Parallel operation control method for maneuvering micro-grid and diesel power station

Abstract

The invention relates to a maneuvering micro-grid and diesel power station parallel operation control method, and belongs to the technical field of maneuvering micro-grids. The PCS in the maneuvering micro-grid samples alternating voltage and current on the load side, the active power given and the reactive power given of the PCS are deduced by calculating the active power, the reactive power and the slope of the load, the active power deviation and the reactive power deviation are calculated to adjust the power output of the PCS, and microsecond-level load balance adjustment of the maneuvering micro-grid and the diesel power station is achieved. The problems of slow load balance adjustment and poor non-linear load adaptability of parallel operation power supply of a maneuvering micro-grid and a diesel power station in a traditional mode are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of mobile microgrids, and in particular to a method for controlling parallel operation of a mobile microgrid and a diesel power station. Background Art

[0002] With the rapid development and cost reduction of new energy technologies such as photovoltaic, wind power generation, and energy storage batteries, microgrids constructed by combining wind power generation, photovoltaic power generation, traditional diesel generators, and traditional power grids have been widely used. Mobile microgrids developed for special application needs. Mobile microgrids are mobile and can be transferred by carrying people or on vehicles to meet mobile power supply needs.

[0003] The mobile microgrid is connected in parallel with the diesel engine for power supply. The common method is that the diesel engine is used as a voltage source and the mobile microgrid is used as a current source for power supply. The EMS inside the mobile microgrid controls the PCS power output according to the load change. Since the EMS needs to perform the acquisition, communication and control process, the entire process is calculated in seconds, so the response speed of the mobile microgrid is in seconds, and it is impossible to achieve real-time response in milliseconds. When the load suddenly changes, it is entirely up to the diesel power station to deal with the sudden load change, and it is impossible to achieve true parallel operation. This method can be used for occasions where the load changes little; when the load suddenly changes or becomes larger, especially when it exceeds the rated output power of the diesel power station, it is easy to cause the diesel power station to overload protection, and long-term use accelerates the damage of the diesel power station. Another way is that the PCS uses a virtual synchronous machine to simulate the power generation process of the synchronous generator, so that its characteristics are consistent with the output characteristics of the diesel power station, and then achieve parallel operation. This method has obvious disadvantages. First, the virtual synchronous machine algorithm is extremely complex, and has high requirements for both the algorithm and hardware. It is currently immature and has few practical applications. Second, the virtual synchronous machine algorithm is not universal. When connected in parallel with a diesel power plant, it is adapted according to the rated power of the diesel power plant, etc., and cannot be connected in parallel with diesel power plants of different models and capacities.

[0004] In order to meet the needs of the current power grid and power-consuming equipment, mobile microgrids generally use AC230V / 400V for power supply. For this purpose, mobile microgrids are equipped with power conversion units PCS. At present, mobile power sources generally use traditional power sources-diesel power stations. In order to improve the power supply capacity and adaptability, diesel generator sets and mobile microgrids need to be powered in parallel. As a power electronic device, PCS has the characteristics of small inertia and fast response speed (millisecond level), but it has poor response to linear loads and nonlinear loads and poor overload resistance; while diesel power stations are large inertia generator equipment, which has a good support effect on nonlinear loads. Due to the different characteristics of PCS and diesel power stations, parallel power supply between them has always been a problem, and the purpose of real capacity expansion cannot be achieved. Summary of the invention

[0005] In view of the above analysis, an embodiment of the present invention aims to provide a method for controlling a mobile microgrid and a diesel power station in parallel, so as to solve the problem that when a sudden load change occurs in the existing power supply network connected in parallel with the mobile microgrid and the diesel power station, the adjustment speed is slow and the diesel power station is easily damaged.

[0006] On the one hand, an embodiment of the present invention provides a parallel control method for a mobile microgrid and a diesel power station, characterized in that the mobile microgrid and the diesel power station are connected in parallel to form a power supply network, wherein the PCS included in the mobile microgrid periodically adjusts the power output and repeats the following steps:

[0007] Sample the AC voltage and current on the load side and calculate the load active power and reactive power;

[0008] Based on the active power and reactive power of the load, the active power target and reactive power target of the PCS and diesel power station are calculated respectively;

[0009] According to the active power targets and reactive power targets of the PCS and the diesel power station, the active power target and reactive power target of the PCS are limited to obtain the expected active power and reactive power of the PCS;

[0010] Based on the PCS active power expectation and reactive power expectation, the PCS active power setting and reactive power setting are calculated, and then the active power deviation and reactive power deviation are calculated;

[0011] The power output is regulated based on the active power deviation and the reactive power deviation.

