BP variable frequency energy-saving complete equipment and multi-load coordinated speed regulation control method thereof

Abstract

This invention provides a BP variable frequency energy-saving complete set of equipment and its multi-load coordinated speed regulation control method, belonging to the field of industrial variable frequency energy-saving control technology. The BP variable frequency energy-saving complete set of equipment includes an equipment shell, an incoming power distribution assembly, a BP pressure sensing and acquisition assembly, a coordinated main control and communication assembly, and a variable frequency drive and power frequency bypass switching assembly. The incoming power distribution assembly provides hierarchical power supply protection, energy metering, and electrical isolation for the entire equipment, while providing stable operating power for the BP pressure sensing and acquisition assembly, the coordinated main control and communication assembly, and the variable frequency drive and power frequency bypass switching assembly, outputting full-cycle energy consumption data to support quantitative calculation of energy-saving effects. Through multi-load coordinated scheduling, multi-dimensional voltage stabilization acquisition, complete set protection, and remote operation and maintenance with itemized metering, it achieves load balancing, accurate voltage stabilization, reliable operation, and quantitative energy-saving management, effectively solving the shortcomings of existing technologies and improving system energy efficiency and operation and maintenance efficiency.

Description

Technical Field

[0001] This invention relates to the field of industrial frequency conversion energy-saving control technology, specifically to a BP frequency conversion energy-saving complete set of equipment and its multi-load coordinated speed regulation control method. Background Technology

[0002] In fluid transport systems such as industrial water supply, HVAC circulation, and cooling tower ventilation, pumps and fans account for a very high proportion of energy consumption. Traditionally, flow and pressure are regulated using constant-speed drives at industrial frequency combined with throttling via pipeline valves. A significant amount of electrical energy is dissipated at the valves as throttling losses, resulting in low overall operating efficiency and serious energy waste. With the widespread adoption of variable frequency drive (VFD) technology, single VFDs are increasingly used in fluid systems. By adjusting the motor speed to match actual operating conditions, a certain degree of energy saving has been achieved. However, in complex scenarios involving multiple loads operating in parallel, several shortcomings remain. Firstly, most existing frequency converters operate in a single-unit independent control mode, lacking the ability to coordinate and schedule multiple units globally. When multiple loads are connected in parallel, uneven load distribution is likely to occur, with some units operating at full load and overload for extended periods, while others operate at light load and inefficiently for extended periods. This not only fails to fully leverage the energy-saving advantages of frequency converters but also exacerbates equipment wear and shortens service life. Furthermore, the process of adding or removing units can easily generate pressure shocks, making it difficult to guarantee the accuracy of pipeline pressure stabilization.

[0003] Secondly, the pressure closed-loop acquisition link is susceptible to interference from factors such as frequency converter harmonics and motor vibration in the field. The BP (pressure closed-loop) control is not stable enough and is prone to problems such as overshoot and oscillation, which cause pipeline pressure fluctuations to exceed the allowable range of the process. At the same time, the operating condition acquisition dimension is single, and relying solely on pressure signals cannot achieve comprehensive equipment protection and operation optimization.

[0004] Third, the existing complete sets of equipment lack integration, with strong and weak current circuits mixed together, resulting in prominent electromagnetic interference problems and limited operational reliability; moreover, most of them lack a sound fault bypass switching mechanism, and a single frequency converter failure can easily lead to the shutdown of the entire system, which cannot meet the process requirements of continuous production.

[0005] Fourth, there is a lack of unified methods for measuring electricity and quantifying energy-saving effects, making it impossible to intuitively calculate the energy-saving benefits of complete sets of equipment; at the same time, the remote operation and maintenance capabilities are weak, making it difficult to achieve fault early warning and remote parameter adjustment, resulting in high operation and maintenance costs. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a BP frequency converter energy-saving complete set of equipment and its multi-load coordinated speed regulation control method, which solves the problems of poor coordinated scheduling, easy voltage oscillation, low integration and poor reliability of existing frequency converter equipment, as well as the inability to quantify energy-saving benefits, insufficient remote operation and maintenance capabilities, and prominent defects in comprehensive use.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a BP frequency converter energy-saving complete set of equipment, comprising an equipment housing, an incoming power distribution assembly, a BP pressure sensing and acquisition assembly, a collaborative main control and communication assembly, and a frequency converter drive and power frequency bypass switching assembly. The incoming power distribution assembly is used to provide hierarchical power supply protection, energy metering and electrical isolation for the entire set of equipment. At the same time, it provides a stable working power supply for the BP pressure sensing and acquisition assembly, the collaborative main control and communication assembly, the frequency conversion drive and the power frequency bypass switching assembly, and outputs full-cycle energy consumption data to support the quantitative calculation of energy-saving effect. The BP pressure sensing and acquisition assembly is used to collect multi-dimensional operating data such as pipeline pressure, motor winding temperature and pipeline flow in real time. After isolating, filtering and anti-interference preprocessing of the collected analog signals, it is stably transmitted to the collaborative main control and communication assembly, providing accurate feedback basis for pressure closed-loop speed regulation. The collaborative main control and communication assembly is used to receive the pre-processed operating condition data uploaded by the BP pressure sensing and acquisition assembly, execute the BP pressure closed-loop calculation and multi-load load allocation logic, generate the speed control command of the corresponding branch and send it to the frequency converter drive and power frequency bypass switching assembly, and at the same time collect the operating status data to complete the closed-loop correction. The variable frequency drive and power frequency bypass switching assembly is used to receive control commands from the collaborative main control and communication assembly, drive multiple end load motors to run with stepless speed regulation, transmit operating parameters in real time, and automatically switch to power frequency bypass in the case of variable frequency branch failure to ensure continuous system operation. Among them, the signal output terminal of the BP pressure sensing and acquisition assembly is electrically connected to the analog input terminal of the collaborative main control and communication assembly, the communication port of the collaborative main control and communication assembly is bidirectionally connected to the communication port of the frequency converter drive and power frequency bypass switching assembly, and the output bus of the incoming power distribution assembly provides power supply circuits for the other assemblies. The four together constitute a complete pressure closed-loop control link of "acquisition-preprocessing-computation-drive-feedback".

