A multi-scenario intelligent frequency converter based on double optimization control and a use method thereof

Abstract

The application provides a multi-scene intelligent frequency converter based on double optimization control and a use method thereof, comprising: a communication module, used for acquiring environment information corresponding to a current scene; a control module, used for generating a control voltage by using intelligent energy utilization control strategy based on grid input frequency and environment information; a frequency conversion module, used for adjusting output frequency based on the control voltage and sending the output frequency to a load under the scene; and the control voltage is used for adjusting the output frequency of the frequency converter by dynamic power control and power ramp rate control on the frequency converter; the communication module is added to the existing frequency converter to acquire external environment information; the control module is designed to perform dynamic power control on the frequency converter based on external grid input frequency and power ramp rate control on the frequency converter based on environment information, realize interaction between the frequency converter and the load and a regional control center system, and change the status that the existing frequency converter can only realize single frequency conversion by using initial parameters.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of heating, ventilation, air conditioning, water supply and drainage and other electrical energy-saving applications containing motor loads, and particularly relates to a multi-scene intelligent frequency converter based on double optimization control and a use method thereof. BACKGROUND

[0002] The frequency converter is an electric energy conversion device for converting power frequency power into another frequency power by using the on-off action of power semiconductor devices. The frequency drive technology is applied to change the frequency and amplitude of the working voltage of the AC motor load to adjust the speed and torque of the AC motor. At present, the frequency converter products on the market mainly provide voltage, current and frequency according to the characteristic parameters and operation requirements of the motor to control the motor to meet the requirements of the load. The commonly used control methods such as constant voltage frequency ratio control, vector control and direct torque control can be widely applied to fan and pump loads. There are many successful application cases in the fields of constant pressure water supply, various fans, central air conditioners and hydraulic pumps. In terms of structure, the frequency converter is mainly composed of rectification, inversion, drive, braking, filtering and pre-charging units. The frequency conversion mode of "AC-DC-AC" is adopted. The power frequency AC power of the power grid is first rectified into DC power, and then the DC power is inverted into AC power with adjustable frequency. The output voltage and frequency are adjusted by the on-off of the internal insulated gate bipolar transistor (IGBT). According to the actual needs of the motor, the required power voltage is provided to achieve the purpose of energy saving and speed regulation.

[0003] However, the general frequency converter on the market is only used as a power electronic device for terminal load control. The initial parameters are set according to the load to realize the frequency conversion and speed regulation function in a single working condition. The frequency converter product lacks the ability to perceive the grid and environmental information, and cannot be directly applied to the interactive operation of high-energy-consumption loads and the grid. Therefore, it is urgent to design a new type of frequency converter to better control the terminal load. SUMMARY

[0004] To overcome the shortcomings of the prior art, the application provides a multi-scene intelligent frequency converter based on double optimization control, which comprises a communication module, a control module and a frequency conversion module.

[0005] The communication module is used to obtain environmental information corresponding to the current scene.

[0006] The control module is used to generate a control voltage by using an embedded intelligent energy consumption control strategy based on the external grid input frequency and the environmental information.

[0007] The frequency conversion module is used to adjust the output frequency based on the control voltage and send the output frequency to each load in the scene.

[0008] The intelligent energy utilization control strategy determines a frequency correction error by introducing a rotational inertia of a virtual synchronous motor based on the grid input frequency; and calculates a frequency given by a frequency converter power ramp rate based on the environmental information;

[0009] The control voltage is generated based on the frequency correction error and the frequency given by the power ramp rate, and is used to adjust an output frequency of the intelligent frequency converter by dynamically controlling power of the intelligent frequency converter and controlling the power ramp rate.

[0010] Preferably, the scene includes a central air conditioner or a waterworks; the environmental information includes one or more of load information, load characteristics, energy utilization information, weather conditions, dates, and passenger flow in the scene; and the environmental information is provided by a regional central control system or a load central control system in the current scene.

[0011] Preferably, the control module includes a virtual inertia unit, a power ramp rate unit, a control given frequency unit, and a control voltage unit.

[0012] The virtual inertia unit is configured to determine whether to introduce a virtual inertia and determine a frequency correction error based on an external grid input frequency and a set threshold value.

[0013] The power ramp rate unit is configured to calculate a frequency given by a frequency converter power ramp rate based on the environmental information by using a power-frequency conversion control strategy.

[0014] The control given frequency unit is configured to add the frequency correction error and the frequency given by the frequency converter power ramp rate to obtain a control given frequency.

[0015] The control voltage unit is configured to calculate a control voltage based on the control given frequency by using a voltage-frequency conversion control strategy.

[0016] Preferably, the grid input frequency includes an alternating current frequency input by a grid.

[0017] Preferably, the virtual inertia unit is specifically configured to:

[0018] Determine a frequency fluctuation value based on a real-time alternating current frequency input by an external grid and a historical alternating current frequency.

[0019] Compare the frequency fluctuation value with a set frequency fluctuation threshold value to determine whether to introduce a rotational inertia of a virtual synchronous motor.

[0020] If the frequency fluctuation value exceeds the frequency fluctuation threshold value, a frequency correction error is calculated based on the real-time alternating current frequency by introducing the rotational inertia of the virtual synchronous motor; otherwise, the rotational inertia of the virtual synchronous motor is not introduced, and the frequency correction error is a set value.

[0021] Preferably, the frequency correction error is calculated as follows:

[0022]

[0023] where Δf is the frequency correction error, and Δω is the angular frequency difference;

[0024] The angular frequency difference Δω is calculated as follows:

[0025]

[0026] where J is the introduced virtual synchronous motor moment of inertia, J0 is the initial value of the virtual synchronous motor moment of inertia, k a is the angular frequency change coefficient.

[0027] Preferably, the power ramp rate unit is specifically used for:

[0028] inputting environmental information as an inertia into a calculation formula of the ramp rate to obtain a frequency converter power ramp rate;

[0029] inputting the frequency converter power ramp rate into a calculation formula of a frequency converter given power to obtain a frequency converter actual given power;

[0030] based on the frequency converter actual given power, using a power frequency conversion control strategy to calculate a frequency converter power ramp rate given frequency.

