Balance control method and system for active power, reactive power and low power factor of diesel-optical-storage micro-grid

Abstract

The invention discloses a diesel-optical-storage micro-grid active and reactive power and low power factor balance control method and system, and the method comprises the steps: collecting a current voltage value, a current frequency value and a current power factor value of a diesel generator through a power monitoring module when a high-power motor is loaded or unloaded, performing deviation calculation on the current voltage value of the generator, the current frequency value of the generator and the current power factor value of the generator to obtain a deviation calculation result; determining a control priority through a power balance control module, and determining a target instruction according to a deviation calculation result; and adjusting active power and reactive power output by the photovoltaic inverter and / or the energy storage converter through a PID regulator. The method can balance the active power, reactive power and low power factors of the generator of the micro-grid system, improves the stability and reliability of the diesel-optical-storage micro-grid power supply system, reduces the cost, and can be widely applied to the technical field of micro-grid power systems.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro-grid power systems, and in particular to a method and system for balancing active and reactive power and low power factor of a diesel-light-storage micro-grid. BACKGROUND

[0002] With the increasing use of renewable energy worldwide, multiple application scenarios such as photovoltaic, wind power generation and energy storage are encouraged and integrated into traditional hydroelectric and thermal power generation power systems to form a new type of power system. In the new type of power system, a diesel-light-storage micro-grid as a flexible distributed energy source is a small power system composed of distributed power sources such as diesel generators, solar photovoltaic inverters and battery energy storage converters, and by a power distribution system, power loads and a control system. It can generate power locally, consume, store and balance locally to maximize energy utilization.

[0003] Traditional micro-grid control systems use passive control strategies for control methods for loading and unloading of high-power loads and low-power factor characteristics. Either the power supply capacity is increased, such as using a larger capacity generator, or the capacitance compensation cabinet and other reactive compensation devices are increased, both of which greatly increase the cost of equipment. SUMMARY

[0004] The main purpose of the embodiments of the present application is to provide a method and system for balancing active and reactive power and low power factor of a diesel-light-storage micro-grid with multi-dimensional balance control.

[0005] To achieve the above purpose, one aspect of the embodiments of the present application provides a method for balancing active and reactive power and low power factor of a diesel-light-storage micro-grid. The method is applied to a diesel-light-storage micro-grid power supply system, which includes a diesel generator, a photovoltaic inverter, an energy storage converter and a high-power motor. The method includes the following steps:

[0006] When the high-power motor is loaded or unloaded, a power monitoring module is used to collect the current voltage value, current frequency value and current power factor value of the diesel generator, and to calculate the deviation of the current voltage value, current frequency value and current power factor value of the diesel generator to obtain a deviation calculation result.

[0007] A power balance control module is used to determine a control priority and a target instruction according to the deviation calculation result.

[0008] A PID regulator is used to adjust the active and reactive power output by the photovoltaic inverter and / or the energy storage converter according to the control priority and the target instruction.

[0009] In some embodiments, the deviation calculation result includes a first deviation calculation result and a second deviation calculation result, the deviation calculation on the generator current voltage value, the generator current frequency value and the generator current power factor value to obtain a deviation calculation result, specifically including:

[0010] determining a generator reference voltage value, a generator reference frequency value and a generator reference power factor value;

[0011] calculating a first deviation of the generator current voltage value from the generator reference voltage value, a second deviation of the generator current frequency value from the generator reference frequency value, and a third deviation of the generator current power factor value from the generator reference power factor value;

[0012] determining a reference value deviation range, comparing the first deviation, the second deviation and the third deviation with the reference value deviation range;

[0013] when the first deviation, the second deviation and the third deviation are all lower than the reference value deviation range, obtaining the first deviation calculation result;

[0014] when the first deviation, the second deviation and the third deviation are all higher than the reference value deviation range, obtaining the first deviation calculation result.

[0015] In some embodiments, the power balance control module determines a control priority, specifically including:

[0016] when the high-power motor is loaded, determining that controlling the active power and the reactive power output by the photovoltaic inverter is the first priority, and controlling the active power and the reactive power output by the energy storage converter is the second priority;

[0017] when the high-power motor is unloaded, determining that controlling the active power and the reactive power output by the energy storage converter is the first priority, and controlling the active power and the reactive power output by the photovoltaic inverter is the second priority.

[0018] In some embodiments, the deviation calculation result includes a first deviation calculation result, and the determination of the target instruction according to the deviation calculation result specifically includes:

[0019] when the high-power motor is loaded and the deviation calculation result is the first deviation calculation result, obtaining the photovoltaic inverter generated power and the photovoltaic inverter rated capacity;

[0020] comparing the photovoltaic inverter generated power and the photovoltaic inverter rated capacity through the power monitoring module;

[0021] If the photovoltaic inverter power is less than the photovoltaic inverter rated capacity, a first reactive power deficiency value of the diesel generator is calculated;

[0022] The power balance control module outputs a first reactive power target instruction and a first active power target instruction for controlling the photovoltaic inverter according to the first reactive power deficiency value.

