an inverter, and all loads are connected at a common point v L Except for battery charging (not considered here), all DG currents are unidirectional: from left to right. It should be noted that from the perspective of PLC implementation, it is more convenient for DG inverters to measure upstream currents than downstream currents. In this way, the PLC signal can be transmitted by the upstream DG n received and then removed downstream. Figure 4 is a single DG current control diagram proposed in the present disclosure, noting that i n =i n+1 +i Sn Leading to Figure 4 The current control diagram shown in the figure is n+1 The upstream current drive.

[0083] If the proportion of inverter n output power in the total load is given by E n Given, then E n and D n The contrast relationship between them can be seen from the following formula

[0084]

[0085] Where S n ——DG nConfiguration power.

[0086] Two identical DGs provide the same proportion of power to the load: E 1 =E 2 =0.5, D 1 =0.5, D 2 =1, when a load step change occurs, the two DGs change synchronously to a new current level. At this time, the BSS provides a transient high current to supplement the shortage of the grid. 1 If a fault occurs, DG 2 will automatically attempt to supply full load current because D 2 = 1. If its output is saturated, then the BSS will automatically provide the remainder of the load current. However, if DG 2 If a failure occurs, then DG 1 will not notice this fault and will continue to supply only half the load current because D 1 = 0.5. The remaining half of the load current will be provided by the BSS, which will result in an unnecessarily high battery discharge rate.

[0087] To address this problem, the present disclosure proposes a method for adjusting DG output power through PLC communication, whereby when one of the DGs fails or its power is reduced, the output power of other DGs is automatically adjusted to meet the load power demand.

[0088] Due to the narrow space in coal mines, the application of frequency converters and large-scale mining equipment has caused serious harmonic interference in the underground power grid. The amplitude of PLC signals is easily affected by harmonic interference, causing signal distortion, but the communication frequency is not greatly affected. Therefore, the PLC communication is designed to use a fixed frequency method to reduce harmonic pollution and improve communication quality.

[0089] The designed PLC uses high frequency (HF) signals for communication, which are transmitted through the same medium (power line) as the power supply current. This paper proposes a communication control strategy for adjacent PLCs at the same frequency. The communication logic is that the upstream inverter DG n+1 Notify downstream neighbor DG n Its unit load information, the unit load information expression is

[0090]

[0091] Where P n+1 ——DG n+1 The actual output power;

[0092] P Max,n+1 ——DG n+1 The maximum output power is the rated output power.

[0093] Information is transmitted in the form of a PLC signal for a given duration and then repeated periodically. s In the example, the duty cycle of the PLC signal is used to represent the unit load information L n+1 The downstream inverter receives this signal, calculates the load information of the upstream DG, removes it from the current, and injects its own PLC signal for the next downstream DG to receive.

[0094] like Figure 5 As shown, Figure 5 is a schematic diagram of the structure of the load balancing integrator proposed in the present disclosure, wherein the unit load L n+1 The information can be used in the following ways: Inverter DG n pass Figure 5 The integral loop shown realizes its own load L n The phase balance with its neighbors, the upstream neighbors and its own load difference drive the integrator to achieve D n changes.

[0095] The PLC communication signal processing process includes three aspects: PLC injection, PLC detection and PLC suppression.

[0096] (1)PLC signal injection

[0097] The PLC signal is injected through the inverter DG n Output voltage The frequency added is ω PLC The harmonic signal is realized by the downstream inverter DG n-1 This current component will be detected. Figure 4 As shown, the injected signal is represented by a n , then:

[0098]

[0099] Where A is the voltage amplitude of PLC signal;

[0100] ——Reference voltage for inverter current control (without PLC).

[0101] PLC injection Figure 6a , 6b As shown, Figure 6a According to the DG proposed in this disclosure 1 Schematic diagram of the change of D-axis current when the PLC signal is injected. Figure 6b According to the DG proposed in this disclosure 1Schematic diagram of the change of phase A current when the PLC signal is injected, where the PLC frequency is 800 Hz and the amplitude A of the PLC is set high enough to be visible in the time domain diagram.