[0031] Preferably, the frequency converter power ramp rate given frequency is calculated as follows:

[0032] f ref = x1 ± k p P ref

[0033] where f ref is the frequency converter power ramp rate given frequency, x1 is a first calculation coefficient, k p is a power coefficient, and P ref is the frequency converter actual given power;

[0034] where the frequency converter actual given power P ref is calculated as follows:

[0035] P ref = GP ref0

[0036] where G is the frequency converter power ramp rate, and P ref0 is the initial given power of the frequency converter;

[0037] The frequency converter power ramp rate G is calculated as follows:

[0038]

[0039] wherein k is a proportional coefficient, x2 is a second calculation coefficient, I PMV is an inertia of environmental information, s is a Laplace operator, preferably, the control voltage is calculated according to the following formula:

[0040] V M = af+b

[0041] wherein V M is a control voltage, a and b are setting coefficients, and f is a control given frequency.

[0042] Preferably, the communication module comprises one or more of CAN and RS-485 communication protocols, and supports multiple data receiving and transmitting baud rates.

[0043] Preferably, the communication module is further configured to acquire regulation information of a superior master grid of each load in a scene, and send inverter state information to the superior master grid.

[0044] The control module is further configured to perform demand response based on the regulation information of the superior master grid, and generate inverter state information.

[0045] The regulation information of the superior master grid comprises power regulation information of a power master grid.

[0046] Preferably, the control module further comprises a demand response unit.

[0047] The demand response unit is specifically configured to control the frequency conversion module to change an output frequency based on the regulation information of the superior master grid, and acquire and generate inverter state information based on the output frequency of the frequency conversion module and a bus voltage.

[0048] Based on the same inventive concept, the application further provides a use method of a multi-scene intelligent inverter based on double optimization control, comprising:

[0049] Acquiring environmental information corresponding to a current scene and an external power grid input frequency through a communication module;

[0050] Generating a control voltage by using an embedded intelligent energy consumption control strategy based on the power grid input frequency and the environmental information through a control module;

[0051] Adjusting an output frequency based on the control voltage through a frequency conversion module, and sending the output frequency to each load in the scene;

[0052] The intelligent energy utilization control strategy determines a frequency correction error by introducing a rotational inertia of a virtual synchronous motor based on the grid input frequency; and calculates a frequency given by a frequency converter power ramp rate based on the environmental information;

[0053] The control voltage is generated based on the frequency correction error and the frequency given by the frequency converter power ramp rate, and is used to adjust the output frequency of the intelligent frequency converter by dynamically controlling the power of the intelligent frequency converter and controlling the power ramp rate.

[0054] The intelligent frequency converter is a multi-scenario intelligent frequency converter based on double optimization control.

[0055] Preferably, the control module generates a control voltage based on the grid input frequency and the environmental information using an embedded intelligent energy utilization control strategy, which includes:

[0056] The virtual inertia unit determines whether to introduce virtual inertia and determines a frequency correction error based on the external grid input frequency and a set threshold value.

[0057] The power ramp rate unit calculates a frequency given by a frequency converter power ramp rate based on the environmental information using a power-frequency conversion control strategy.

[0058] The control given frequency unit adds the frequency correction error and the frequency given by the frequency converter power ramp rate to obtain a control given frequency.

[0059] The control voltage unit calculates a control voltage based on the control given frequency using a voltage-frequency conversion control strategy.

[0060] The grid input frequency includes the AC input frequency of the grid; the environmental information includes one or more of the following in a scenario: load information, load characteristics, energy utilization information, weather conditions, dates, and passenger flow.

[0061] Preferably, the determination of whether to introduce virtual inertia and the determination of a frequency correction error based on the external grid input frequency and a set threshold value include:

[0062] Determine a frequency fluctuation value based on the real-time AC frequency and the historical AC frequency of the external grid input.

[0063] Compare the frequency fluctuation value with a set frequency fluctuation threshold value to determine whether to introduce the rotational inertia of the virtual synchronous motor.

[0064] If the frequency fluctuation value exceeds the frequency fluctuation threshold value, calculate a frequency correction error based on the real-time AC frequency by introducing the rotational inertia of the virtual synchronous motor; otherwise, do not introduce the rotational inertia of the virtual synchronous motor, and the frequency correction error is a set value.

[0065] Preferably, the frequency correction error is calculated as follows:

[0066]

[0067] where Δf is the frequency correction error, and Δω is the angular frequency difference;

[0068] The angular frequency difference Δω is calculated as follows:

[0069]

[0070] where J is the introduced virtual synchronous motor moment of inertia, J0 is the initial value of the virtual synchronous motor moment of inertia, k a is the angular frequency change coefficient.

[0071] Preferably, the power frequency conversion control strategy is used to calculate the frequency given by the frequency converter power ramp rate based on the environmental information, including:

[0072] The environmental information is input as the inertia into the calculation formula of the ramp rate to obtain the frequency converter power ramp rate;

[0073] The frequency converter power ramp rate is input into the calculation formula of the given power of the frequency converter to obtain the actual given power of the frequency converter;

[0074] Based on the actual given power of the frequency converter, the power frequency conversion control strategy is used to calculate the frequency given by the frequency converter power ramp rate.

[0075] Preferably, the frequency given by the frequency converter power ramp rate is calculated as follows:

[0076] f ref = x1 ± k p P ref

[0077] where f ref is the frequency given by the frequency converter power ramp rate, x1 is the first calculation coefficient, k p is the power coefficient, and P ref is the actual given power of the frequency converter;

[0078] where the actual given power P ref of the frequency converter is calculated as follows:

[0079] P ref = GP ref0

[0080] where G is the frequency converter power ramp rate, and P ref0 is the initial given power of the frequency converter;

[0081] The frequency converter power ramp rate G is calculated as follows:

[0082]

[0083] In the formula, k is a proportional coefficient, x2 is a second calculation coefficient, I PMV is the inertia of environmental information, and s is a Laplace operator.