[0008] Preferably, the incoming power distribution assembly includes a main molded case circuit breaker, a surge protector, a three-phase current transformer, a main busbar, a multi-function power meter, and a neutral / ground busbar; The main molded case circuit breaker is connected in series in the incoming main circuit for rapid disconnection protection against short circuits and overload faults on the incoming side. The surge protector is connected in parallel to both ends of the incoming bus to suppress power grid lightning strikes and operational surge impacts; The three-phase current transformer is installed in the three-phase main circuit and connected to a multi-functional power meter. The multi-functional power meter is used to collect the operating voltage, current, active power, and cumulative energy of the entire unit in real time, calculate and output quantitative data of energy saving, and its cumulative energy metering formula is:

[0009] In the formula, For statistical period The total power consumption of the entire machine. U(t) represents the instantaneous active power, and U(t) represents the effective value of the instantaneous line voltage. This is the effective value of the instantaneous line current. This is the instantaneous power factor.

[0010] Preferably, the variable frequency drive and power frequency bypass switching assembly is provided with an independent control branch for each end load. Each branch includes a branch circuit breaker, a dedicated variable frequency drive for fans and pumps, an output AC reactor, a variable frequency input contactor, a variable frequency output contactor, a power frequency bypass contactor, a mechanical interlocking linkage, and a thermal overload relay. The branch circuit breaker is connected in series upstream of the branch and is used for independent isolation and maintenance of single-circuit faults. The output AC reactor is connected in series on the output side of the frequency converter to suppress harmonic output and extend the insulation life of the motor; The frequency converter output contactor and the power frequency bypass contactor are installed side by side, with an external mechanical interlocking link between them. At the same time, the normally closed auxiliary contacts of both are connected in series to the power supply circuit of the other coil, forming a mechanical and electrical dual interlocking protection unit. The thermal overload relay is connected in series in the load output circuit for motor overload and overheat protection; The communication ports of each branch inverter are connected in parallel to the RS485 communication bus to receive frequency commands issued by the main control and communication assembly, and independently adjust the operating speed of the corresponding load motor.

[0011] Preferably, the BP pressure sensing and acquisition assembly includes a diffused silicon pressure transmitter, a PT100 temperature sensor for motor windings, a pipeline flow sensor, and an analog signal isolation module. The diffused silicon pressure transmitter is installed at the pressure stabilization point of the pipeline main and outputs a 4-20mA standard analog pressure signal. The analog signal isolation module provides electrical isolation and moving average filtering and shaping for pressure, temperature and flow signals. The signal transmission process uses a double-core shielded cable with single-end grounding to eliminate frequency converter harmonics and on-site electromagnetic interference. The formula for calculating the actual pressure value of the filtered pipeline network is as follows:

[0012] In the formula, For the first The filtered effective pressure value after the second sampling. This represents the number of samples taken by the sliding window, ranging from 5 to 20. For the first The original pressure sample value.

[0013] Preferably, the collaborative main control and communication assembly includes a PLC main control host, a digital I / O expansion module, an analog input module, an RS485 communication module, an industrial touch screen HMI, an intermediate relay module, and a 5G communication gateway. The PLC main control host has a built-in BP closed-loop PID calculation unit and a multi-load collaborative control unit, which is the core of the entire equipment's operation. The RS485 communication module is based on the Modbus-RTU protocol to achieve bidirectional high-speed data interaction with multiple frequency converters, transmitting frequency commands and operating status data; The industrial touch screen HMI is embedded in the cabinet door and is used to set target pressure, view real-time operating parameters, query fault records, and switch between manual and automatic operation modes. The 5G communication gateway is used to upload operational data to the cloud-based operation and maintenance platform to enable remote monitoring, parameter debugging, and proactive fault push. The intermediate relay module is connected in series between the digital output terminal and the actuator to drive the contactor coil and the audible and visual alarm device, thereby achieving power amplification and electrical isolation of the electrical signal.