[0102] In the microgrid, the BSS inverter plays a role in voltage control, so that the voltage of the DG inverter connected to the AC bus has a constant amplitude and frequency. To this end, the BSS inverter voltage control is designed to have a higher bandwidth than the DG inverter current control.

[0103] In the PLC injection scenario, the BSS inverter will respond to the PLC injection with the goal of maintaining a constant AC bus voltage and frequency. In the process, it will generate harmonic currents of the same magnitude and opposite phase to the PLC current, such as Figure 6a and Figure 6b As shown. Due to the compensation effect of BSS inverter, the DG 2 The PLC signal did not achieve the expected effect.

[0104] To prevent this from happening, digital notch filters are added to the BSS current and voltage measurements to make them invisible to the injected PLC signals. The effect of using notch filters in BSS measurements is shown below: Figure 7a , 7b As shown, Figure 7a 7a is a schematic diagram of the change of the D-axis current when the BSS proposed in the present disclosure blocks the PLC signal, and 7b is a schematic diagram of the change of the A-phase current when the BSS proposed in the present disclosure blocks the PLC signal. 2 The PLC signal sent can reach DG 1 ,DG 1 will be able to detect it and extract useful information.

[0105] (2)PLC signal detection

[0106] The PLC signal is transmitted from the upstream DG to the downstream neighbor. Since the frequency is fixed, the downstream DG will be able to detect the signal more easily. PLC The narrow bandpass filter with the center frequency is used to detect the signal, and the amplitude of the signal is compared with the threshold to filter the interference signal.

[0107] (3) PLC signal suppression

[0108] All DGs in a microgrid use the same PLC frequency, which reduces harmonic pollution in the microgrid and makes it easier to filter the PLC signal at the load end. However, this also brings challenges to the implementation of PLC. Each DG inverter needs to effectively remove the detected PLC signal from the current in order to re-inject its own PLC signal at the same frequency.

[0109] 1) Feedforward scheme: The feedforward scheme for PLC signal suppression is as follows Figure 4 As shown, the injection frequency ω PLC The signal makes DG n Inverter output current Received from upstream The PLC signal is completely opposite. Then, in the downstream current, due to The upstream PLC signal will be completely suppressed.

[0110] Depend on Figure 4 The closed-loop control diagram of DG n The expression of the inverter output current is:

[0111]

[0112] Where a n ——L n / K n ;

[0113] β n ——L n / R n ;

[0114] s——R n / L n , R n is the output resistance of inverter n.

[0115] In order to compensate for the upstream current i n+1 , then

[0116]

[0117] From this we can determine that the required signal is

[0118]

[0119] According to formula (6), the PLC signal can be suppressed, but its effect on system parameter a n , β n and R n , The estimated quality of the magnitude, and It relies too much on the accuracy of the precise phase matching of the compensation current, which greatly reduces its application effect.

[0120] 2) Feedback scheme: In view of the above limitations of the feedforward scheme, a feedback scheme for PLC signal suppression is proposed. Figure 8 As shown, Figure 8 is a schematic diagram of the structure of the high-frequency signal feedback compensation proposed in the present disclosure, in DG n Inverter output and injection point an Increase the gain K h feedback loop.

[0121] from Figure 8 It can be concluded that

[0122]

[0123] If the feedback current is relatively large, then:

[0124]

[0125] In the formula

[0126] i n+1 with i Sn The Bode plot of the transfer function between Fig. 9 As shown, Fig. 9 is a Bode plot of the feedback gain proposed in the present disclosure. Since this transfer function also affects the main current control loop, it is important to ensure that it does not change the power frequency (50 Hz) current. Fig. 9 It can be seen that at low frequencies, the transfer function (8) can be simply expressed as D n , higher than 1 / β n The PLC frequency signal is suppressed.