[0084] Preferably, the method further comprises:

[0085] obtaining, by the communication module, regulation information of a superior main grid of each load in the scene;

[0086] controlling, by the control module, the frequency conversion module to change the output frequency based on the regulation information;

[0087] generating, by the control module, frequency converter state information based on the output frequency of the frequency conversion module and the bus voltage;

[0088] sending, by the communication module, the frequency converter state information to the superior main grid.

[0089] Compared with the closest prior art, the present application has the following beneficial effects:

[0090] 1. The present application provides a multi-scene intelligent frequency converter based on double optimization control and a use method thereof, comprising: a communication module, a control module and a frequency conversion module; the communication module is used to obtain environmental information corresponding to the current scene; the control module is used to generate a control voltage based on the external grid input frequency and the environmental information by using an embedded intelligent energy utilization control strategy; the frequency conversion module is used to adjust the output frequency based on the control voltage and send the output frequency to each load in the scene; the intelligent energy utilization control strategy determines a frequency correction error by introducing the rotational inertia of a virtual synchronous motor based on the grid input frequency; and calculates a frequency converter power ramp rate given frequency based on the environmental information; the control voltage is generated based on the frequency correction error and the power ramp rate given frequency, and is used to adjust the output frequency of the intelligent frequency converter by dynamically controlling the power of the intelligent frequency converter and controlling the power ramp rate; the present application adds a communication module to the existing frequency converter, which can obtain environmental information from the outside; the present application designs a control module embedded with an intelligent energy utilization control strategy, which can dynamically control the power of the frequency converter based on the external grid input frequency and control the power ramp rate of the frequency converter based on the environmental information, thereby adjusting the output frequency of the frequency converter, which helps to realize the interaction between the frequency converter and the load and the regional control center system, and changes the current situation that the existing frequency converter can only use initial parameters to realize single frequency conversion;

[0091] 2、The multiple-scene intelligent frequency converter based on double optimization control can be applied to multiple scenes including central air conditioners and water supply plants; the communication module provided by the application is used to acquire the superior master network regulation and control information of each load in the scene, and the control module is used to realize the demand response of the regulation and control information. BRIEF DESCRIPTION OF DRAWINGS

[0092] Figure 1 A structure schematic diagram of the multiple-scene intelligent frequency converter based on double optimization control is provided in the application;

[0093] Figure 2 A smart regulation and control strategy flow schematic diagram of the multiple-scene intelligent frequency converter based on double optimization control applied to a central air conditioner scene is provided in the application;

[0094] Figure 3 An information flow schematic diagram of the multiple-scene intelligent frequency converter based on double optimization control applied to a central air conditioner scene is provided in the application;

[0095] Figure 4 An information flow schematic diagram of the multiple-scene intelligent frequency converter based on double optimization control applied to a water supply system scene is provided in the application;

[0096] Figure 5 A use method flow schematic diagram of the multiple-scene intelligent frequency converter based on double optimization control is provided in the application. DETAILED DESCRIPTION

[0097] The application designs a multiple-scene intelligent frequency converter based on double optimization control (hereinafter referred to as an intelligent frequency converter), which has communication interaction, intelligent information sensing capability, dynamic power control and power ramp rate control capability, and is embedded with a smart energy control strategy considering the constraints of passenger flow and comfort; the intelligent frequency converter can realize the adjustable and controllable operation of terminal loads and the interactive operation with the power grid, activates the adjustable potential of terminal load power consumption, and helps to further realize the interactive operation and integrated collaborative control of power consumption load and the power grid and emergency management.

[0098] The specific embodiments of the application will be further described in detail below with reference to the accompanying drawings.

[0099] Embodiment 1

[0100] The structure schematic diagram of the multiple-scene intelligent frequency converter based on double optimization control provided by the application is shown in Figure 1 The structure schematic diagram of the multiple-scene intelligent frequency converter based on double optimization control provided by the application is shown in

[0101] The communication module is used to acquire the environment information corresponding to the current scene;

[0102] The control module is configured to generate a control voltage based on an external power grid input frequency and the environmental information by using an embedded intelligent energy utilization control strategy.

[0103] The frequency conversion module is configured to adjust an output frequency based on the control voltage and send the output frequency to each load in the scene.

[0104] The intelligent energy utilization control strategy is configured to determine a frequency correction error by introducing a rotational inertia of a virtual synchronous motor based on the power grid input frequency, and calculate a frequency given by a power ramp rate based on the environmental information.

[0105] The control voltage is generated based on the frequency correction error and the frequency given by the power ramp rate, and is configured to adjust the output frequency of the intelligent frequency converter by dynamically controlling the power of the intelligent frequency converter and controlling the power ramp rate.

[0106] The frequency conversion module is a common frequency converter on the market, and the specific structure, component devices and connection relationship are the same as those of the existing frequency converter, which should be understood by those skilled in the art.

[0107] The frequency conversion module includes a rectifier unit, a pre-charge unit, a filter unit, a braking unit, an inverter unit and a drive board.

[0108] The rectifier unit, the pre-charge unit, the filter unit, the braking unit and the inverter unit are connected in sequence. The rectifier unit is connected with the external power grid, and the inverter unit is connected with the motor load. The drive board is connected with the braking unit and the inverter unit respectively.

[0109] The drive board is configured to receive and send a braking signal (Brk) to IGBT in the braking unit and a control signal (S1-S6) to each IGBT in the inverter unit based on the control voltage provided by the control module, and adjust the output frequency by opening and closing each IGBT.

[0110] The filter unit is composed of two series-connected capacitors. The lines where the two capacitors are located are the DC bus of the intelligent frequency converter, and the control module obtains the bus voltage of the frequency conversion module from the DC bus.

[0111] The communication module is respectively connected with the upper master network of each load in the scene, the regional central control system in the current scene and the control module. The communication module has multiple communication protocols such as CAN and RS-485, supports multiple data transmission baud rates, and can perform bidirectional data transmission through the communication interface of the communication module.

[0112] The bidirectional data transmission includes:

[0113] Receive the regulation information of the upper master grid, and transmit the regulation information to the control module, so that the control module can adjust its working state according to the regulation information, and then control the frequency conversion module to change the output frequency to adapt to the load demand response;

[0114] The control module feeds back the real-time state information of the intelligent frequency converter to the upper master grid regulation through the communication interface, so as to facilitate the upper power grid to monitor the running state (including output power) of the intelligent frequency converter, and realize the interactive operation of the upper power grid and the intelligent frequency converter;

[0115] The regulation information of the upper master grid includes the regulation information of the power master grid, large traffic stations, and buildings.