[0014] A multi-load coordinated speed regulation control method for BP variable frequency energy-saving complete equipment includes the following steps: S1. Multi-dimensional operating condition data acquisition and preprocessing: The BP pressure sensing acquisition assembly collects raw data of pipeline pressure, winding temperature of each motor and pipeline flow in real time. After isolation and filtering, stable operating condition parameters are obtained and uploaded to the collaborative main control and communication assembly. S2, BP Pressure Closed-Loop Calculation: The main control and communication assembly work together to calculate the manually set target pressure. Compared with the actual pressure after filtering The pressure deviation is obtained by subtraction. Through incremental The algorithm outputs the total demand frequency of the system. ; S3, Multi-load Cooperative Allocation: The cooperative main control and communication assembly allocate loads based on the number of currently operational load units. By combining the rated power and efficiency correction coefficient of each load, the target operating frequency of each load is calculated, and independent speed control commands for each branch are generated. S4. Speed ​​regulation execution and status feedback: The variable frequency drive and power frequency bypass switching assembly receives the speed regulation command, and each variable frequency drive synchronously adjusts the speed of the corresponding load motor. At the same time, it transmits the real-time operating frequency, output current and active power data back to the collaborative main control and communication assembly through the communication bus. S5. Dynamic Correction and Protection Interlock: The main control and communication assembly continuously correct speed control commands based on the returned operating data and pressure feedback. When a single branch frequency converter fault is detected, it automatically triggers the power frequency bypass switching and adjusts the output ratio of the remaining operating loads to maintain stable pipeline pressure. Preferably, in step S2, the BP pressure closed loop uses an incremental PID algorithm to output the total demand frequency, avoiding integral accumulation deviation and improving voltage regulation stability. The calculation formula is as follows:

[0015]

[0016] In the formula, For the first Frequency adjustment increment for each sample For the first Pressure deviation value of the second sample This is the proportional adjustment coefficient. This is the integral adjustment coefficient. The differential adjustment coefficient is... For the first The total system demand frequency after this operation, and the output frequency are limited to [the specified value]. Within the range.

[0017] Preferably, in step S3, the multi-load collaborative allocation adopts a weighted equal load sharing strategy, combined with the rated power of a single load for output correction, to ensure that the operating efficiency of each load is in the optimal range. The formula for calculating the target frequency of a single load is:

[0018] In the formula, For the first Taiwan load The target operating frequency for this operation For the first Rated power of the load, This represents the total number of units currently in operation. For the first The efficiency correction factor for the load ranges from 0.95 to 1.05 and is used to correct for individual characteristic differences between the motor and the pump body.

[0019] Preferably, step S5 further includes automatic addition / reduction of generator unit rotation logic: When the total system demand frequency Continuously above the upper frequency threshold And the duration exceeds the set delay. When the time comes, the next standby load will be soft-started according to the preset rotation sequence, and smoothly integrated into the coordinated speed control circuit; When the total system demand frequency Continuously below the lower frequency threshold And the duration exceeds the set delay. When necessary, one operating load is softly stopped in a preset sequence, and the minimum number of operating units are kept to maintain the stability of the pipeline pressure. During the process of adding or removing units, a frequency ramp transition is adopted, and the transition time is not less than 10 seconds to avoid sudden pressure shocks in the pipeline.

[0020] Preferably, in step S5, when a fault is detected in a single frequency converter, the corresponding frequency converter branch contactor is immediately disconnected, and the power frequency bypass contactor is closed to complete a seamless switching; simultaneously, the target frequency of the remaining operating load is automatically increased according to the rated output ratio of the faulty unit to compensate for the missing output and maintain stable pipeline pressure. The fault pressure compensation correction formula is:

[0021] In the formula, The remaining number after the fault occurred The target frequency for the load adjustment of the platform. The rated power of the faulty load; when the operating frequency of a single load is continuously lower than the sleep threshold and the pipeline pressure is higher than the set upper limit under low load conditions at night, the system enters a sleep shutdown state. After the pipeline pressure drops to the wake-up threshold, the load will automatically restart and resume stable operation.

[0022] This invention provides a BP frequency converter energy-saving complete set of equipment and its multi-load coordinated speed regulation control method. It has the following beneficial effects: 1. This invention achieves balanced output matching and smooth, shock-free voltage regulation of multiple units through a multi-load weighted and distributed collaborative scheduling architecture, combined with automatic addition and removal of units, ramp transition and timed rotation logic. It effectively solves the problems of uneven load distribution and uneven equipment wear in traditional solutions, fully releases the energy-saving potential of frequency conversion, and extends the service life of the entire set of equipment.

[0023] 2. This invention achieves high-interference, high-precision pipeline pressure stabilization control by using a multi-dimensional operating condition acquisition architecture of pressure, temperature, and flow rate, combined with analog signal isolation filtering and incremental closed-loop adjustment algorithm. It eliminates overshoot oscillation caused by frequency converter harmonic interference and provides sufficient data support for the all-dimensional operation protection of equipment.

[0024] 3. This invention achieves a highly reliable continuous operation protection effect through an integrated cabinet structure with physical separation of strong and weak currents, combined with independent branch drive and a dual mechanical and electrical interlocking power frequency bypass mechanism. It effectively solves the drawbacks of traditional equipment such as strong electromagnetic interference and shutdown due to a single fault, and allows for seamless switching of single branch faults, meeting the process requirements of continuous production.

[0025] 4. This invention, through a full-cycle segmented energy metering and acquisition architecture, and in conjunction with a 5G communication gateway and cloud-based operation and maintenance platform, achieves quantifiable energy-saving benefits and remote operation and maintenance management. It can intuitively calculate energy-saving data, and supports remote parameter debugging and proactive fault push, significantly reducing on-site operation and maintenance manpower costs. Attached Figure Description

[0026] Figure 1 This is a perspective view of the device of the present invention; Figure 2 This is a cross-sectional view of the device of the present invention; Figure 3 This is a modular framework diagram of the present invention; Figure 4 This is a flowchart of the steps of the present invention.