[0023] In some embodiments, the PID regulator adjusts the active power and the reactive power output by the photovoltaic inverter and / or the energy storage converter according to the control priority and the target instruction, specifically:

[0024] The PID regulator adjusts the reactive power output value of the photovoltaic inverter to be equal to the first reactive power deficiency value according to the first reactive power target instruction, and adjusts the active power output value of the photovoltaic inverter to reach a maximum output value according to the first active power target instruction.

[0025] In some embodiments, after the PID regulator adjusts the reactive power output of the photovoltaic inverter to be equal to the first reactive power deficiency value according to the first reactive power target instruction, and adjusts the active power output of the photovoltaic inverter to reach a maximum output value according to the first active power target instruction, the method further comprises:

[0026] The power monitoring module calculates a deviation calculation result of the diesel generator after the initial adjustment by the PID regulator;

[0027] When the deviation calculation result is the first deviation calculation result, a second reactive power deficiency value of the diesel generator is calculated;

[0028] The energy storage converter power and the energy storage converter rated capacity are obtained;

[0029] The power monitoring module compares the energy storage converter power and the energy storage converter rated capacity;

[0030] If the energy storage converter power is less than the energy storage converter rated capacity, the power balance control module outputs a second reactive power target instruction for controlling the energy storage converter according to the second reactive power deficiency value.

[0031] The PID regulator adjusts the reactive power output value of the energy storage converter to be equal to the second reactive power deficiency value according to the second reactive power target instruction.

[0032] In some embodiments, the deviation calculation result includes a second deviation calculation result, and the determination of the target instruction according to the deviation calculation result is specifically:

[0033] When the large power motor is unloaded and the deviation calculation result is the second deviation calculation result, outputting, by the power balance control module, a third reactive power target instruction and a second active power target instruction for controlling the energy storage converter.

[0034] In some embodiments, the adjusting, by the PID regulator, the active power and the reactive power output by the photovoltaic inverter and / or the energy storage converter according to the control priority and the target instruction specifically comprises:

[0035] calculating a balance value control coefficient;

[0036] adjusting, by the PID regulator, the reactive power output value of the energy storage converter to zero according to the third reactive power target instruction and adjusting the active power output value of the energy storage converter to zero according to the second active power target instruction.

[0037] In some embodiments, after the adjusting, by the PID regulator, the reactive power output value of the energy storage converter to zero according to the third reactive power target instruction and adjusting the active power output value of the energy storage converter to zero according to the second active power target instruction, the method further comprises:

[0038] calculating, by the power monitoring module, a deviation calculation result of the diesel generator after the initial adjustment by the PID regulator;

[0039] When the deviation calculation result is the second deviation calculation result, outputting, by the power balance control module, a fourth reactive power target instruction for controlling the photovoltaic inverter;

[0040] adjusting, by the PID regulator, the reactive power output value of the photovoltaic inverter to decrease by the balance value control coefficient according to the fourth reactive power target instruction until the reactive power output value is zero.

[0041] To achieve the above object, another aspect of the embodiment of the present application proposes an active and reactive power and low power factor balance control system for a diesel-photovoltaic-storage micro-grid power supply system, which comprises a diesel generator, a photovoltaic inverter, an energy storage converter and a large power motor, an EMS energy management system, the diesel generator, the photovoltaic inverter, the energy storage converter and the large power motor are connected with the EMS energy management system, and the EMS energy management system comprises:

[0042] A power monitoring module is configured to collect current voltage, current frequency and current power factor of the diesel generator when the high-power motor is loaded or unloaded, and to perform deviation calculation on the current voltage, the current frequency and the current power factor to obtain a deviation calculation result.

[0043] A power balance control module is connected with the power monitoring module, configured to determine a control priority and determine a target instruction according to the deviation calculation result.

[0044] A PID regulator is connected with the power balance control module, configured to adjust active power and reactive power output by the photovoltaic inverter and / or the energy storage converter according to the control priority and the target instruction.

[0045] The present application has the following advantages: the active and reactive power and low power factor balance control method and system for the diesel-photovoltaic-energy storage micro-grid is based on the voltage, frequency and power factor of the diesel generator, and the deviation calculation result is obtained by comparing the voltage, frequency and power factor of the diesel generator with the designed voltage, frequency and power factor reference value. When the high-power motor is loaded or unloaded, the control priority of the photovoltaic inverter and the energy storage converter is determined, and the target instruction of the active and reactive power output by the photovoltaic inverter and the energy storage converter is determined according to the deviation calculation result. When the high-power motor is loaded, the insufficient active and reactive power of the generator and the voltage and frequency drop caused thereby are supplemented. When the high-power motor is unloaded, the surplus active and reactive power output by the photovoltaic inverter and the energy storage converter is adjusted back. The active and reactive power and low power factor balance of the generator in the micro-grid system is achieved, the stability and reliability of the diesel-photovoltaic-energy storage micro-grid power supply system are improved, and the cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following introduces the drawings needed to be used in the embodiments of the present application. It should be understood that the drawings introduced below are only for facilitating the clear description of some embodiments in the technical solutions of the present application, and other drawings can be obtained by those skilled in the art without any creative labor on the basis of these drawings.

[0047] Figure 1 The step flow chart of the active and reactive power and low power factor balance control method for the diesel-photovoltaic-energy storage micro-grid provided by an embodiment of the present application is shown in the figure.