[0116] Among them, the demand response is carried out through the demand response unit in the control module, specifically: based on the regulation information of the upper master grid, the frequency conversion module changes the output frequency; based on the output frequency and bus voltage of the frequency conversion module, the real-time state information of the intelligent frequency converter is generated.

[0117] The communication module contains a general information transmission interface and has a standard communication protocol form, which can be directly connected with the regional center control system and the load central control system, and obtain the environmental information corresponding to the current scene from the regional center control system and the load central control system;

[0118] The scene includes a central air conditioning system, a water supply system / running water plant, etc.; the environmental information includes one or more of the following: load information, load characteristics, energy consumption information, weather conditions, dates, and passenger flow in the scene.

[0119] The control module includes the following four units: a virtual inertia unit, a power ramp rate unit, a control given frequency unit, and a control voltage unit.

[0120] The virtual inertia unit is specifically used for:

[0121] Real-time detection of the frequency of alternating current input by the external power grid, and determination of the frequency fluctuation value based on the historical frequency of alternating current;

[0122] Compare the frequency fluctuation value with the set frequency fluctuation threshold value to determine whether the frequency fluctuation value exceeds the set frequency fluctuation threshold value, and select whether to introduce the rotational inertia (virtual inertia) of the virtual synchronous motor;

[0123] If the frequency fluctuation value exceeds the frequency fluctuation threshold value, calculate the frequency correction error based on the real-time frequency of alternating current by introducing the rotational inertia of the virtual synchronous motor; otherwise, do not introduce the rotational inertia of the virtual synchronous motor, and the frequency correction error is a set value 0, that is, the frequency of the output voltage of the intelligent frequency converter is only subject to the given frequency f ref Control.

[0124] The frequency correction error is calculated according to the following formula:

[0125]

[0126] In the formula, Δf is the frequency correction error, and Δω is the angular frequency difference value;

[0127] The angular frequency difference value Δω is calculated according to the following formula:

[0128]

[0129] In the formula, J is the introduced virtual synchronous motor moment of inertia, J0 is the initial value of the moment of inertia of the virtual synchronous motor, k a is the angular frequency change coefficient.

[0130] The power ramp rate unit is specifically configured to:

[0131] The environmental information is input into the calculation formula of the ramp rate as the inertia to obtain the frequency converter power ramp rate;

[0132] The frequency converter power ramp rate is input into the calculation formula of the frequency converter given power to obtain the frequency converter actual given power;

[0133] Based on the frequency converter actual given power, the frequency converter power ramp rate given frequency is calculated by using the power frequency conversion control strategy.

[0134] The frequency converter power ramp rate given frequency is calculated according to the following formula:

[0135] f ref =x1±k p P ref

[0136] In the formula, f ref is the frequency converter power ramp rate given frequency, x1 is the first calculation coefficient, k p is the power coefficient, and P ref is the frequency converter actual given power;

[0137] In the formula, the frequency converter actual given power P ref is calculated according to the following formula:

[0138] P ref =GP ref0

[0139] In the formula, G is the frequency converter power ramp rate, and P ref0 is the initial given power of the frequency converter;

[0140] The frequency converter power ramp rate G is calculated according to the following formula:

[0141]

[0142] In the formula, k is a proportional coefficient, x2 is a second calculation coefficient, I PMV is the inertia of environmental information, and s is a Laplace operator.

[0143] The control given frequency unit is used for adding the frequency correction error and the frequency converter power ramp rate given frequency to obtain a control given frequency.

[0144] The frequency correction error Δf generated by introducing the virtual inertia is directly added to the frequency converter power ramp rate given frequency f ref The control given frequency f is generated as shown in the following formula:

[0145] f = f ref + Δf

[0146] The control voltage unit is used for calculating a control voltage based on the control given frequency by using a voltage frequency conversion control strategy; in the process that the output frequency of the frequency converter rises from 0 Hz to a basic frequency, the output voltage (i.e., the control voltage) rises to a V / f line of a maximum output voltage in direct proportion, which is called a basic V / f line, and the output voltage and the frequency are in a proportional relationship, and the characteristic equation of the two can be expressed as:

[0147] V M = af + b

[0148] In the formula, V M is the control voltage, and a and b are set coefficients, which can be obtained by an aggregation method.

[0149] The present application provides a multi-scene intelligent frequency converter based on double optimization control, which contains a bidirectional data communication module with CAN, RS-485 and other communication protocols, can perform bidirectional data transmission, and supports multiple data transmission and reception baud rates; the intelligent frequency converter can detect the frequency of alternating current input by the external power grid in real time, perform deviation threshold judgment, introduce virtual inertia, realize dynamic power control, and realize intelligent power grid information, weather conditions, dates, and environmental information such as passenger flow; the different inertia converted from the environmental information is used for power ramp rate inertia control, and intelligent frequency converter intelligent ramp operation is realized. The intelligent frequency converter designed by the present application has communication interaction demand response, power dynamic control, and intelligent power ramp control considering passenger flow, energy consumption and other constraints, can be applied to central air conditioning systems, water supply systems / tap water plants and other scenes, can activate the adjustable potential of terminal load power consumption, realizes intelligent regulation and control and interactive operation of terminal power load, and is helpful to realize flexible interaction of "source network load storage".

[0150] Example 2:

[0151] The embodiment introduces application of a multi-scene intelligent frequency converter based on double optimization control. In the embodiment, the intelligent frequency converter is applied to a central air conditioning scene of a station. The regional center control system of the scene is a station center control system. The regulation and control information of the upper master network is a station regulation and control information. The load is a chilled water pump of the central air conditioning.