[0027] The components include: 1. Equipment housing; 2. Incoming power distribution assembly; 3. BP pressure sensing and acquisition assembly; 4. Collaborative main control and communication assembly; and 5. Variable frequency drive and power frequency bypass switching assembly. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1:

[0030] like Figure 1-4 As shown, this embodiment of the invention provides a BP frequency converter energy-saving complete set of equipment, including an equipment housing 1, an incoming power distribution assembly 2, a BP pressure sensing and acquisition assembly 3, a collaborative main control and communication assembly 4, and a frequency converter drive and power frequency bypass switching assembly 5. The incoming power distribution assembly 2 is used to provide hierarchical power supply protection, energy metering and electrical isolation for the entire set of equipment, and at the same time provide a stable working power supply for the BP pressure sensing and acquisition assembly 3, the collaborative main control and communication assembly 4, the frequency converter drive and power frequency bypass switching assembly 5, and output full-cycle energy consumption data to support the quantitative calculation of energy-saving effect. The incoming power distribution assembly 2 includes... The system includes a main molded case circuit breaker, surge protector, three-phase current transformer, main busbar, multi-function power meter, and neutral / ground busbar. The main molded case circuit breaker is connected in series in the incoming main circuit for rapid disconnection protection against short circuits and overload faults on the incoming side. The surge protector is connected in parallel across the incoming busbar to suppress lightning strikes and operational surges. The three-phase current transformer is installed in the three-phase main circuit and connected to the multi-function power meter. The multi-function power meter is used to collect real-time operating voltage, current, active power, and cumulative energy of the entire unit, calculate and output quantitative data on energy savings, and its cumulative energy metering formula is: In the formula, For statistical period The total power consumption of the entire machine. U(t) represents the instantaneous active power, and U(t) represents the effective value of the instantaneous line voltage. This is the effective value of the instantaneous line current. The instantaneous power factor; Specifically: This embodiment is a BP frequency conversion energy-saving complete set of equipment applied to industrial water supply scenarios. It is integrated into the equipment shell 1. The cabinet is divided into two independent compartments, a power chamber and a control chamber, by a vertical metal partition. The incoming power distribution assembly 2 and the frequency conversion drive and power frequency bypass switching assembly 5 are arranged on the power chamber side. The cabinet terminals and conditioning components of the BP pressure sensing and acquisition assembly 3, as well as the collaborative main control and communication assembly 4, are arranged on the control chamber side. Strong and weak currents are physically separated to reduce electromagnetic interference. The incoming power distribution assembly 2 provides hierarchical power supply protection, power metering and electrical isolation for the entire set of equipment. It is equipped with a main molded case circuit breaker, surge protector, three-phase current transformer, main bus copper bus, multi-functional power meter and neutral ground bus. The main molded case circuit breaker is connected in series with the incoming main circuit, which can quickly disconnect and isolate when a short circuit or overload fault occurs on the incoming side. The surge protector is connected in parallel at both ends of the incoming bus to suppress the impact of power grid lightning strikes and operation surges. The three-phase current transformer is installed in the three-phase main circuit and connected to the multi-functional power meter. The multi-functional power meter collects parameters such as the operating voltage, current, and active power of the whole machine in real time, calculates the cumulative power consumption and energy saving, and provides data support for the quantitative evaluation of energy saving effect. The output bus of the incoming power distribution assembly 2 provides stable operating power to the other three assemblies. The BP pressure sensing and acquisition assembly 3 is responsible for collecting multi-dimensional operating condition data such as pipeline pressure, motor winding temperature and pipeline flow in real time. After isolating, filtering and anti-interference preprocessing of the collected analog signals, it is stably transmitted to the collaborative main control and communication assembly 4, providing accurate feedback for pressure closed-loop speed regulation. The assembly includes a diffused silicon pressure transmitter, a PT100 temperature sensor for motor windings, a pipeline flow sensor, and an analog signal isolation module. The diffused silicon pressure transmitter is installed at the pressure stabilization point of the pipeline main and outputs a 4-20mA standard analog pressure signal. The analog signal isolation module performs electrical isolation and moving average filtering and shaping on pressure, temperature, and flow signals one by one. The signal transmission uses double-core shielded cables with single-end grounding throughout, effectively eliminating frequency converter harmonics and on-site electromagnetic interference, and outputting stable operating condition feedback signals. The collaborative main control and communication assembly 4 serves as the core of the entire system's operation. It receives pre-processed operating condition data uploaded by the BP pressure sensing and acquisition assembly 3, executes BP pressure closed-loop calculations and multi-load distribution logic, generates speed control commands for the corresponding branches, and sends them to the frequency converter drive and power frequency bypass switching assembly 5. Simultaneously, it collects operating status data to complete closed-loop correction. This assembly is equipped with a PLC main control unit, digital I / O expansion modules, analog input modules, an RS485 communication module, an industrial touchscreen HMI, intermediate relay modules, and a 5G communication gateway. The PLC main control unit integrates a BP closed-loop calculation unit and a multi-load collaborative control unit. The RS485 communication module, based on the Modbus-RTU protocol, enables bidirectional high-speed data interaction with multiple frequency converters, transmitting frequency commands and operating status data. An industrial touchscreen HMI is embedded in the cabinet door and used to set target pressure, view real-time operating parameters, query fault records, and switch between manual and automatic operation modes. A 5G communication gateway is used to upload operating data to the cloud-based operation and maintenance platform to achieve remote monitoring, parameter debugging, and proactive fault push. An intermediate relay module is connected in series between the digital output terminal and the actuator to drive the contactor coil and the audible and visual alarm device, realizing power amplification and electrical isolation of electrical signals. The frequency converter drive and power frequency bypass switching assembly 5 receives control commands from the main control and communication assembly 4 to drive multiple end load motors to operate with stepless speed regulation, transmit operating parameters in real time, and automatically switch to the power frequency bypass in the case of a fault in the frequency converter branch to ensure continuous system operation. Each assembly has an independent control branch for each end load. Each branch includes a branch circuit breaker, a dedicated frequency converter for fans and pumps, an output AC reactor, a frequency converter input contactor, a frequency converter output contactor, a power frequency bypass contactor, a mechanical interlocking linkage, and a thermal overload relay. The branch circuit breaker is connected in series upstream of the branch for independent isolation and maintenance of single-circuit faults. The output AC reactor is connected in series on the output side of the frequency converter to suppress harmonic output and extend the insulation life of the motor. The frequency converter output contactor and the power frequency bypass contactor are installed side by side, with an external mechanical interlocking linkage between them. At the same time, the normally closed auxiliary contacts of both are connected in series to the power supply circuit of the other's coil, forming a mechanical and electrical dual interlocking protection unit. The thermal overload relay is connected in series in the load output circuit for motor overload and overheat protection. The communication ports of each branch frequency converter are connected in parallel to the RS485 communication bus to receive frequency commands issued by the collaborative main control and communication assembly 4, and independently adjust the operating speed of the corresponding load motor. The signal output terminal of the BP pressure sensing and acquisition assembly 3 is electrically connected to the analog input terminal of the collaborative main control and communication assembly 4. The communication port of the collaborative main control and communication assembly 4 is bidirectionally connected to the communication port of the frequency converter drive and power frequency bypass switching assembly 5. The four together form a complete pressure closed-loop control link of "acquisition-preprocessing-calculation-drive-feedback".