[0048] Figure 2 The structural block diagram of the active and reactive power and low power factor balance control system for the diesel-photovoltaic-energy storage micro-grid provided by an embodiment of the present application is shown in the figure.

[0049] Figure 3 The structural block diagram of the active and reactive power and low power factor balance control system of the diesel-light-storage micro-grid provided for another embodiment of the present application is shown in FIG. 1. DETAILED DESCRIPTION

[0050] For the purpose of the present application, the technical solutions and advantages are more clearly and intelligibly, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application. When the following description relates to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary examples do not represent all embodiments consistent with the present application, and they are only examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0051] It can be understood that the terms "first", "second", and the like used in the present application can be used herein to describe various concepts, but unless specifically stated, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of the present application, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information. Depending on the context, the word "if" as used herein can be interpreted as "when" or "when" or "in response to determining".

[0052] The terms "at least one", "multiple", "each", "any" and the like used in the present application include one, two or more than two, multiple includes two or more than two, each refers to each of the corresponding multiple, and any refers to any one of the multiple.

[0053] With the increasing use of renewable energy around the world, multiple application scenarios such as photovoltaic, wind power and energy storage are encouraged, and are integrated into traditional hydroelectric and thermal power generation power systems to form a new type of power system. In the new type of power system, the diesel-light-storage micro-grid as a flexible distributed energy is a small power system composed of distributed power sources such as diesel generators, solar photovoltaic inverters, battery energy storage converters, and variable distribution systems, power loads and control systems. It can generate electricity locally, consume, store and balance locally to maximize energy utilization.

[0054] The diesel light storage micro-grid power supply system is based on diesel generator as a voltage source to construct the grid operation, based on the priority use of renewable energy solar photovoltaic power generation as green energy supplement, reduce the fuel cost of diesel generator set, the input of battery energy storage system is larger, when the solar photovoltaic power generation is surplus or insufficient, the charging and discharging function of the energy storage battery is fully played, the excess power is stored in the energy storage system battery when the photovoltaic power generation is surplus, and the battery is discharged to supplement the power output when the photovoltaic power generation is insufficient, thereby reducing the fuel cost and investment cost of the user's diesel generator. Since the high-power motor belongs to an inductive load, its loading and unloading will cause voltage and frequency to rise and drop suddenly and the power factor to be low. The conventional method is to increase the capacity of the generator to provide more active and reactive power output, or to add a capacitor cabinet and other reactive compensation devices to improve the power factor and stabilize the voltage, but both of them will greatly increase the equipment cost.

[0055] Therefore, the embodiment of the present application provides a diesel light storage micro-grid active and reactive power and low power factor balance control method, based on the voltage, frequency and power factor value of the diesel generator operation, and the designed voltage, frequency and power factor reference value, the deviation calculation result is obtained, when the high-power motor is loaded or unloaded, the control priority of the photovoltaic inverter and the energy storage converter is determined, and the target instruction of the active and reactive power output by the photovoltaic inverter and the energy storage converter is determined according to the deviation calculation result, the active and reactive power shortage of the generator and the voltage and frequency drop caused thereby are supplemented when the high-power motor is loaded, and the excess active and reactive power output by the photovoltaic inverter and the energy storage converter is adjusted back when the high-power motor is unloaded, so that the active and reactive power and low power factor balance of the micro-grid system generator is achieved, the stability and reliability of the diesel light storage micro-grid power supply system are improved, and the cost is reduced.

[0056] Referring to Figure 1 , Figure 1 The step flow chart of the diesel light storage micro-grid active and reactive power and low power factor balance control method provided by the embodiment of the present application, the embodiment of the present application provides a diesel light storage micro-grid active and reactive power and low power factor balance control method, which is applied to a diesel light storage micro-grid power supply system, the diesel light storage micro-grid power supply system includes a diesel generator, a photovoltaic inverter, an energy storage converter and a high-power motor, and can include but is not limited to the following steps S101 to S103.

[0057] S101, when the high-power motor is loaded or unloaded, the current voltage value, the current frequency value and the current power factor value of the diesel generator are collected by the power monitoring module, the current voltage value, the current frequency value and the current power factor value of the generator are calculated, and the deviation calculation result is obtained;

[0058] Specifically, the core of the reactive power control strategy of the embodiment of the present application is based on the voltage and power factor values of the diesel generator operation, and the core of the active power control strategy is the frequency value of the diesel generator operation as the core control parameter, and the difference between the three is monitored and calculated by the power monitoring module, and the calculation result is used to output the control coefficient of the active and reactive power of the generator of the balanced micro-grid system.