[0012] Based on the further improvement of the above method, the active power target and reactive power target of the PCS are calculated by the following method:

[0013] Pg=kp×Pload,where

[0014] Pg is the PCS active power target,

[0015] kp is the active slope,

[0016] Pload is the load active power;

[0017] Qg=kq×Qload, where

[0018] Qg is the PCS reactive power target,

[0019] kq is the reactive slope,

[0020] Qload is the reactive power of the load;

[0021] Wherein, the slope calculation method is: In the formula,

[0022] Pmg_e is the rated power of the mobile microgrid,

[0023] Pgen_e is the rated power of the diesel power station.

[0024] Based on the further improvement of the above method, the active power target and reactive power target of the diesel power station are calculated in the following way:

[0025] Pgen_g = (1-kp) × Pload, where Pgen_g is the active power target of the diesel power station;

[0026] Qgen_g=(1-kq)×Qload, where Qgen_g is the reactive power target of the diesel power station.

[0027] Based on the further improvement of the above method, the active power target of the PCS is limited to obtain the expected active power of the PCS, including:

[0028] If any of the following conditions is met, set the PCS active power expectation to any value within the range of 0 to the PCS active power target:

[0029] (1) The load active power is less than the minimum output power of the diesel power station.

[0030] (2) The active power target of the diesel power station is less than the minimum output power of the diesel power station;

[0031] If the PCS active power target is greater than the PCS maximum output power, then set the PCS active power expectation equal to the PCS maximum output power;

[0032] In other cases, set the PCS active power expectation equal to the PCS active power target.

[0033] Based on the further improvement of the above method, the reactive power target of the PCS is limited to obtain the expected reactive power of the PCS, including:

[0034] If the reactive power target of the diesel power station is greater than the maximum reactive power of the diesel power station,

[0035] Set the PCS reactive power expectation to the difference between the load reactive power and the maximum reactive power of the diesel power station;

[0036] If the PCS reactive power target is greater than the PCS maximum output power,

[0037] Then set the PCS reactive power expectation equal to the PCS maximum output power,

[0038] In other cases, set the PCS reactive power expectation equal to the PCS reactive power target.

[0039] Based on the further improvement of the above method, the PCS active power setting and reactive power setting are calculated in the following way:

[0040] Pref=P0+Pset,where:

[0041] Pref is the PCS active power setting,

[0042] P0 is the PCS active power reference,

[0043] Pset is the expected active power of PCS;

[0044] Qref=Q0+Qset,where

[0045] Qref is the PCS reactive power reference,

[0046] Q0 is the PCS reactive power reference,

[0047] Qset is the PCS reactive power expectation.

[0048] Based on the further improvement of the above method, the active power deviation and reactive power deviation are calculated in the following manner:

[0049] deltaP=Pref-Pms,where

[0050] deltaP is the active power deviation,

[0051] Pref is the PCS active power setting,

[0052] Pms is the PCS active power feedback;

[0053] deltaQ=Qref-Qms, where,

[0054] deltaQ is the reactive power deviation,

[0055] Qref is the PCS reactive power reference,

[0056] Qms is the PCS reactive power feedback.

[0057] Based on the further improvement of the above method, the power output is adjusted by respectively connecting the active power deviation and the reactive power deviation to the active power regulator and the reactive power regulator to calculate the duty cycle, outputting the control signal to the drive circuit for signal amplification, and then outputting it to the power conversion unit to control the adjusted power output.

[0058] Based on the further improvement of the above method, the duration of a single cycle of the cycle is determined by the PCS control frequency.

[0059] Another aspect of the present invention provides a power grid system for a mobile microgrid and a diesel power station in parallel that can quickly respond to sudden load changes, and is characterized by comprising:

[0060] Diesel power stations, operating as AC voltage sources;

[0061] Mobile microgrid, including electronic conversion unit PCS, microgrid energy management system EMS and energy storage system,

[0062] The PCS included in the mobile microgrid periodically adjusts the power output and repeats the following steps:

[0063] Sample the AC voltage and current on the load side and calculate the load active power and reactive power;

[0064] Based on the active power and reactive power of the load, the active power target and reactive power target of the PCS and diesel power station are calculated respectively;

[0065] According to the active power targets and reactive power targets of the PCS and the diesel power station, the active power target and reactive power target of the PCS are limited to obtain the expected active power and reactive power of the PCS;

[0066] Based on the PCS active power expectation and reactive power expectation, the PCS active power setting and reactive power setting are calculated, and then the active power deviation and reactive power deviation are calculated;

[0067] The power output is regulated based on the active power deviation and the reactive power deviation.