[0152] The control module of the intelligent frequency converter is embedded with an intelligent energy utilization control strategy (i.e. an intelligent regulation and control strategy). Figure 2 As shown in the figure, the weather condition, the date, the train information, the number of people in the waiting room and other environmental information are acquired from the station center control system through the communication module. The power regulation and control information (i.e. the power grid information in the figure) of the upper master network is acquired from the upper master network. The external information sensing of the intelligent frequency converter is realized through the communication module. The acquired information is sent to the control module.

[0153] The influence of the environmental information on the power of the central air conditioning is as follows.

[0154] The weather condition. According to the temperature condition and the sunny or rainy condition, the refrigeration / heating power of the central air conditioning is controlled.

[0155] The date. The working mode of the central air conditioning is different with different dates. For example, heating is needed in January and refrigeration is needed in July. In addition, the output power of the central air conditioning is different because the number of people is different on weekends / holidays and weekdays.

[0156] The train information. The train information includes the on-time or late condition of the train. When the train is late, the central air conditioning needs to work for a long time to ensure the temperature of the waiting room. When there is no train, the power of the central air conditioning is appropriately reduced or the central air conditioning is stopped to save energy.

[0157] The number of people in the waiting room. When the number of people in the waiting room is large, the power of the central air conditioning needs to be increased. Conversely, the power of the central air conditioning is reduced.

[0158] Figure 2 In the control module, the power ramp rate unit is used to realize the calculation of the power ramp rate control and generate the given frequency f ref of the power ramp rate of the frequency converter.

[0159] Specifically, the power ramp rate unit inputs the environment information into a calculation formula of the ramp rate according to the environment information provided by the communication module (in this embodiment, the central air conditioner of the station, i.e. the human comfort degree is calculated according to the weather condition, date, train information, number of people in the waiting room and other environment information, different human comfort degrees are converted into different inertias, and the frequency converter power ramp rate is calculated according to the inertia); then the obtained frequency converter power ramp rate is used to calculate the actual given power P ref of the frequency converter by using a calculation formula of the ramp link; finally, the frequency converter power ramp rate given frequency f ref is calculated by P / f control. The calculation formula of the frequency converter power ramp rate given frequency f ref is as follows:

[0160] Based on the weather condition, date, train information, number of people in the waiting room and other information, different human comfort degrees are converted into different inertias, and the human comfort degree can be calculated according to the following formula:

[0161]

[0162] In the formula, PMV is an evaluation index of human thermal response (human comfort degree), T sk is the average skin temperature, which is 306.65 K in this embodiment, D1 and D2 are the first and second area coefficients, T z is the indoor temperature, T m is the surface temperature of the heat material, T z and T m are related to the cold / heat power flow of the building, which can be obtained by an equivalent building heat model, M0 is the metabolic rate, which is 70.6 W / m 2 in this embodiment, I cl is the basic thermal resistance of clothing, which is 0.113 m 2 K / W in this embodiment, I a / f cl is the ratio of the air layer thermal resistance to the clothing area coefficient, which is 0.1 m 2 K / W in this embodiment.

[0163] In the process of switching the power of the intelligent frequency converter, different inertias converted according to different human comfort degrees are used for power ramp rate inertia control, and the actual given power P ref of the frequency converter is calculated according to the following formula:

[0164] P ref = GP ref0

[0165] In the formula, G is the frequency converter power ramp rate, and P ref0 is the initial given power of the frequency converter.

[0166] The power ramp rate G of the frequency converter is calculated according to the following formula:

[0167]

[0168] In the formula, k is a proportional coefficient, I PMV is the inertia of environmental information (representing the inertia of human comfort in this embodiment), and s is the Laplace operator.

[0169] According to the operating characteristics of the same type of frequency converter on the market, the original operation P ref -f characteristic curve of the intelligent frequency converter is obtained in an aggregated manner. ref -f characteristic equation considering the power ramp rate inertia control can be obtained, and the P ref -f characteristic equation considering the power ramp rate inertia control can be obtained, and the P ref

[0170] f ref = 50 ± k p P ref = 50 ± k p GP refo

[0171] In the formula, k p is the power coefficient, and P ref is the actual given power of the frequency converter.

[0172] Figure 2 In the formula, the virtual inertia unit in the control module is used to realize the calculation of the dynamic power control of the virtual inertia feedforward, and to generate the frequency correction error Δf;

[0173] Specifically, the virtual inertia unit is based on the alternating current frequency f g input by the external power grid. First, through logical judgment, it is judged whether the frequency fluctuation value (the difference between the real-time frequency of alternating current and the historical frequency of alternating current) exceeds the set frequency fluctuation threshold value, and whether the rotational inertia (virtual inertia) of the virtual synchronous motor needs to be introduced or not. When the frequency fluctuation value exceeds the frequency fluctuation threshold value, the rotational inertia of the virtual synchronous motor is introduced to calculate the frequency correction error based on the real-time frequency of alternating current. Otherwise, the rotational inertia of the virtual synchronous motor is not introduced, that is, the frequency correction error Δf is 0.

[0174] Figure 2 In the formula, the control given frequency unit in the control module is used to add the frequency correction error Δf to the frequency converter power ramp rate given frequency f ref to obtain the control given frequency f:

[0175] f = f ref + Δf.

[0176] ​Figure 2 In the control module, the control voltage unit is controlled based on the control given frequency, and the control voltage is calculated by using the voltage frequency conversion control strategy V / f. In the process of the output frequency of the frequency converter rising from 0 Hz to the basic frequency, the output voltage (i.e. the control voltage) rises in direct proportion to the V / f line of the maximum output voltage, which is called the basic V / f line. The output voltage and the frequency are in direct proportion, and the characteristic equation of the two can be expressed as:

[0177] V M = af+b

[0178] In the formula, the parameters a and b are undetermined coefficients, which can be obtained by the aggregation method, and V M is the control voltage.

[0179] Using the characteristic equation of the output voltage and the frequency in the V / f control strategy, the corresponding voltage V ref is obtained from the given frequency f M . Figure 2 In the formula, AC / AC represents the frequency conversion module, and M is the motor load (the chilled water pump of the central air conditioner). The control voltage V M generated by the control voltage unit in the control module is sent to the frequency conversion module to perform dynamic power control and intelligent climbing operation of the frequency converter. Through the frequency conversion module, the output frequency is adjusted based on the control voltage, and the output frequency is sent to the chilled water pump of the central air conditioner.