[0059] Further as an optional implementation, the deviation calculation result includes a first deviation calculation result and a second deviation calculation result, and the step of performing deviation calculation on the current voltage value of the generator, the current frequency value of the generator and the current power factor value of the generator to obtain the deviation calculation result can be further divided into the following steps S1011 to S1015:

[0060] S1011, determining the reference voltage value of the generator, the reference frequency value of the generator and the reference power factor value of the generator;

[0061] S1012, calculating the first deviation of the current voltage value of the generator and the reference voltage value of the generator, the second deviation of the current frequency value of the generator and the reference frequency value of the generator, and the third deviation of the current power factor value of the generator and the reference power factor value of the generator;

[0062] Specifically, the power monitoring module monitors and calculates the deviation between the current voltage value Gv of the diesel generator, the current frequency value Gfq of the generator and the current power factor value Gpf of the generator and the designed voltage, frequency and power factor reference value. For each parameter, the current measurement value is deviated from the corresponding reference value by the following formula to obtain the first deviation, the second deviation and the third deviation:

[0063] Deviation (%) = (current measurement value - reference value) / reference value * 100%

[0064] S1013, determining the reference value deviation range, and comparing the first deviation, the second deviation and the third deviation with the reference value deviation range;

[0065] Specifically, an allowed fluctuation range, i.e. the reference value deviation range, is set, which can be set according to actual needs. For example, the reference value deviation range can be set to ±2%, ±3% of the reference value, etc.

[0066] S1014, when the first deviation, the second deviation and the third deviation are all lower than the reference value deviation range, obtaining the first deviation calculation result;

[0067] Specifically, when the high-power motor is loaded, the active and reactive power demand of the load side increases suddenly, and this sudden increase in power demand exceeds the current instantaneous support capability of the generator, resulting in a momentary drop in system voltage, i.e., the current voltage value Gv of the generator is much lower than the reference voltage value of the generator - exceeding the reference value range of the hysteresis; due to the sudden increase in active power demand, the system frequency also drops instantaneously, i.e., the current frequency value Gfq of the generator is lower than the reference frequency value of the generator - exceeding the reference value range of the hysteresis; the load side absorbs a large amount of reactive power, and the system power factor is also deteriorated, i.e., the current power factor value Gpf of the generator is lower than the reference power factor value of the generator - exceeding the reference value range of the hysteresis. At this time, if the power monitoring module calculates the first deviation, the second deviation and the third deviation to be much lower than the reference value range of the hysteresis, the first deviation calculation result is obtained.

[0068] S1015, when the first deviation, the second deviation and the third deviation are all higher than the reference value range of the hysteresis, the first deviation calculation result is obtained.

[0069] Specifically, when the high-power motor is unloaded, the active and reactive power demand of the load side decreases suddenly, and this sudden decrease in power demand results in a surplus of active and reactive power output of the photovoltaic inverter and energy storage converter of the diesel-light storage micro-grid power supply system, and the voltage instantaneously rises, i.e., the current voltage value Gv of the generator is much higher than the reference voltage value of the generator - exceeding the reference value range of the hysteresis; due to the sudden excess of active power, the system frequency rises, i.e., the current frequency value Gfq of the generator is higher than the reference frequency value of the generator - exceeding the reference value range of the hysteresis, and even the power factor PF > 1. At this time, if the power monitoring module calculates the first deviation, the second deviation and the third deviation to be higher than the reference value range of the hysteresis, the second deviation calculation result is obtained.

[0070] S102, determining the control priority through the power balance control module, and determining the target instruction according to the deviation calculation result;

[0071] S103, adjusting the active and reactive power output by the photovoltaic inverter and / or the energy storage converter according to the control priority and the target instruction through the PID regulator.

[0072] Further as an optional implementation, the step of determining the control priority through the power balance control module can be further divided into the following steps S1021 and S1022:

[0073] S1021, when the high-power motor is loaded, determining the active and reactive power output by the photovoltaic inverter as the first priority, and determining the active and reactive power output by the energy storage converter as the second priority;

[0074] S1022, when the high-power motor is unloaded, determining that the active power and the reactive power output by the energy storage converter are the first priority, and the active power and the reactive power output by the photovoltaic inverter are the second priority.

[0075] Specifically, when the high-power motor is loaded, the power balance control module controls the active power and the reactive power output by the photovoltaic inverter as the first priority, and the active power and the reactive power output by the energy storage converter as the second priority, controls the active power output to support the drop of the generator frequency, and controls the reactive power output to support the shortage of the generator reactive power; when the high-power motor is unloaded, the power balance control module controls the active power and the reactive power output by the energy storage converter as the first priority, and the active power and the reactive power output by the photovoltaic inverter as the second priority, controls the active power output to reduce to inhibit the rise of the generator frequency, and controls the reactive power output to reduce to inhibit the rise of the generator voltage, so as to balance the active power and the reactive power of the generator and the low power factor of the diesel-photovoltaic-storage micro-grid power supply system, and make the whole diesel-photovoltaic-storage micro-grid power supply system stable and reliable.

[0076] Further, as an optional implementation, the deviation calculation result includes a first deviation calculation result, and the step of determining the target instruction according to the deviation calculation result can be further divided into the following steps A201 to A204:

[0077] A201, when the high-power motor is loaded and the deviation calculation result is the first deviation calculation result, obtaining the photovoltaic inverter generated power and the photovoltaic inverter rated capacity;

[0078] A202, comparing the photovoltaic inverter generated power and the photovoltaic inverter rated capacity by the power monitoring module;

[0079] A203, if the photovoltaic inverter generated power is less than the photovoltaic inverter rated capacity, calculating the first reactive power deficiency of the diesel generator;

[0080] A204, outputting the first reactive power target instruction and the first active power target instruction of the photovoltaic inverter by the power balance control module according to the first reactive power deficiency.