[0127] DG current control diagram including PLC suppression, such as Fig.10 As shown, Fig.10 is a DG current control diagram including PLC suppression proposed in the present disclosure. Fig.10 The F block in the figure indicates the frequency ω PLC The simulation results of PLC signal suppression are shown in Fig.11a , 11b As shown, Fig.11a is a schematic diagram of the change of the D-axis current when the PLC signal is suppressed according to the present disclosure, Fig.11b is a schematic diagram of the change of phase A current when the PLC signal is suppressed according to the present disclosure. Fig.12 As shown, Fig.12 is a schematic diagram of the response curve of the PLC suppression loop proposed in the present disclosure, which shows the output of the PLC suppression loop. In the figure, DG 2 The time intervals for injecting PLC are: 0.02s~0.06s, 0.08s~0.10s, 0.12s~0.14s. After detecting the PLC signal, DG 1 successfully removed from the downstream current. Fig.12 As shown, the time constant of the cancellation loop is about 6ms.

[0128] Based on the power line carrier communication method for mine emergency microgrid proposed in the present disclosure, the load current can be shared by the power grid DG, and the dynamic redistribution of the DG output power can be achieved, thereby ensuring the power supply safety of the emergency microgrid. By coupling the communication signal to the power line for communication and using the power line as the communication channel, the laying of communication lines in the microgrid can be greatly reduced, which not only reduces the engineering workload, but also can meet the communication needs of the microgrid.

[0129] Fig.13 It is a structural schematic diagram of a power line carrier communication device for a mine emergency microgrid proposed in an embodiment of the present disclosure.

[0130] like Fig.13 As shown, the power line carrier communication device 130 for a mine emergency microgrid is applied to a mine emergency microgrid, which includes: a battery and a plurality of distributed generators, the battery and the distributed generators are respectively connected to a common AC bus based on an inverter, the battery is located upstream of the current of the distributed generator, and the device includes:

[0131] The analysis module 1301 is used to control the inverter corresponding to the target generator to analyze the upstream current to obtain the upstream PLC signal;

[0132] A determination module 1302 is used to determine unit load information of an upstream generator according to an upstream PLC signal, wherein the upstream generator and the target generator belong to a plurality of distributed generators, the upstream generator is located upstream of the current of the target generator and the two are adjacent, and the unit load information of the upstream generator is used to instruct the target generator to perform power adjustment;

[0133] The signal processing module 1303 is used to control the inverter corresponding to the target generator to remove the upstream PLC signal in the common AC bus, and inject a new PLC signal into the downstream current according to the unit load information of the target generator.

[0134] It should be noted that the aforementioned explanation of the power line carrier communication method for a mine emergency microgrid is also applicable to the power line carrier communication device for a mine emergency microgrid of this embodiment, and will not be repeated here.

[0135] In this embodiment, the upstream PLC signal is obtained by parsing the upstream current by the inverter corresponding to the target generator; the unit load information of the upstream generator is determined according to the upstream PLC signal, wherein the upstream generator and the target generator belong to multiple distributed generators, the upstream generator is located upstream of the current of the target generator and the two are adjacent, and the unit load information of the upstream generator is used to instruct the target generator to adjust the power; the inverter corresponding to the target generator removes the upstream PLC signal in the common AC bus, and injects a new PLC signal into the downstream current according to the unit load information of the target generator, thereby enabling the communication system constructed based on PLC to realize dynamic redistribution of the generator output power, thereby ensuring the power supply safety of the emergency microgrid.

[0136] Fig.14 A block diagram of an exemplary computer device suitable for implementing embodiments of the present disclosure is shown. Fig.14 The computer device 12 shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present disclosure.

[0137] like Fig.14 As shown, the computer device 12 is in the form of a general-purpose computing device. The components of the computer device 12 may include, but are not limited to: one or more processors or processing units 16, a system memory 28, and a bus 18 that connects various system components (including the system memory 28 and the processing unit 16).