[0180] The control module has a demand response unit, which can perform demand response according to power grid information, control the frequency conversion module to change the output frequency, and obtain and generate frequency converter state information based on the output frequency of the frequency conversion module and the bus voltage. The communication module can perform bidirectional data transmission, not only can sense information to provide external information for the control module, but also can feedback the frequency converter state information to the upper master grid, so that the upper grid can monitor the running state of the intelligent frequency converter, and realize the interactive operation of the upper grid and the intelligent frequency converter.

[0181] The above is an analysis of the working steps of the intelligent frequency converter applied to the central air conditioning scene of the station. For example, Figure 3 is an information flow diagram of a multi-scene intelligent frequency converter based on double optimization control applied to the central air conditioning scene.

[0182] The intelligent frequency converter in the figure is connected to the chilled water pump of the central air conditioner;

[0183] Specifically, the frequency conversion module is connected with the chilled water pump of the central air conditioner; the communication module in the intelligent frequency converter obtains the station passenger flow, weather, station time and vehicle delay information from the station central control system through the communication bus, obtains the temperature of the central air conditioning terminal equipment, the load increase / decrease working condition of the central air conditioner compressor, the water inlet temperature of the central air conditioner condenser, and the return water temperature of the central air conditioner condenser from the station central control system or directly from the central air conditioner through the communication bus, and obtains the regulation and control information of the upper main network through the communication bus.

[0184] The above information is transmitted to the control module through the communication module; the control module generates a control voltage and sends it to the frequency conversion module; the frequency conversion module converts the power frequency alternating current into a frequency that can be used by the chilled water pump of the central air conditioner.

[0185] The embodiment aims at the problems of low running efficiency, high energy consumption and long-term operation of the central air conditioner cooling water and chilled water system, and can realize energy saving and consumption reduction of the central air conditioner by installing the intelligent frequency converter in the chilled water pump and the cooling water pump. The intelligent frequency converter designed in the application can realize the interactive response of the central air conditioner and the power grid. As a power electronic device for pump load control, the intelligent frequency converter can adaptively and intelligently control according to real-time parameters of the load, realize real-time frequency conversion and speed regulation, and realize interactive operation of high-energy-consumption load and the power grid.

[0186] Embodiment 3:

[0187] The embodiment introduces the application of a multi-scene intelligent frequency converter based on double optimization control, and the intelligent frequency converter in the embodiment is applied to a water supply system scene. The regional central control system in the scene is a municipal water supply regional central control system, the regulation and control information of the upper main network is the municipal water supply system regulation and control information, and the load is the water pump unit of the water supply system.

[0188] The working steps of the intelligent frequency converter designed in the application applied to the water supply system scene are similar to the working steps of the intelligent frequency converter applied to the station central air conditioner scene, so the intelligent control strategy process of the intelligent frequency converter will not be explained in detail.

[0189] The communication module obtains environmental information such as energy use information, passenger flow and water consumption from the municipal water supply regional central control system, and obtains main network regulation and control information or station area light storage and charging regulation and control information from the upper main network. The communication module realizes external information sensing of the intelligent frequency converter, and sends the obtained information to the control module.

[0190] Among them, the influence of environmental information on the central air conditioner power is:

[0191] The energy consumption information is the energy consumption information of other energy (such as electric energy, etc.). Generally, the energy consumption of other energy is positively correlated with the water supply amount, and when the energy consumption of other energy is large, the water supply amount needs to be increased.

[0192] The passenger flow is positively correlated with the water supply amount, and when the passenger flow is large, the water supply amount needs to be increased.

[0193] The water consumption is positively correlated with the water supply amount, and when the water consumption is large, the water supply amount needs to be increased.

[0194] It should be noted that, unlike the central air conditioning scene, the water supply system scene does not use the comfort PMV to calculate the inertia, but only needs to combine the energy consumption information, passenger flow, water consumption and other environmental information to directly convert into the corresponding water supply system inertia.

[0195] In addition to the calculation of the water supply system inertia, the working steps of the intelligent frequency converter applied to the water supply system scene are the same as those applied to the central air conditioning scene. Figure 4 An information flow schematic diagram of a multi-scene intelligent frequency converter based on double optimization control applied to a water supply system scene.

[0196] The frequency converter is connected with the water pump unit of the water supply system; specifically, the frequency conversion module is connected with the water pump unit of the water supply system;

[0197] The communication module in the frequency converter obtains the master network regulation and control information or the station area light storage and charging regulation and control information from the upper master network; the flow is obtained from the water pump unit of the water supply system, the water level is obtained from the water storage tank of the water supply system, the pipe network pressure is obtained from the pressure sensor of the water supply system, the energy consumption information, passenger flow and water consumption are obtained from the user of the water supply system (the flow, water level, pipe network pressure, energy consumption information, passenger flow and water consumption can also be obtained from the municipal water supply area control system).

[0198] The above information is transmitted to the control module through the communication module; the control module generates a control voltage and sends it to the frequency conversion module; the frequency conversion module converts the power frequency alternating current into a frequency that can be used for the water pump unit of the water supply system.

[0199] In the daily operation of the municipal water supply system, in order to ensure that the user end water supply pressure reaches the standard value, constant pressure water supply is often used to ensure the pressure at the maximum flow water peak. In the non-peak water consumption state, with the decrease of flow, the pressure of the water supply pipe network begins to rise gradually, away from the standard value, causing the phenomenon of overpressure water supply of the pipe network in the non-peak water consumption. The intelligent frequency converter is installed at the water pump of the water supply system, which detects the energy consumption related information such as user water consumption, water room passenger flow and water pipe pressure, realizes the optimization control of the water supply pressure of the water supply system, activates the adjustable capacity of the water pump, realizes the demand response of the load and realizes the interactive operation with the power grid, and achieves the intelligent regulation and control of the water supply pressure of the water supply system.