[0081] Further, as an optional implementation, the step of adjusting the active power and the reactive power output by the photovoltaic inverter and / or the energy storage converter according to the control priority and the target instruction by the PID regulator can be further divided into the following step A301:

[0082] A301, adjusting the reactive power output value of the photovoltaic inverter to equal the first reactive power deficiency value according to the first reactive power target instruction, and adjusting the active power output value of the photovoltaic inverter to reach the maximum output value according to the first active power target instruction.

[0083] Specifically, when a high-power motor is loaded, the active and reactive power demand of the load side increases suddenly, causing the voltage and frequency to drop momentarily, and the active and reactive power output of the generator is insufficient to support voltage and frequency stability. At this time, the power monitoring module collects and calculates the current voltage value Gv, the current frequency value Gfq and the current power factor value Gpf of the generator, which are all far below the reference value hysteresis range. The power balance control module controls the output of the photovoltaic inverter as the first priority, and the power factor PF design value is 0.8.

[0084] In some optional embodiments, first, the current state of the photovoltaic inverter is checked by the power monitoring module, and the photovoltaic inverter power Ppv is compared with the rated capacity Spv of the photovoltaic inverter. When the photovoltaic inverter power is less than the rated capacity of the photovoltaic inverter (Ppv < Spv), it means that the photovoltaic inverter still has surplus capacity that can be used to provide reactive power. Next, the total reactive power that the diesel generator currently needs to supplement, i.e. the first reactive power deficiency Gq, is calculated, and then the power balance control module is used to control the reactive power output value of the photovoltaic inverter to equal the first reactive power deficiency (Qpv = Gq), and the active power output value to reach the maximum output value (Ppv = 100%), after the initial adjustment by the PID regulator.

[0085] Further as an optional implementation, after step A301, the following steps A302 to A307 are further included:

[0086] A302, calculating the deviation calculation result of the diesel generator after the initial adjustment by the PID regulator by the power monitoring module;

[0087] A303, when the deviation calculation result is the first deviation calculation result, calculating the second reactive power deficiency of the diesel generator;

[0088] A304, obtaining the energy storage converter power and the rated capacity of the energy storage converter;

[0089] A305, comparing the energy storage converter power and the rated capacity of the energy storage converter by the power monitoring module;

[0090] A306, if the energy storage converter power is less than the rated capacity of the energy storage converter, outputting the second reactive power target instruction of the energy storage converter according to the second reactive power deficiency by the power balance control module;

[0091] A307、adjusting the reactive power output value of the energy storage converter to equal the second reactive power deficiency value according to the second reactive power target instruction through the PID regulator.

[0092] Specifically, after the initial adjustment by the PID regulator, the power monitoring module calculates whether the deviations of the voltage, frequency and power factor of the diesel generator from the reference values have met the reference value deviation range. If the deviations are still below the reference value deviation range, the power balance control module controls the output of the energy storage converter as the second priority.

[0093] In some optional embodiments, first, the state of charge of the energy storage converter is checked by the power monitoring module to set a safe discharge interval (e.g., 5% to 95%) and calculate whether the energy storage battery power SOC is within the set safe discharge interval. When the energy storage battery power SOC of the energy storage converter is within the set safe discharge interval, it indicates that the energy storage converter can participate in discharging. Next, it is calculated whether there is still a lack of reactive power of the diesel generator, i.e., the second reactive power deficiency value Gq'. The second reactive power deficiency value Gq' is calculated by the difference between the load-side demand reactive power Ql and the output reactive power Qpv of the photovoltaic inverter, i.e., Gq' = Ql - Qpv. Then, it is returned to the power monitoring module to check the current state of the energy storage converter and compare the current energy storage converter power Ppcs with the rated capacity Spcs of the energy storage converter. When the energy storage converter power is less than the rated capacity of the energy storage converter (Ppcs < Spcs), it indicates that the energy storage converter still has residual capacity and can be used to provide reactive power. Then, the power balance control module controls the output value of the reactive power of the energy storage converter to equal the second reactive power deficiency value (Qpcs = Gq'). After the adjustment by the PID regulator, the voltage, frequency and power factor caused by the loading of the high-power motor are recovered to the reference values more quickly.

[0094] Further as an optional implementation, the deviation calculation result includes a second deviation calculation result, and the step of determining the target instruction according to the deviation calculation result can be further divided into the following step B201:

[0095] B201, when the high-power motor is unloaded and the deviation calculation result is the second deviation calculation result, outputting a third reactive power target instruction and a second active power target instruction for controlling the energy storage converter through the power balance control module.

[0096] Further as an optional implementation, the step of adjusting the active power and reactive power output by the photovoltaic inverter and / or the energy storage converter according to the control priority and the target instruction through the PID regulator can be further divided into the following steps B301 and B302:

[0097] B301, calculating a balance value control coefficient;

[0098] B302, adjusting the reactive power output value of the energy storage converter to zero according to the third reactive power target instruction and adjusting the active power output value of the energy storage converter to zero according to the second active power target instruction through the PID regulator.