[0031] The BP pressure sensing and acquisition assembly 3 is used to collect multi-dimensional operating data such as pipeline pressure, motor winding temperature, and pipeline flow in real time. After isolating, filtering, and anti-interference preprocessing of the collected analog signals, the data is stably transmitted to the collaborative main control and communication assembly 4, providing accurate feedback for pressure closed-loop speed regulation. The BP pressure sensing and acquisition assembly 3 includes a diffused silicon pressure transmitter, a PT100 temperature sensor for the motor winding, a pipeline flow sensor, and an analog signal isolation module. The diffused silicon pressure transmitter is installed at the pressure stabilization point of the pipeline main and outputs a 4-20mA standard analog pressure signal. The analog signal isolation module performs electrical isolation and moving average filtering and shaping on the pressure, temperature, and flow signals. The signal transmission uses a double-core shielded cable with single-end grounding to eliminate frequency converter harmonics and on-site electromagnetic interference. The formula for calculating the actual pipeline pressure value after filtering is as follows: In the formula, For the first The filtered effective pressure value after the second sampling. This represents the number of samples taken by the sliding window, ranging from 5 to 20. For the first The original pressure sampling value of the first time; Specifically: the collaborative main control and communication assembly 4 is used to receive preprocessed operating condition data uploaded by the BP pressure sensing and acquisition assembly 3, execute BP pressure closed-loop calculation and multi-load load allocation logic, generate speed control commands for the corresponding branches and send them to the frequency converter drive and power frequency bypass switching assembly 5, and simultaneously collect operating status data to complete closed-loop correction. The collaborative main control and communication assembly 4 includes a PLC main control host, digital I / O expansion modules, analog input modules, RS485 communication modules, industrial touch screen HMI, intermediate relay modules and 5G communication gateway; the PLC main control host has a built-in BP closed-loop PID calculation unit and a multi-load collaborative control unit, which is the complete set. The core of the equipment's operation; the RS485 communication module, based on the Modbus-RTU protocol, enables bidirectional high-speed data interaction with multiple frequency converters, transmitting frequency commands and operating status data; the industrial touch screen HMI is embedded in the cabinet door, used to set target pressure, view real-time operating parameters, query fault records, and switch between manual and automatic operating modes; the 5G communication gateway is used to upload operating data to the cloud-based operation and maintenance platform, enabling remote monitoring, parameter debugging, and proactive fault push; the intermediate relay module is connected in series between the digital output terminal and the actuator, used to drive the contactor coil and the audible and visual alarm device, realizing power amplification and electrical isolation of electrical signals; The difference lies in the upgraded protection level of the equipment casing 1 to IP42. A temperature and humidity controller and dehumidification heating components are added next to the power distribution assembly 2 inside the cabinet. All cable entry points at the bottom of the cabinet are sealed with waterproof glands to prevent moisture intrusion and damage to components. All wiring terminals inside the BP pressure sensing and acquisition assembly 3 use three-proof sealed terminals, and the grounding resistance of the signal shielding layer is controlled within 4Ω, further improving sampling stability in complex electromagnetic environments. The collaborative main control and communication assembly 4 incorporates low-load sleep logic. When water consumption is low at night, if the operating frequency of a single unit remains below the set threshold and the pipeline pressure is above the set upper limit, the system automatically enters a sleep shutdown state. Once the pipeline pressure drops to the wake-up threshold, the unit automatically restarts to resume stable operation. The 5G communication gateway, equipped with an external high-gain antenna on the top of the cabinet, effectively avoids signal shielding issues in underground pump rooms, ensuring stable and reliable data transmission for remote maintenance.