[0200] Embodiment 4:

[0201] Based on the same inventive concept, the application also provides a use method of a multi-scene intelligent frequency converter based on double optimization control, as shown in the following formula (I): Figure 5 The use method comprises the following steps:

[0202] Step 1: obtaining environment information corresponding to a current scene and an external power grid input frequency through a communication module;

[0203] Step 2: generating a control voltage by a control module based on the power grid input frequency and the environment information, using an embedded intelligent energy utilization control strategy;

[0204] Step 3: adjusting an output frequency based on the control voltage by a frequency conversion module, and sending the output frequency to each load under the scene;

[0205] The intelligent energy utilization control strategy determines a frequency correction error by introducing a rotational inertia of a virtual synchronous motor based on the power grid input frequency, and calculates a frequency given by a frequency converter power ramp rate based on the environment information;

[0206] The control voltage is generated based on the frequency correction error and the frequency given by the frequency converter power ramp rate, and is used to adjust the output frequency of the intelligent frequency converter by dynamically controlling the power of the intelligent frequency converter and controlling the power ramp rate;

[0207] The intelligent frequency converter is the multi-scene intelligent frequency converter based on double optimization control.

[0208] Preferably, the step of generating the control voltage by the control module based on the power grid input frequency and the environment information, using the embedded intelligent energy utilization control strategy, comprises the following steps:

[0209] Judging whether to introduce a virtual inertia and determining a frequency correction error by a virtual inertia unit based on the external power grid input frequency and a set threshold value;

[0210] Calculating a frequency given by a frequency converter power ramp rate based on the environment information by a power ramp rate unit using a power frequency conversion control strategy;

[0211] Adding the frequency correction error and the frequency given by the frequency converter power ramp rate by a control given frequency unit to obtain a control given frequency;

[0212] Calculating a control voltage based on the control given frequency by a control voltage unit using a voltage frequency conversion control strategy;

[0213] The power grid input frequency includes the AC power frequency input from the power grid; the environmental information includes one or more of the following in the scenario: load information, load characteristics, energy consumption information, weather conditions, date, and pedestrian traffic.

[0214] Preferably, the step of determining whether to introduce virtual inertia and determining the frequency correction error based on the external power grid input frequency and a set threshold includes:

[0215] The frequency fluctuation value is determined based on the real-time frequency and historical frequency of the AC power input from the external power grid.

[0216] The frequency fluctuation value is compared with the set frequency fluctuation threshold to determine whether the rotational inertia of the virtual synchronous motor is introduced.

[0217] If the frequency fluctuation value exceeds the frequency fluctuation threshold, the frequency correction error is calculated based on the real-time AC frequency by introducing the rotational inertia of the virtual synchronous motor; otherwise, the rotational inertia of the virtual synchronous motor is not introduced, and the frequency correction error is the set value.

[0218] Preferably, the frequency correction error is calculated using the following formula:

[0219]

[0220] In the formula, Δf is the frequency correction error, and Δω is the angular frequency difference.

[0221] The angular frequency difference Δω is calculated using the following formula:

[0222]

[0223] In the formula, J is the moment of inertia of the introduced virtual synchronous motor, J0 is the initial value of the moment of inertia of the virtual synchronous motor, and k a ω is the coefficient of angular frequency variation.

[0224] Preferably, the step of calculating the inverter power ramp-up rate given frequency based on the environmental information using a power frequency conversion control strategy includes:

[0225] By inputting environmental information as inertia into the formula for calculating the ramp rate, the power ramp rate of the frequency converter is obtained.

[0226] Input the inverter power ramp rate into the formula for calculating the inverter's given power to obtain the actual given power of the inverter.

[0227] Based on the actual given power of the inverter, the power ramp-up rate given frequency of the inverter is calculated using a power frequency conversion control strategy.

[0228] Preferably, the power ramp rate of the frequency converter is given by the following formula:

[0229] f ref = x1 ± k p P ref

[0230] wherein f ref is a given frequency of the power ramp rate of the frequency converter, x1 is a first calculation coefficient, k p is a power coefficient, P ref is an actual given power of the frequency converter;

[0231] wherein the actual given power P ref of the frequency converter is calculated according to the following equation:

[0232] P ref = GP ref0

[0233] wherein G is a power ramp rate of the frequency converter, P ref0 is an initial given power of the frequency converter;

[0234] the power ramp rate G of the frequency converter is calculated according to the following equation:

[0235]

[0236] wherein k is a proportional coefficient, x2 is a second calculation coefficient, I PMV is an inertia of the environmental information, and s is a Laplace operator.

[0237] Preferably, the method further comprises:

[0238] obtaining, by the communication module, the regulation information of the upper master grid of each load in the scene;

[0239] controlling, by the control module, the frequency converter to change the output frequency based on the regulation information;

[0240] obtaining, by the control module, the frequency converter state information based on the output frequency of the frequency converter and the bus voltage;

[0241] sending, by the communication module, the frequency converter state information to the upper master grid.

[0242] The application obtains environment information from the outside through a communication module; a control module embedded with intelligent energy utilization control strategy is used to perform dynamic power control on the frequency converter based on external power grid input frequency and to perform power ramp rate control on the frequency converter based on the environment information, so as to adjust the output frequency of the frequency converter, which helps to realize the interaction between the frequency converter and the load and the regional control center system, and changes the current situation that the frequency converter can only realize single frequency conversion by using initial parameters; the application can be applied to various scenes including central air conditioners and waterworks; through the communication module, the upper master network regulation and control information of each load in the scene can be obtained, and the control module is used to realize the demand response of the regulation and control information.

[0243] Those skilled in the art should understand that embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage, etc.) containing computer-usable program code.

[0244] The present application is described with reference to flowcharts and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as combinations of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus produce a means for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 means for performing the functions specified in one or more blocks.

[0245] These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable data processing apparatus to work in a specific manner, so that the instructions stored in the computer-readable memory produce a product including instruction means, which implements the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 one or more blocks.

[0246] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are performed on the computer or other programmable data processing apparatus to produce a computer-implemented process, so that the instructions executed on the computer or other programmable data processing apparatus provide a means for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1one or more processes and / or blocks Figure 1 the steps of a function specified in one or more blocks.