[0099] Specifically, when the high-power motor is unloaded, the active and reactive power output of the photovoltaic inverter and the energy storage converter of the diesel-light storage micro-grid system is surplus, the voltage and frequency are lifted, and even the power factor PF>1. At this time, the current voltage value Gv, the current frequency value Gfq and the current power factor value Gpf of the generator are all higher than the reference value hysteresis range calculated by the power monitoring module, and the power balance control module controls the output of the energy storage converter as the first priority. First, the control coefficient required to reach the balance value, i.e. the balance value control coefficient, is calculated by the power monitoring module, and the active power output value of the energy storage converter is controlled to zero (Ppcs=0) and the reactive power output value is controlled to zero (Qpcs=0) through the power balance control module, and the initial adjustment is completed through the PID regulator.

[0100] Further as an optional implementation, after step B302, the following steps B303 to B305 are further included:

[0101] B303, calculating the deviation calculation result of the diesel generator after the initial adjustment by the PID regulator through the power monitoring module;

[0102] B304, when the deviation calculation result is the second deviation calculation result, outputting the fourth reactive power target instruction for controlling the photovoltaic inverter through the power balance control module;

[0103] B305, adjusting the reactive power output value of the photovoltaic inverter to decrease according to the balance value control coefficient until the reactive power output value is zero according to the fourth reactive power target instruction through the PID regulator.

[0104] Specifically, after the initial adjustment by the PID regulator is completed, the power monitoring module calculates whether the deviation of the voltage, frequency and power factor of the diesel generator from the reference value has met the reference value hysteresis range, and if it is still higher than the reference value hysteresis range, the power balance control module controls the output of the photovoltaic inverter as the second priority. The reactive power output value Qpv of the photovoltaic inverter is controlled to decrease at a rate of the balance value control coefficient (such as 5% / s) through the power balance control module until the reactive power output value is zero (Qpv=0), and after the adjustment by the PID regulator is completed, the voltage surge and low power factor caused by the unloading of the high-power motor are quickly recovered to the reference value.

[0105] In summary, the power monitoring module monitors the key parameters of the diesel-light-storage micro-grid in real time in the control strategy operation. When the load of the high-power motor is continuously loaded and unloaded, the active and reactive power outputs of the photovoltaic inverter and the energy storage converter are balanced, so that the diesel-light-storage micro-grid system is balanced and stably and reliably operated.

[0106] The above describes the active and reactive power and low power factor balance control method of the diesel-light-storage micro-grid of the embodiment of the application. It can be recognized that, aiming at the power supply mode of the new type of power system of the micro-grid composed of the diesel generator, the solar photovoltaic inverter and the battery energy storage converter system and the operation demand of the high-power motor load, a control strategy for balancing the active and reactive power and the low power factor of the diesel-light-storage micro-grid power supply system is designed. The deviation calculation result is obtained based on the voltage, frequency and power factor values of the diesel generator operation and the designed voltage, frequency and power factor reference values. When the high-power motor is loaded, the active and reactive power output of the photovoltaic inverter is determined as the first priority, and the active and reactive power output of the energy storage converter is determined as the second priority. The active power output of the energy storage converter is controlled to support the drop of the generator frequency, and the reactive power output of the energy storage converter is controlled to support the insufficient reactive power of the generator. After the several hundred ms cycle adjustment by the PID regulator, the voltage, frequency and power factor values of the diesel-light-storage micro-grid system tend to be within the reference value±hysteresis range of the stable operation. When the high-power motor is unloaded, the active and reactive power output of the energy storage converter is determined as the first priority, and the active and reactive power output of the photovoltaic inverter is determined as the second priority. The active power output of the photovoltaic inverter is controlled to reduce to suppress the rise of the generator frequency, and the reactive power output of the photovoltaic inverter is controlled to reduce to suppress the rise of the generator voltage. After the several hundred ms cycle adjustment by the PID regulator, the voltage, frequency and power factor values of the diesel-light-storage micro-grid system tend to be within the reference value±hysteresis range of the stable operation. The problem of the sudden rise and drop of the voltage and frequency and the low power factor caused by the loading and unloading of the high-power motor load can be solved. The active and reactive power and the low power factor of the micro-grid system generator are balanced, the stability and reliability of the diesel-light-storage micro-grid power supply system are improved, and the cost is reduced.

[0107] Reference Figure 2 , Figure 2The structure block diagram of the active and reactive power and low power factor balance control system of the diesel-light storage micro-grid is provided for an embodiment of the present application, and the embodiment of the present application further provides an active and reactive power and low power factor balance control system of a diesel-light storage micro-grid, which is applied to a diesel-light storage micro-grid power supply system, and the diesel-light storage micro-grid power supply system comprises a diesel generator, a photovoltaic inverter, an energy storage converter and a high-power motor, comprises an EMS energy management system, the diesel generator, the photovoltaic inverter, the energy storage converter and the high-power motor are connected with the EMS energy management system, and the EMS energy management system comprises:

[0108] A power monitoring module is configured to collect a current voltage value, a current frequency value and a current power factor value of the diesel generator when the high-power motor is loaded or unloaded, perform deviation calculation on the current voltage value, the current frequency value and the current power factor value of the generator, and obtain a deviation calculation result;

[0109] A power balance control module is connected with the power monitoring module and is configured to determine a control priority and determine a target instruction according to the deviation calculation result;

[0110] A PID regulator is connected with the power balance control module and is configured to adjust active power and reactive power output by the photovoltaic inverter and / or the energy storage converter according to the control priority and the target instruction.