[0138] The bus 18 represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, a graphics acceleration port, a processor or a local bus using any of a variety of bus structures. For example, these architectures include but are not limited to Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MAC) bus, Enhanced ISA bus, Video Electronics Standards Association (VESA) local bus and Peripheral Component Interconnection (PCI) bus.

[0139] The computer device 12 typically includes a variety of computer system readable media. These media can be any available media that can be accessed by the computer device 12, including volatile and non-volatile media, removable and non-removable media.

[0140] The memory 28 may include computer system readable media in the form of volatile memory, such as random access memory (RAM) 30 and / or cache memory 32. The computer device 12 may further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, the storage system 34 may be used to read and write non-removable, non-volatile magnetic media ( Fig.14 Not shown, often called a "hard drive").

[0141] although Fig.14 Not shown in the figure, a disk drive for reading and writing a removable non-volatile disk (e.g., a "floppy disk"), and an optical disk drive for reading and writing a removable non-volatile optical disk (e.g., a compact disc read only memory (hereinafter referred to as: CD-ROM), a digital versatile disc read only memory (hereinafter referred to as: DVD-ROM) or other optical media) may be provided. In these cases, each drive may be connected to the bus 18 via one or more data medium interfaces. The memory 28 may include at least one program product having a set (e.g., at least one) of program modules that are configured to perform the functions of the various embodiments of the present disclosure.

[0142] A program / utility 40 having a set (at least one) of program modules 42 may be stored, for example, in the memory 28, such program modules 42 including but not limited to an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment. The program modules 42 generally perform the functions and / or methods of the embodiments described in the present disclosure.

[0143] The computer device 12 may also communicate with one or more external devices 14 (e.g., keyboard, pointing device, display 24, etc.), one or more devices that enable a human body to interact with the computer device 12, and / or any device that enables the computer device 12 to communicate with one or more other computing devices (e.g., network card, modem, etc.). Such communication may be performed via an input / output (I / O) interface 22. In addition, the computer device 12 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) via a network adapter 20. As shown, the network adapter 20 communicates with other modules of the computer device 12 via a bus 18. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the computer device 12, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0144] The processing unit 16 executes various functional applications and data processing by running the programs stored in the system memory 28, such as implementing the power line carrier communication method for the mine emergency microgrid mentioned in the above embodiment.

[0145] In order to implement the above embodiments, the present disclosure also proposes a non-temporary computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the power line carrier communication method for a mine emergency microgrid proposed in the above embodiments of the present disclosure is implemented.

[0146] In order to implement the above embodiments, the present disclosure further proposes a computer program product. When the instruction processor in the computer program product is executed, the power line carrier communication method for a mine emergency microgrid proposed in the above embodiments of the present disclosure is executed.

[0147] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. The present disclosure is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The description and examples are to be considered exemplary only, and the true scope and spirit of the present disclosure are indicated by the following claims.

[0148] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

[0149] It should be noted that, in the description of the present disclosure, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present disclosure, unless otherwise specified, the meaning of "plurality" is two or more.

[0150] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present disclosure includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present disclosure belong.

[0151] It should be understood that the various parts of the present disclosure can be implemented in hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0152] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0153] In addition, each functional unit in each embodiment of the present disclosure may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0154] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc.

[0155] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0156] Although the embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present disclosure. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present disclosure.