[0068] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0069] 1. The present invention continuously samples the AC voltage and current on the load side, calculates the load power change, and uses an original algorithm integrated in the PCS to apply the active slope and reactive slope. Based on the power relationship between the load, the mobile microgrid and the diesel power station, the PCS power deviation is quickly calculated, and millisecond-level rapid adjustment is achieved through the PCS to adapt to the parallel load changes of the mobile microgrid and the diesel power station, which greatly improves the load response capability and reduces the loss of the diesel power station caused by load mutation.

[0070] 2. The present invention gives full play to the respective advantages of PCS and diesel power station, i.e., PCS responds quickly, diesel power station has large inertia and strong adaptability to nonlinear loads, and no changes are required to the existing diesel power station. PCS only needs to add the load-side current detection function, no communication line parallel connection is required, and few hardware changes are required. It is suitable for PCS and diesel power stations of different capacity levels, and parallel connection can be achieved with simple configuration, which is simple, convenient and easy to achieve. It can truly achieve parallel expansion with millisecond-level real-time response to load mutation.

[0071] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] The accompanying drawings are only used for the purpose of illustrating specific embodiments and are not to be considered as limiting the present invention. In the entire drawings, the same reference symbols represent the same components;

[0073] Figure 1 This is the overall structure diagram of the parallel power supply network of the mobile microgrid and diesel power station.

[0074] Figure 2 This is a schematic diagram of the PCS control logic in the parallel power supply network of the mobile microgrid and diesel power station.

[0075] Figure 3 This is the flow chart of the PCS control adjustment algorithm. DETAILED DESCRIPTION

[0076] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0077] A specific embodiment of the present invention discloses a parallel control method for a mobile microgrid and a diesel power station, wherein the mobile microgrid and the diesel power station are connected in parallel to form a power supply network, wherein the PCS included in the mobile microgrid periodically adjusts the power output and repeats the following steps:

[0078] The mobile microgrid is connected in parallel with the diesel power station to form a power supply network, wherein the PCS included in the mobile microgrid periodically adjusts the power output and repeats the following steps:

[0079] Sample the AC voltage and current on the load side and calculate the load active power and reactive power;

[0080] Based on the active power and reactive power of the load, the active power target and reactive power target of the PCS and diesel power station are calculated respectively;

[0081] According to the active power targets and reactive power targets of the PCS and the diesel power station, the active power target and reactive power target of the PCS are limited to obtain the expected active power and reactive power of the PCS;

[0082] Based on the PCS active power expectation and reactive power expectation, the PCS active power setting and reactive power setting are calculated, and then the active power deviation and reactive power deviation are calculated;

[0083] The power output is regulated based on the active power deviation and the reactive power deviation.

[0084] Figure 1 The overall structure of the mobile microgrid and the diesel power station parallel power supply network of the present invention is shown, wherein the mobile microgrid is composed of an energy storage system, a power conversion unit PCS and an EMS.

[0085] Optionally, the mobile microgrid can be a distributed power generation system such as a photovoltaic power generation system and a wind power generation system.

[0086] Generally, the energy storage system is connected to the DC input side of the power conversion unit PCS, and the AC output side of the PCS supplies power to the outside and is connected to the AC bus. The distributed generation system can be connected to the DC side or the AC side of the PCS.

[0087] Specifically, in the present invention, the PCS adds a load-side AC voltage and current sampling circuit for sampling the load-side AC voltage and AC current.

[0088] Normally, the diesel power station supplies power in the form of a voltage source, establishes a stable AC voltage and frequency, generally AC380V / 50Hz, and supplies power to the AC load; when the mobile microgrid starts running, the PCS is connected to the diesel power station in a constant power mode, and supplies power to the AC load together with the diesel power station.

[0089] like Figure 2 As shown, in the parallel power grid of the mobile microgrid and the diesel power station in the embodiment of the present invention, the rated power of the mobile microgrid is Pmg_e, the maximum output power is Pmg_max, the rated power of the diesel power station is Pgen_e, the maximum reactive power ratio of the diesel power station is Qgen_per, and the minimum output power of the diesel power station is Pgen_min, which can be obtained by reading the configuration parameters of the mobile microgrid.