[0247] It should be noted that the above-mentioned embodiments are only used to illustrate the technical solutions of the present application, but not to limit the protection scope thereof. Although the present application has been described in detail with reference to the above-mentioned embodiments, those skilled in the art should understand that the technical personnel in the art can make various changes, modifications or equivalent replacements to the specific embodiments of the present application after reading the present application. However, these changes, modifications or equivalent replacements are all within the protection scope of the claims of the present application.

Claims

1. A multi-scenario intelligent frequency converter based on double optimization control, characterized in that, The utility model relates to a kind of intelligent energy utilization control system, including: communication module, control module and frequency conversion module;The communication module is used to obtain the environment information corresponding to current scene;The control module is used to generate control voltage based on external power grid input frequency and the environment information using embedded wisdom energy utilization control strategy;The frequency conversion module is used to adjust output frequency based on the control voltage, and the output frequency is sent to each load under the scene;The wisdom energy utilization control strategy is based on the power grid input frequency, and frequency correction error is determined by introducing the rotational inertia of virtual synchronous motor;And based on the environment information, the frequency given by power ramp rate is calculated;The frequency given by power ramp rate is calculated as follows: the control voltage is generated based on the frequency correction error and power ramp rate given frequency, for adjusting the output frequency of wisdom frequency converter by dynamic power control and power ramp rate control to wisdom frequency converter. The scene includes central air conditioner or waterworks;The environment information includes one or more of the following in the scene: load information, load characteristics, energy utilization information, weather conditions, date and passenger flow;The environment information is provided by regional central control system or load central control system in current scene. The control module includes: virtual inertia unit, power ramp rate unit, control given frequency unit and control voltage unit; The virtual inertia unit is used to judge whether to introduce virtual inertia and determine frequency correction error based on external power grid input frequency and set threshold; The power ramp rate unit is used to calculate the frequency given by power ramp rate based on the environment information using power frequency conversion control strategy; The control given frequency unit is used to add the frequency correction error and the frequency given by power ramp rate to obtain control given frequency; The control voltage unit is used to calculate control voltage based on the control given frequency using voltage frequency conversion control strategy; wherein f ref Pset is the frequency given for the power ramp rate of the frequency converter, x 1 is a first calculation coefficient, k p P is the power coefficient, P ref Pact is the actual given power of the frequency converter; Wherein the frequency converter actually given power P ref is calculated as follows: wherein G is the frequency converter power ramp rate, P ref 0 is the frequency converter initial given power; The frequency converter power ramp rate G is calculated as follows: wherein k is a proportionality factor, x 2 is a second calculation factor, I PMV is an inertia of the environmental information, s is the Laplacian operator; The power grid input frequency includes the frequency of alternating current input by power grid.

2. The intelligent frequency converter of claim 1, wherein, The virtual inertia unit is specifically used to:

3. The intelligent frequency converter of claim 1, wherein, Determine frequency fluctuation value based on real-time frequency of alternating current input by external power grid and historical frequency of alternating current; Compare the frequency fluctuation value with set frequency fluctuation threshold to judge whether to introduce the rotational inertia of virtual synchronous motor; If frequency fluctuation value exceeds frequency fluctuation threshold, calculate frequency correction error by introducing the rotational inertia of virtual synchronous motor based on real-time frequency of alternating current;Otherwise, do not introduce the rotational inertia of virtual synchronous motor, and frequency correction error is set value. The frequency correction error is calculated as follows: ω ω 4. The intelligent frequency converter of claim 3, wherein, The power ramp rate unit is specifically used to: Input environment information as inertia into the calculation formula of ramp rate to obtain the power ramp rate of frequency converter; Input the power ramp rate of frequency converter into the calculation formula of given power of frequency converter to obtain actual given power of frequency converter; Based on the actual given power of frequency converter, the frequency given by power ramp rate is calculated using power frequency conversion control strategy.

5. The intelligent frequency converter of claim 4, wherein, The control voltage is calculated as follows: where Δ f is the frequency correction error, Δ ​ is the angular frequency difference; The angular frequency difference Δ ​ is calculated as follows: wherein J J0is the introduced virtual synchronous machine moment of inertia, J 0is the initial value of the virtual synchronous machine moment of inertia, k a is the angular frequency variation coefficient.

6. The intelligent frequency converter of claim 3, wherein, ​ ​ ​ ​ 7. The intelligent frequency converter of claim 3, wherein, ​ wherein V M for controlling the voltage, a and b for setting the coefficient, f for controlling the given frequency.

8. The intelligent frequency converter of claim 1, wherein, The communication module comprises one or more communication protocols of CAN and RS-485, and supports multiple data receiving and transmitting baud rates.

9. The intelligent frequency converter of claim 1, wherein, The communication module is also used to acquire the regulation information of the upper master grid of each load in the scene, and send the frequency converter state information to the upper master grid; The control module is also used to perform demand response based on the regulation information of the upper master grid, and generate frequency converter state information; The regulation information of the upper master grid comprises power regulation information of the power master grid.

10. The intelligent frequency converter of claim 9, wherein, The control module further comprises a demand response unit. The demand response unit is specifically used to control the frequency conversion module to change the output frequency based on the regulation information of the upper master grid, and acquire and generate frequency converter state information based on the output frequency of the frequency conversion module and the bus voltage.

11. A method for using a multi-scenario intelligent frequency converter based on double optimization control, characterized in that, Comprise: Acquire the environmental information corresponding to the current scene and the external power grid input frequency through the communication module; Generate the control voltage by using the embedded intelligent energy utilization control strategy based on the power grid input frequency and the environmental information through the control module; Adjust the output frequency based on the control voltage through the frequency conversion module, and send the output frequency to each load in the scene; The intelligent energy utilization control strategy determines the frequency correction error by introducing the rotational inertia of the virtual synchronous motor based on the power grid input frequency, and calculates the frequency given by the frequency converter power climbing rate based on the environmental information; The control voltage is generated based on the frequency correction error and the power climbing rate given frequency, and is used to adjust the output frequency of the intelligent frequency converter by dynamically controlling the power of the intelligent frequency converter and controlling the power climbing rate; The intelligent frequency converter is the multi-scene intelligent frequency converter based on double optimization control according to any one of claims 1-10.

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