[0032] The variable frequency drive and power frequency bypass switching assembly 5 receives control commands from the main control and communication assembly 4, drives multiple end-load motors to operate with stepless speed regulation, transmits operating parameters in real time, and automatically switches to the power frequency bypass in the event of a fault in the variable frequency branch to ensure continuous system operation. The variable frequency drive and power frequency bypass switching assembly 5 has an independent control branch for each end load. Each branch includes a branch circuit breaker, a dedicated frequency converter for fans and pumps, an output AC reactor, a frequency converter input contactor, a frequency converter output contactor, a power frequency bypass contactor, a mechanical interlocking linkage, and a thermal overload relay. The branch circuit breaker is connected in series upstream of the branch for independent isolation and maintenance of single-circuit faults. The output AC reactor is connected in series on the output side of the frequency converter to suppress harmonic output and extend the insulation life of the motor. The frequency converter output contactor and the power frequency bypass contactor are installed side-by-side, with an external connection between them. A mechanical interlocking linkage connects the normally closed auxiliary contacts of both sides into the power supply circuit of the other's coil, forming a dual mechanical and electrical interlocking protection unit; a thermal overload relay is connected in series in the load output circuit for motor overload and overheat protection; the communication ports of each branch frequency converter are connected in parallel to the RS485 communication bus to receive frequency commands issued by the collaborative main control and communication assembly 4, and independently adjust the operating speed of the corresponding load motor; among them, the signal output terminal of the BP pressure sensing and acquisition assembly 3 is electrically connected to the analog input terminal of the collaborative main control and communication assembly 4, the communication port of the collaborative main control and communication assembly 4 is bidirectionally connected to the communication port of the frequency converter drive and power frequency bypass switching assembly 5, and the output bus of the incoming power distribution assembly 2 provides power supply circuits for the other assemblies. The four together form a complete pressure closed-loop control link of "acquisition-preprocessing-calculation-drive-feedback".

[0033] Specifically, the difference lies in the fact that each branch of the frequency converter drive and power frequency bypass switching assembly 5 is equipped with a bypass status auxiliary contact feedback, the mechanical interlocking linkage is made of high-strength insulating material and is integrally stamped, and the limit stroke and the contactor's closing stroke are precisely matched to prevent interlocking failure caused by contact welding; the electrical interlocking circuit adds a two-stage normally closed contact verification link, and only when both the frequency converter and the power frequency contactor are in the open state is one of them allowed to close, completely avoiding the risk of short circuit between frequency converter and power frequency grid connection. During operation, when the PLC main control unit of the collaborative main control and communication assembly 4 detects an overcurrent, overvoltage, or overheating fault in a single branch inverter, it first issues a shutdown command to disconnect the inverter output contactor. After confirming the disconnection status through auxiliary contacts, it delays for 0.5 seconds before engaging the power frequency bypass contactor. During the switching process, the output of the remaining operating branches automatically increases to compensate for the pressure gap. The pressure fluctuation of the entire pipeline network is controlled within the allowable range of the process. The system can maintain continuous operation without manual intervention, making it fully adaptable to continuous production scenarios where water supply interruption is not allowed.

[0034] Example 2:

[0035] A multi-load coordinated speed regulation control method for BP variable frequency energy-saving complete equipment includes the following steps: S1. Multi-dimensional operating condition data acquisition and preprocessing: The BP pressure sensing acquisition assembly 3 collects the original data of pipeline pressure, winding temperature of each motor and pipeline flow in real time. After isolation and filtering, stable operating condition parameters are obtained and uploaded to the collaborative main control and communication assembly 4. S2, BP Pressure Closed-Loop Calculation: The main control and communication assembly 4 will calculate the manually set target pressure. Compared with the actual pressure after filtering The pressure deviation is obtained by subtraction. Through incremental The algorithm outputs the total demand frequency of the system. The BP pressure closed-loop uses an incremental PID algorithm to output the total demand frequency, avoiding integral accumulation deviation and improving voltage regulation stability. Its calculation formula is as follows: In the formula, For the first Frequency adjustment increment for each sample For the first Pressure deviation value of the second sample This is the proportional adjustment coefficient. This is the integral adjustment coefficient. The differential adjustment coefficient is... For the first The total system demand frequency after this operation, and the output frequency are limited to [the specified value]. Within the range; S3, Multi-load Cooperative Allocation: The cooperative main control and communication assembly 4 allocates loads based on the number of currently operational load units. Based on the rated power and efficiency correction coefficient of each load, the target operating frequency of each load is calculated, and independent speed control commands are generated for each branch. A weighted equal load sharing strategy is adopted for multi-load collaborative allocation, and output correction is performed based on the rated power of each load to ensure that the operating efficiency of each load is within the optimal range. The formula for calculating the target frequency of a single load is as follows: In the formula, For the first Taiwan load The target operating frequency for this operation For the first Rated power of the load, This represents the total number of units currently in operation. For the first The efficiency correction factor for the load is between 0.95 and 1.05, and is used to correct for individual characteristic differences between the motor and the pump body. S4. Speed ​​regulation execution and status feedback: The variable frequency drive and power frequency bypass switching assembly 5 receives the speed regulation command, and each variable frequency drive synchronously adjusts the speed of the corresponding load motor. At the same time, it transmits the real-time operating frequency, output current and active power data back to the collaborative main control and communication assembly 4 through the communication bus. S5. Dynamic Correction and Protection Interlock: The main control and communication assembly 4 continuously corrects the speed control commands based on the returned operating data and pressure feedback. When a single branch frequency converter fault is detected, it automatically triggers the power frequency bypass switching and adjusts the output ratio of the remaining operating loads to maintain stable pipeline pressure. This includes automatic addition and reduction of unit rotation logic: when the total system demand frequency... Continuously above the upper frequency threshold And the duration exceeds the set delay. When the system's total demand frequency is at a certain time, the next standby load is soft-started according to the preset rotation sequence, smoothly integrating into the coordinated speed control loop; Continuously below the lower frequency threshold And the duration exceeds the set delay. When a load is softly stopped in a preset sequence, a minimum number of operating units are maintained to stabilize the pipeline pressure. During the addition or removal of units, a frequency ramp transition is used, with a transition time of no less than 10 seconds, to avoid sudden pressure surges in the pipeline. When a fault is detected in a single frequency converter, the corresponding frequency converter branch contactor is immediately disconnected, and the power frequency bypass contactor is closed to complete a seamless switchover. Simultaneously, the target frequency of the remaining operating loads is automatically increased according to the rated output ratio of the faulty unit to compensate for the lost output and maintain stable pipeline pressure. The fault pressure compensation correction formula is: In the formula, The remaining number after the fault occurred The target frequency for the load adjustment of the platform. The rated power of the faulty load; when the operating frequency of a single load is continuously lower than the sleep threshold and the pipeline pressure is higher than the set upper limit under low load conditions at night, the system enters a sleep shutdown state. After the pipeline pressure drops to the wake-up threshold, the load will automatically restart and resume stable operation.

[0036] The specific control process is as follows: After the system is powered on and initialized, the BP pressure sensing and acquisition assembly 3 first collects the original operating condition data of the main pipeline pressure stabilization point, the winding temperature of each motor, and the pipeline flow rate in real time. After electrical isolation and sliding filter preprocessing by the analog signal isolation module in the cabinet, the stable operating condition parameters are obtained after eliminating harmonic interference on site. The parameters are then uploaded to the collaborative main control and communication assembly 4 through the analog signal channel. The collaborative main control and communication assembly 4 reads the target pressure value set by the operator through the touch screen, and calculates the difference between it and the filtered actual pipeline pressure to obtain the pressure deviation value. An incremental closed-loop adjustment algorithm is used to calculate and output the total required frequency of the system. During the calculation process, the frequency output is limited to the preset upper and lower limit range to avoid adjustment oscillation caused by integral accumulation deviation and improve the stability of pressure stabilization control. After obtaining the total required frequency of the system, the collaborative main control and communication assembly 4 calculates the target operating frequency for each load by performing a weighted average calculation based on the total number of currently operating loads and the rated power and efficiency correction coefficient of each load. This generates independent speed control commands for each branch and sends them to the frequency converter drive and power frequency bypass switching assembly 5 via the RS485 communication bus. Upon receiving the corresponding speed control command, each frequency converter in the frequency converter drive and power frequency bypass switching assembly 5 synchronously adjusts the operating speed of the corresponding load motor. Simultaneously, it transmits its real-time operating frequency, output current, active power, and other operating parameters back to the collaborative main control and communication assembly 4 via the communication bus. This, combined with pipeline pressure feedback, forms a complete closed loop, continuously and dynamically correcting the speed control commands to maintain the pipeline pressure stable near the target value.

[0037] The difference lies in the addition of comprehensive automatic unit rotation and fault interlock protection logic. During operation, the main control and communication assembly 4 monitors the changing trend of the total demand frequency in real time. When the total demand frequency is continuously higher than the set upper frequency threshold and the duration exceeds the preset unit addition delay time, the system starts the next standby load according to the preset unit rotation sequence via frequency converter soft start. The start-up process uses a smooth frequency ramp transition with a transition time of no less than 10 seconds. After the standby unit is integrated into operation, the load sharing calculation is re-executed, and multiple units share the pipeline load. Conversely, when the total demand frequency is continuously lower than the lower frequency threshold and the duration exceeds the preset unit reduction delay time, the excess operating loads are soft-stopped sequentially according to the rotation sequence, retaining the fewest operating units to maintain pipeline pressure stability and avoid equipment damage and pressure fluctuations caused by frequent unit starts and stops. When the main control and communication assembly 4 detects fault signals such as overcurrent, overvoltage, or overheating in a single branch inverter, it immediately issues a shutdown command to the corresponding branch, disconnects the inverter output contactor, and closes the power frequency bypass contactor after confirming that the branch is completely disconnected to complete the seamless switching. After the switching is completed, the system automatically increases the target operating frequency of the remaining normally operating loads in sync with the rated output ratio of the faulty unit to compensate for the lost output of the faulty unit, maintain the pipeline pressure without significant drop, and ensures stable and uninterrupted water supply under continuous production conditions without manual intervention.