[0090] like Figure 3 As shown, the adjustment process is:

[0091] Step S1: Sample the AC voltage and current at the load side, and calculate the load active power and reactive power.

[0092] Specifically, the PCS collects the load-side AC voltage and AC current through the load-side AC voltage and current sampling circuit.

[0093] Preferably, the AC frequency fms, d-axis voltage ud, and q-axis voltage uq are calculated according to the collected load-side AC voltage and AC voltage according to a phase-locked loop algorithm; and the d-axis current id and q-axis current iq are calculated according to abc-dq transformation.

[0094] According to the formula: Pload = ud × id + uq × iq;

[0095] Qload = uq × id - ud × iq;

[0096] Calculate the load active power Pload and reactive power Qload.

[0097] Step S2: Calculate the active power target and reactive power target of the PCS and the diesel power station respectively based on the active power and reactive power of the load.

[0098] Further, the active power target and reactive power target of the PCS are calculated in the following manner:

[0099] Pg=kp×Pload,where

[0100] Pg is the PCS active power target,

[0101] kp is the active slope,

[0102] Pload is the load active power;

[0103] Qg=kq×Qload, where

[0104] Qg is the PCS reactive power target,

[0105] kq is the reactive slope,

[0106] Qload is the reactive power of the load;

[0107] Wherein, the slope calculation method is: In the formula,

[0108] Pmg_e is the rated power of the mobile microgrid,

[0109] Pgen_e is the rated power of the diesel power station.

[0110] Furthermore, the active power target and reactive power target of the diesel power station are calculated in the following manner:

[0111] Pgen_g = (1-kp) × Pload, where Pgen_g is the active power target of the diesel power station;

[0112] Qgen_g=(1-kq)×Qload, where Qgen_g is the reactive power target of the diesel power station.

[0113] Step S3: performing limit calculation on the active power target and reactive power target of the PCS.

[0114] Furthermore, the active power target of the PCS is limited to obtain the expected active power of the PCS, including:

[0115] If any of the following conditions is met, set the PCS active power expectation to any value within the range of 0 to the PCS active power target:

[0116] (1) The load active power is less than the minimum output power of the diesel power station.

[0117] (2) The active power target of the diesel power station is less than the minimum output power of the diesel power station;

[0118] If the PCS active power target is greater than the PCS maximum output power, then set the PCS active power expectation equal to the PCS maximum output power;

[0119] In other cases, set the PCS active power expectation equal to the PCS active power target.

[0120] Furthermore, the limiting of the reactive power target of the PCS to obtain the expected reactive power of the PCS includes:

[0121] If the reactive power target of the diesel power station is greater than the maximum reactive power of the diesel power station,

[0122] Set the PCS reactive power expectation to the difference between the load reactive power and the maximum reactive power of the diesel power station;

[0123] If the PCS reactive power target is greater than the PCS maximum output power,

[0124] Then set the PCS reactive power expectation equal to the PCS maximum output power,

[0125] In other cases, set the PCS reactive power expectation equal to the PCS reactive power target.

[0126] Specifically, if the load active power Pload is less than the minimum output power Pgen_min of the diesel power station, or the active power target Pgen_g of the diesel power station is less than the minimum output power Pgen_min of the diesel power station, then the expected active power Pset is set to a range of 0 to Pg.

[0127] Preferably, Pset is set to 0;

[0128] If the PCS active power target Pg is greater than the maximum output power Pmg_max, the PCS active power expectation Pset is set equal to the PCS maximum output power Pmg_max;

[0129] In other cases, the PCS expected active power Pset is set equal to the PCS expected active power Pg.

[0130] If the reactive power target Qgen_g of the diesel power plant is greater than the maximum reactive power Pgen_e×Qgen_per of the diesel power plant,

[0131] Then set the reactive power expectation Qset equal to Qload-Pgen_e×Qgen_per;

[0132] If the reactive power target Qg is greater than the PCS maximum output power Pmg_max,

[0133] Then set the PCS reactive power expectation Qset equal to Pmg_max;

[0134] In other cases, the expected reactive power Qset is set equal to the target reactive power Qg.

[0135] Step S4: Calculate the PCS active power setting and reactive power setting, and then calculate the active power deviation and reactive power deviation.