[0111] Specifically, the reactive power control strategy ensures voltage stability and power factor balance, and avoids problems such as loss of voltage and tripping caused by low voltage during starting of the high-power motor; the active power control strategy quickly adjusts the reactive power output by the photovoltaic inverter and the energy storage converter when the high-power motor is loaded, and insufficient adjustment or insufficient adjustment amount will lead to excessive surplus reactive power output, resulting in high voltage of the power grid, so the loading and unloading of the high-power motor requires the EMS energy management system to have active and reactive power control and low power factor control strategies to ensure stable and reliable operation of the diesel-light storage micro-grid system.

[0112] The strategy runs in the EMS energy management system composed of the power monitoring module, the power balance control module and the PID regulator, and controls the active and reactive power of the photovoltaic inverter and the energy storage converter through EMS strategy operation calculation, supplements the insufficient active and reactive power of the generator and leads to voltage and frequency drop when the high-power motor is loaded, and adjusts the surplus active and reactive power output by the photovoltaic inverter and the energy storage converter when the high-power motor is unloaded, thereby stabilizing the diesel-light storage micro-grid system.

[0113] Further, as Figure 3The EMS energy management system can further comprise an HMI human-machine interface connected with the power monitoring module and the power balance control module, and used for realizing user interaction and parameter setting, facilitating an operation and maintenance personnel to monitor a system state in real time, to adjust control strategy parameters, and to guarantee efficient and stable operation of the diesel-light-storage micro-grid.

[0114] The contents in the diesel-light-storage micro-grid active and reactive power and low power factor balance method embodiment are applicable to the diesel-light-storage micro-grid active and reactive power and low power factor balance system embodiment, the diesel-light-storage micro-grid active and reactive power and low power factor balance system embodiment specifically realizes the same functions as the diesel-light-storage micro-grid active and reactive power and low power factor balance method embodiment, and achieves the same beneficial effects as the diesel-light-storage micro-grid active and reactive power and low power factor balance method embodiment.

[0115] Further, the methods can be implemented in any type of computing platform operably connected to, including but not limited to, a personal computer, a mini-computer, a mainframe, a workstation, a network or distributed computing environment, a stand-alone or integrated computer platform, or in communication with a charged particle tool or other imaging device, and the like. Aspects of the present application can be implemented in machine-readable code stored on a non-transitory storage medium or device, whether removable or integrated to the computing platform, such as a hard disk, an optical read and / or write storage medium, RAM, ROM, and the like, such that it is readable by a programmable computer and, when the storage medium or device is read by the computer, is used to configure and operate the computer to perform the processes described herein. Further, the machine-readable code, or portions thereof, can be transmitted over wired or wireless networks. The present application described herein includes these and other different types of non-transitory computer readable storage media when such media include instructions or programs that implement the steps described above in conjunction with a microprocessor or other data processor. The present application also includes the computer itself when programmed in accordance with the methods and techniques described in the present application.

[0116] The computer program can be applied to input data to perform the functions described herein, thereby transforming the input data to generate output data stored to non-volatile memory. The output information can also be applied to one or more output devices, such as a display. In a preferred embodiment of the present application, the transformed data represents a physical and tangible object, including a specific visual depiction of the physical and tangible object produced on a display.

[0117] In the above description of the present specification, the description of the terms "one embodiment", "another embodiment", or "certain embodiments" or the like means that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Also, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in an appropriate manner.

[0118] Although embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and alterations can be made hereto without departing from the principles and spirit of the application, the scope of which is defined by the claims and their equivalents.

[0119] The above is a specific description of the preferred embodiments of the present application, but the present application is not limited to the embodiments, and those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present application, and these equivalent modifications or substitutions are included in the scope defined by the claims of the present application.

Claims

1. A method for balancing active power, reactive power and low power factor of a diesel-light-storage micro-grid, applied to a diesel-light-storage micro-grid power supply system, the diesel-light-storage micro-grid power supply system comprising a diesel generator, a photovoltaic inverter, an energy storage converter and a high-power motor, characterized in that, The method comprises the following steps: When the high-power motor is loaded or unloaded, the current voltage value, the current frequency value and the current power factor value of the diesel generator are collected by the power monitoring module, and the current voltage value, the current frequency value and the current power factor value of the generator are calculated to obtain the deviation calculation result; The control priority is determined by the power balance control module, and the target instruction is determined according to the deviation calculation result; The active power and the reactive power output by the photovoltaic inverter and / or the energy storage converter are adjusted by the PID regulator according to the control priority and the target instruction.

2. The method of claim 1, wherein, The deviation calculation result includes a first deviation calculation result and a second deviation calculation result, and the deviation calculation of the current voltage value, the current frequency value and the current power factor value of the generator is specifically as follows: The reference voltage value, the reference frequency value and the reference power factor value of the generator are determined; The first deviation between the current voltage value and the reference voltage value, the second deviation between the current frequency value and the reference frequency value, and the third deviation between the current power factor value and the reference power factor value are calculated; The reference value hysteresis range is determined, and the first deviation, the second deviation and the third deviation are compared with the reference value hysteresis range; When the first deviation, the second deviation and the third deviation are all lower than the reference value hysteresis range, the first deviation calculation result is obtained; When the first deviation, the second deviation and the third deviation are all higher than the reference value hysteresis range, the first deviation calculation result is obtained.