Claims

1. A power line carrier communication method for mine emergency microgrid, characterized in that: Applied to a mine emergency microgrid, the mine emergency microgrid comprises: a battery and a plurality of distributed generators, the battery and the distributed generators are respectively connected to a common AC bus based on an inverter, the battery is located upstream of the current of the distributed generators, and the method comprises: The inverter corresponding to the target generator parses the upstream current to obtain an upstream PLC signal, wherein the upstream current is the current flowing from the common AC bus into the inverter corresponding to the target generator; Determine the unit load information of the upstream generator according to the upstream PLC signal, wherein the upstream generator and the target generator belong to the multiple distributed generators, the upstream generator is located upstream of the current of the target generator and the two are adjacent, and the unit load information of the upstream generator is used to instruct the target generator to adjust the power; wherein the unit load information is used to indicate the ratio of the actual output power of the upstream generator to the rated output power; The inverter corresponding to the target generator removes the upstream PLC signal in the common AC bus, and injects a new PLC signal into the downstream current according to the unit load information of the target generator; The step of removing the upstream PLC signal from the common AC bus by the inverter corresponding to the target generator includes: Suppressing the upstream PLC signal based on a preset feedback loop, wherein the preset feedback loop is between an output point of an inverter corresponding to the target generator and an injection point of the new PLC signal; The injecting a new PLC signal into the downstream current according to the unit load information of the target generator comprises: Determining relative position information of the target generator among the multiple distributed generators; If the relative position information indicates that there is a corresponding downstream generator downstream of the current of the target generator, the new PLC signal is injected into the downstream current according to the unit load information of the target generator, wherein the downstream generator belongs to the multiple distributed generators and is adjacent to the target generator, and the unit load information of the target generator is used to instruct the downstream generator to adjust power.

2. The method according to claim 1, characterized in that The upstream PLC signal and the new PLC signal have the same preset frequency and preset amplitude.

3. The method according to claim 2, characterized in that The step of obtaining an upstream PLC signal by parsing the upstream current by the inverter corresponding to the target generator includes: configuring a narrow bandpass filter at the inverter corresponding to the target generator with the preset frequency as the center frequency to filter the upstream current to obtain an initial PLC signal; determining an amplitude threshold based on the preset amplitude; The initial PLC signal is filtered according to the amplitude threshold to obtain the upstream PLC signal.

4. The method according to claim 2, characterized in that The voltage control bandwidth of the inverter corresponding to the battery is higher than the voltage control bandwidth of the inverter corresponding to the distributed generator, and a notch filter is configured at the inverter corresponding to the battery based on the preset frequency.

5. A power line carrier communication device for a mine emergency microgrid, characterized in that: Applied to a mine emergency microgrid, the mine emergency microgrid comprises: a battery and a plurality of distributed generators, the battery and the distributed generators are respectively connected to a common AC bus based on an inverter, the battery is located upstream of the current of the distributed generators, and the device comprises: A parsing module, used for controlling the inverter corresponding to the target generator to parse the upstream current to obtain an upstream PLC signal, wherein the upstream current is the current flowing from the common AC bus into the inverter corresponding to the target generator; a determination module, configured to determine unit load information of an upstream generator according to the upstream PLC signal, wherein the upstream generator and the target generator belong to the plurality of distributed generators, the upstream generator is located upstream of the current of the target generator and the two are adjacent, and the unit load information of the upstream generator is used to instruct the target generator to perform power adjustment; wherein the unit load information is used to indicate a ratio of an actual output power of the upstream generator to a rated output power; A signal processing module, used for controlling the inverter corresponding to the target generator to remove the upstream PLC signal in the common AC bus, and injecting a new PLC signal into the downstream current according to the unit load information of the target generator; The signal processing module is further used to suppress the upstream PLC signal based on a preset feedback loop, wherein the preset feedback loop is between the output point of the inverter corresponding to the target generator and the injection point of the new PLC signal; The signal processing module is further used to determine the relative position information of the target generator among the multiple distributed generators; If the relative position information indicates that there is a corresponding downstream generator downstream of the current of the target generator, the new PLC signal is injected into the downstream current according to the unit load information of the target generator, wherein the downstream generator belongs to the multiple distributed generators and is adjacent to the target generator, and the unit load information of the target generator is used to instruct the downstream generator to adjust power.

6. A computer device, characterized in that: include: at least one processor; as well as a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 4.

7. A non-transitory computer-readable storage medium storing computer instructions, characterized in that: in, The computer instructions are used to cause the computer to execute the method according to any one of claims 1 to 4.

8. A computer program product, characterized in that The invention comprises a computer program which, when executed by a processor, implements the steps of the method according to any one of claims 1 to 4.

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