[0136] Further, the PCS active power setting and reactive power setting are calculated in the following manner:

[0137] Pref=P0+Pset, where

[0138] Pref is the PCS active power setting,

[0139] P0 is the PCS active power reference,

[0140] Pset is the expected active power of PCS;

[0141] Qref=Q0+Qset,where

[0142] Qref is the PCS reactive power reference,

[0143] Q0 is the PCS reactive power reference,

[0144] Qset is the PCS reactive power expectation.

[0145] Specifically, the PCS active power reference P0 and reactive power reference Q0 are obtained by reading PCS configuration parameters.

[0146] Further, the active power deviation and reactive power deviation are calculated in the following manner:

[0147] deltaP=Pref-Pms,where

[0148] deltaP is the active power deviation,

[0149] Pref is the PCS active power setting,

[0150] Pms is the PCS active power feedback;

[0151] deltaQ=Qref-Qms, where,

[0152] deltaQ is the reactive power deviation,

[0153] Qref is the PCS reactive power reference,

[0154] Qms is the PCS reactive power feedback.

[0155] Step S5: Regulating power output based on the active power deviation and the reactive power deviation.

[0156] Furthermore, the power output is regulated by respectively connecting the active power deviation and the reactive power deviation to the active power regulator and the reactive power regulator to calculate the duty cycle, outputting the control signal to the drive circuit for signal amplification, and then outputting it to the power conversion unit to control the regulated power output.

[0157] Furthermore, the control period is determined by the PCS control frequency.

[0158] On the other hand, the present invention provides a power grid system for a mobile microgrid and a diesel power station in parallel that can quickly respond to sudden load changes, comprising:

[0159] Diesel power stations, operating as AC voltage sources;

[0160] Mobile microgrid, including electronic conversion unit PCS, microgrid energy management system EMS and energy storage system,

[0161] The PCS included in the mobile microgrid periodically adjusts the power output and repeats the following steps:

[0162] Sample the AC voltage and current on the load side and calculate the load active power and reactive power;

[0163] Based on the active power and reactive power of the load, the active power target and reactive power target of the PCS and diesel power station are calculated respectively;

[0164] According to the active power targets and reactive power targets of the PCS and the diesel power station, the active power target and reactive power target of the PCS are limited to obtain the expected active power and reactive power of the PCS;

[0165] Based on the PCS active power expectation and reactive power expectation, the PCS active power setting and reactive power setting are calculated, and then the active power deviation and reactive power deviation are calculated;

[0166] The power output is regulated based on the active power deviation and the reactive power deviation.

[0167] The following is an example of the present invention:

[0168] Assuming the PCS control frequency is 10kHz, the delay is about 100us. The rated power of the mobile microgrid is Pmg_e=50kW, the maximum output power Pmg_max=50kW, the rated power of the diesel power station is Pgen_e=50kW, the maximum reactive power ratio of the diesel power station is Qgen_per=25%, and the minimum output power of the diesel power station is Pgen_min=5kW. The steady-state load active power Pload1=40kW, the reactive power Qload1=20kvar, the PCS active power output is P=20kW, the reactive power Q=10kvar; the diesel power station active power output Pgen=10kW, the reactive power Qgen=10kvar.

[0169] At a certain moment, the load increases to active power Pload=80kW and reactive power Qload=40kvar.

[0170] PCS reads the configuration parameters of the mobile microgrid, such as the rated power of the mobile microgrid is Pmg_e=50kW, the maximum output power is Pmg_max=50kW, the rated power of the diesel power station is Pgen_e=50kW, the maximum reactive power ratio of the diesel power station is Qgen_per=30%, and the minimum output power of the diesel power station is Pgen_min=5kW.

[0171] To start a control cycle, execute the following steps:

[0172] Step 1: PCS collects the load-side AC voltage and AC current through the load-side AC voltage and current sampling circuit, and calculates:

[0173] Load active power Pload1 = 80kW;

[0174] Reactive power Qload1 = 40 kvar;

[0175] Active slope kp = reactive slope

[0176] Step 2: Calculate the PCS active power target Pg and reactive power target Qg, and the diesel power station active power target Pgen_g and reactive power target Qgen_g according to the active power given calculation formula and reactive power given calculation formula. Calculate according to the active power given calculation formula and reactive power given calculation formula:

[0177] Pg=kp×Pload=0.5×80kW=40kW;

[0178] Qg=kq×Qload=0.5×40kvar=20kvar;

[0179] Pgen_g=(1-kp)×Pload=40kW;

[0180] Qgen_g=(1-kq)×Qload=20kvar.