3. The method of claim 1, wherein, The control priority is determined by the power balance control module, and the target instruction is determined according to the deviation calculation result. When the high-power motor is loaded, the control of the active power and the reactive power output by the photovoltaic inverter is determined as the first priority, and the control of the active power and the reactive power output by the energy storage converter is determined as the second priority. When the high-power motor is unloaded, the control of the active power and the reactive power output by the energy storage converter is determined as the first priority, and the control of the active power and the reactive power output by the photovoltaic inverter is determined as the second priority.

4. The method of claim 1, wherein, The deviation calculation result includes a first deviation calculation result, and the target instruction is determined according to the deviation calculation result. When the high-power motor is loaded and the deviation calculation result is the first deviation calculation result, the photovoltaic inverter power generation and the photovoltaic inverter rated capacity are obtained. The photovoltaic inverter power generation and the photovoltaic inverter rated capacity are compared by the power monitoring module. If the photovoltaic inverter power generation is less than the photovoltaic inverter rated capacity, the first reactive power deficiency of the diesel generator is calculated. The first reactive power target instruction and the first active power target instruction for controlling the photovoltaic inverter are output by the power balance control module according to the first reactive power deficiency.

5. The method of claim 4, wherein, The PID regulator adjusts the active power and the reactive power output by the photovoltaic inverter and / or the energy storage converter according to the control priority and the target instruction, specifically: The PID regulator adjusts the reactive power output value of the photovoltaic inverter to the first reactive power deficiency value according to the first reactive power target instruction, and adjusts the active power output value of the photovoltaic inverter to the maximum output value according to the first active power target instruction.

6. The method of claim 5, wherein, After the PID regulator adjusts the reactive power output of the photovoltaic inverter to the first reactive power deficiency value according to the first reactive power target instruction, and adjusts the active power output of the photovoltaic inverter to the maximum output value according to the first active power target instruction, the method further comprises: The power monitoring module calculates the deviation calculation result of the diesel generator after the initial adjustment by the PID regulator; When the deviation calculation result is the first deviation calculation result, the second reactive power deficiency value of the diesel generator is calculated; The energy storage converter power generation and the energy storage converter rated capacity are obtained; The power monitoring module compares the energy storage converter power generation and the energy storage converter rated capacity; If the energy storage converter power generation is less than the energy storage converter rated capacity, the power balance control module outputs the second reactive power target instruction for controlling the energy storage converter according to the second reactive power deficiency value; The PID regulator adjusts the reactive power output value of the energy storage converter to the second reactive power deficiency value according to the second reactive power target instruction.

7. The method of claim 1, wherein, The deviation calculation result includes a second deviation calculation result, and the target instruction is determined according to the deviation calculation result, specifically: When the high-power motor is unloaded and the deviation calculation result is the second deviation calculation result, the power balance control module outputs the third reactive power target instruction and the second active power target instruction for controlling the energy storage converter.

8. The method of claim 7, wherein, The PID regulator adjusts the active power and the reactive power output by the photovoltaic inverter and / or the energy storage converter according to the control priority and the target instruction, specifically comprising: The balance value control coefficient is calculated; The PID regulator adjusts the reactive power output value of the energy storage converter to zero according to the third reactive power target instruction, and adjusts the active power output value of the energy storage converter to zero according to the second active power target instruction.

9. The method of claim 8, wherein, After the PID regulator adjusts the reactive power output value of the energy storage converter to zero according to the third reactive power target instruction, and adjusts the active power output value of the energy storage converter to zero according to the second active power target instruction, the method further comprises: The power monitoring module calculates the deviation calculation result of the diesel generator after the initial adjustment by the PID regulator; When the deviation calculation result is the second deviation calculation result, output a fourth reactive power target instruction for controlling the photovoltaic inverter by the power balance control module; Adjust the reactive power output value of the photovoltaic inverter according to the fourth reactive power target instruction by the PID regulator, and reduce the reactive power output value by the balance value control coefficient until the reactive power output value is zero.

10. An active and reactive power and low power factor balance control system for a diesel-light storage micro-grid power supply system, the diesel-light storage micro-grid power supply system comprising a diesel generator, a photovoltaic inverter, an energy storage converter and a high-power motor, characterized in that, The diesel generator, the photovoltaic inverter, the energy storage converter and the high-power motor are connected with an EMS energy management system, and the EMS energy management system comprises: A power monitoring module is configured to collect a current generator voltage value, a current generator frequency value and a current generator power factor value of the diesel generator when the high-power motor is loaded or unloaded, and perform deviation calculation on the current generator voltage value, the current generator frequency value and the current generator power factor value to obtain a deviation calculation result; A power balance control module is connected with the power monitoring module and configured to determine a control priority and determine a target instruction according to the deviation calculation result; A PID regulator is connected with the power balance control module and configured to adjust active power and reactive power output by the photovoltaic inverter and / or the energy storage converter according to the control priority and the target instruction.

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