[0181] Step 3: Calculate the limit of PCS active power Pg and reactive power Qg. The specific process is as follows:

[0182] If the load active power Pload is less than the minimum output power Pgen_min of the diesel power station, the expected active power Pset is set to 0;

[0183] If the diesel power station active power target Pgen_g is less than the diesel power station minimum output power Pgen_min, the active power expectation Pset is set to 0;

[0184] If the PCS active power target Pg is greater than the maximum output power Pmg_max, the active power expectation Pset is set equal to the maximum output power Pmg_max;

[0185] In other cases, the expected active power Pset is set equal to the expected active power Pg = 40kW;

[0186] If the reactive power target of the diesel power plant is greater than the maximum reactive power of the diesel power plant Pgen_e×Qgen_per, then the reactive power expectation Qset is set equal to Qload-(Pgen_e×Qgen_per)=40kvar-(30%×50kW)=25kvar;

[0187] If the reactive power target Qg is greater than the maximum output power Pmg_max, set the reactive power expectation Qset equal to Pmg_max;

[0188] In other cases, the expected reactive power Qset is set equal to the target reactive power Qg.

[0189] According to the above limit calculation principle, the PCS active power expectation and reactive power expectation in this example are finally set as:

[0190] Active power expectation Pset = active power target Pg = 40kW;

[0191] Reactive power expectation Qset = reactive power target Qg = 25 kvar.

[0192] Step 4: Calculate the active power given Pref and reactive power Qref, and then calculate the active power deviation deltaP and reactive power deviation deltaQ.

[0193] Read the configuration parameters active power reference P0 = 0kW and reactive power reference Q0 = 0kvar, and calculate the active power reference Pref and reactive power reference Qref according to the active power reference P0, reactive power reference Q0, active power expectation Pset, and reactive power expectation Qset. The calculation formula is as follows:

[0194] Pref=P0+Pset=0+40kW=40kW;

[0195] Qref=Q0+Qset=0+25kvar=25kvar.

[0196] Calculate the active power deviation deltaP and reactive power deviation deltaQ.

[0197] Read the PCS active power feedback Pms=P=20kW and reactive power feedback Qms=Q=10kvar. At this time, the active power and reactive power of the mobile microgrid have not changed. Calculate according to the following formula:

[0198] deltaP = Pref - Pms = 20kW;

[0199] deltaQ=Qref-Qms=15kvar.

[0200] Step 5: Connect the active power deviation deltaP and the reactive power deviation deltaQ to the power regulator to calculate the duty cycle, and send them to the power conversion unit through the drive circuit to perform energy conversion.

[0201] According to the experimental results, PCS is transformed and output after 10ms.

[0202] In summary, by detecting the load active power and load reactive power in each control cycle of the mobile microgrid PCS, calculating the PCS active power setting and reactive power setting, and then adjusting the active power and reactive power output of the mobile microgrid in real time, the active power and reactive power of the mobile microgrid can be evenly divided with the active power and reactive power of the diesel power station within several PCS control cycles, that is, milliseconds, to achieve the purpose of parallel operation of the mobile microgrid and the diesel power station in transient and steady-state time dimensions.

[0203] Those skilled in the art will appreciate that all or part of the processes of the above-mentioned embodiments can be implemented by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium, wherein the computer-readable storage medium is a disk, an optical disk, a read-only storage memory, or a random access memory, etc.

[0204] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for controlling a mobile microgrid and a diesel power station in parallel, characterized in that: The mobile microgrid is connected in parallel with the diesel power station to form a power supply network, wherein the PCS included in the mobile microgrid periodically adjusts the power output and repeats the following steps: Sample the AC voltage and current on the load side and calculate the load active power and reactive power; Based on the active power and reactive power of the load, the active power target and reactive power target of the PCS and diesel power station are calculated respectively; According to the active power targets and reactive power targets of the PCS and the diesel power station, the active power target and reactive power target of the PCS are limited to obtain the expected active power and reactive power of the PCS; Based on the PCS active power expectation and reactive power expectation, the PCS active power setting and reactive power setting are calculated, and then the active power deviation and reactive power deviation are calculated; The power output is regulated based on the active power deviation and the reactive power deviation.

2. A method for controlling parallel operation of a mobile microgrid and a diesel power station according to claim 1, characterized in that: The active power target and reactive power target of the PCS are calculated as follows: Pg=kp×Pload,where Pg is the PCS active power target, kp is the active slope, Pload is the load active power; Qg=kq×Qload, where Qg is the PCS reactive power target, kq is the reactive slope, Qload is the reactive power of the load; Wherein, the slope calculation method is: In the formula, Pmg_e is the rated power of the mobile microgrid, Pgen_e is the rated power of the diesel power station.

3. A method for controlling a mobile microgrid and a diesel power station in parallel according to claim 2, characterized in that: The active power target and reactive power target of the diesel power station are calculated as follows: Pgen_g = (1-kp) × Pload, where Pgen_g is the active power target of the diesel power station; Qgen_g=(1-kq)×Qload, where Qgen_g is the reactive power target of the diesel power station.

4. A method for controlling parallel operation of a mobile microgrid and a diesel power station according to claim 3, characterized in that: The step of limiting the active power target of the PCS to obtain the expected active power of the PCS includes: If any of the following conditions is met, set the PCS active power expectation to any value within the range of 0 to the PCS active power target: (1) The load active power is less than the minimum output power of the diesel power station. (2) The active power target of the diesel power station is less than the minimum output power of the diesel power station; If the PCS active power target is greater than the PCS maximum output power, then set the PCS active power expectation equal to the PCS maximum output power; In other cases, set the PCS active power expectation equal to the PCS active power target.

5. A method for controlling parallel operation of a mobile microgrid and a diesel power station according to claim 3, characterized in that: The limiting the reactive power target of the PCS to obtain the expected reactive power of the PCS includes: If the reactive power target of the diesel power station is greater than the maximum reactive power of the diesel power station, Set the PCS reactive power expectation to the difference between the load reactive power and the maximum reactive power of the diesel power station; If the PCS reactive power target is greater than the PCS maximum output power, Then set the PCS reactive power expectation equal to the PCS maximum output power, In other cases, set the PCS reactive power expectation equal to the PCS reactive power target.

6. A method for controlling parallel operation of a mobile microgrid and a diesel power station according to claim 1, characterized in that: The PCS active power setting and reactive power setting are calculated as follows: Pref=P0+Pset, where Pref is the PCS active power setting, P0 is the PCS active power reference, Pset is the expected active power of PCS; Qref=Q0+Qset,where Qref is the PCS reactive power reference, Q0 is the PCS reactive power reference, Qset is the PCS reactive power expectation.

7. The method for controlling the parallel operation of a mobile microgrid and a diesel power station according to claim 1, characterized in that: The active power deviation and reactive power deviation are calculated as follows: deltaP=Pref-Pms,where deltaP is the active power deviation, Pref is the PCS active power setting, Pms is the PCS active power feedback; deltaQ=Qref-Qms, where, deltaQ is the reactive power deviation, Qref is the PCS reactive power reference, Qms is the PCS reactive power feedback.

8. The method for controlling the parallel operation of a mobile microgrid and a diesel power station according to claim 1, characterized in that: The power output is regulated by respectively connecting the active power deviation and the reactive power deviation to the active power regulator and the reactive power regulator to calculate the duty cycle, outputting the control signal to the drive circuit for signal amplification, and then outputting it to the power conversion unit to control the regulated power output.

9. The method for controlling the parallel operation of a mobile microgrid and a diesel power station according to claim 1, characterized in that: The duration of a single cycle of the cycle is determined by the PCS control frequency.

10. A power grid system of a mobile microgrid and a diesel power station in parallel that can quickly respond to sudden load changes, characterized in that: include: Diesel power stations, operating as AC voltage sources; Mobile microgrid, including electronic conversion unit PCS, microgrid energy management system EMS and energy storage system, The PCS included in the mobile microgrid periodically adjusts the power output and repeats the following steps: Sample the AC voltage and current on the load side and calculate the load active power and reactive power; Based on the active power and reactive power of the load, the active power target and reactive power target of the PCS and diesel power station are calculated respectively; According to the active power targets and reactive power targets of the PCS and the diesel power station, the active power target and reactive power target of the PCS are limited to obtain the expected active power and reactive power of the PCS; Based on the PCS active power expectation and reactive power expectation, the PCS active power setting and reactive power setting are calculated, and then the active power deviation and reactive power deviation are calculated; The power output is regulated based on the active power deviation and the reactive power deviation.

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