[0038] The main control process is the same as in Example 1, except that a low-load sleep-wake logic and a time-sharing parameter adaptation mechanism are added. During off-peak water usage at night, the system automatically switches to a low-load operating parameter group, appropriately relaxing the pressure regulation accuracy and extending the regulation cycle to avoid frequent start-ups and shutdowns of units caused by small flow fluctuations. When the operating frequency of a single operating load is continuously lower than the set sleep threshold, and the actual pressure of the pipeline network is continuously higher than the set pressure upper limit, the main control and communication assembly 4 control system gradually reduces the output frequency until it stops and enters a sleep standby state, further reducing no-load energy consumption. During the sleep period, the BP pressure sensing and acquisition assembly 3 continues to monitor the pipeline network pressure. When the pipeline network pressure drops to the preset wake-up threshold, the system immediately soft-starts the corresponding load unit to resume pressure regulation operation. The entire process is completed automatically without manual operation. At the same time, the unit timed rotation function in this example can be automatically executed in combination with the cumulative running time to balance the operating wear of each unit and extend the service life of the entire set of equipment. With the help of the remote communication module, all operating events such as sleep, wake-up, rotation, and fault can be uploaded to the cloud platform for remote management by maintenance personnel.

[0039] Table 1: Comparison of Overall Performance of the Complete Technical Solutions

[0040] Table 2: Comparison of Relative Energy Consumption of the System under Different Load Rates

[0041] Table 3: Comparison of Pipeline Pressure Stabilization Performance under Load Change Conditions

[0042] Table 4: Comparison of System Operation Reliability and Protection Capability

[0043] Although embodiments of the invention 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 to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A BP variable frequency energy-saving complete set of equipment, comprising an equipment housing (1), an incoming power distribution assembly (2), a BP pressure sensing and acquisition assembly (3), a collaborative main control and communication assembly (4), and a variable frequency drive and power frequency bypass switching assembly (5), characterized in that: The incoming power distribution assembly (2) is used to provide graded power supply protection, power metering and electrical isolation for the whole set of equipment. At the same time, it provides stable working power for the BP pressure sensing and acquisition assembly (3), the collaborative main control and communication assembly (4), the frequency conversion drive and power frequency bypass switching assembly (5), and outputs full-cycle energy consumption data to support the quantitative calculation of energy saving effect. The BP pressure sensing and acquisition assembly (3) is used to collect multi-dimensional operating data of pipeline pressure, motor winding temperature and pipeline flow in real time. After the collected analog signals are isolated, filtered and anti-interference preprocessed, they are stably transmitted to the collaborative main control and communication assembly (4) to provide accurate feedback basis for pressure closed-loop speed regulation. The collaborative main control and communication assembly (4) is used to receive the pre-processed working condition data uploaded by the BP pressure sensing and acquisition assembly (3), execute the BP pressure closed-loop calculation and multi-load load allocation logic, generate the speed control command of the corresponding branch and send it to the frequency converter drive and power frequency bypass switching assembly (5), and at the same time collect the operating status data to complete the closed-loop correction. The variable frequency drive and power frequency bypass switching assembly (5) is used to receive control commands from the collaborative main control and communication assembly (4), drive multiple end load motors to run with stepless speed regulation, transmit operating parameters in real time, and automatically switch to power frequency bypass in the case of variable frequency branch failure to ensure continuous operation of the system. Among them, the signal output terminal of the BP pressure sensing and acquisition assembly (3) is electrically connected to the analog input terminal of the collaborative main control and communication assembly (4), the communication port of the collaborative main control and communication assembly (4) is bidirectionally connected to the communication port of the frequency converter drive and power frequency bypass switching assembly (5), and the output bus of the incoming power distribution assembly (2) provides power supply circuits for the other assemblies. The four together constitute a complete pressure closed-loop control link of "acquisition-preprocessing-computation-drive-feedback".

2. The BP frequency converter energy-saving complete set of equipment according to claim 1, characterized in that: The incoming power distribution assembly (2) includes a main molded case circuit breaker, a surge protector, a three-phase current transformer, a main busbar, a multi-function power meter, and a neutral ground busbar; The main molded case circuit breaker is connected in series in the incoming main circuit for rapid disconnection protection against short circuits and overload faults on the incoming side. The surge protector is connected in parallel to both ends of the incoming bus to suppress power grid lightning strikes and operational surge impacts; The three-phase current transformer is installed in the three-phase main circuit and connected to a multi-functional power meter. The multi-functional power meter is used to collect the operating voltage, current, active power, and cumulative energy of the entire unit in real time, calculate and output quantitative data of energy saving, and its cumulative energy metering formula is: In the formula, For statistical period The total power consumption of the entire machine. U(t) represents the instantaneous active power, and U(t) represents the effective value of the instantaneous line voltage. This is the effective value of the instantaneous line current. This is the instantaneous power factor.

3. The BP frequency converter energy-saving complete set of equipment according to claim 1, characterized in that: The variable frequency drive and power frequency bypass switching assembly (5) is configured with an independent control branch for each end load. Each branch includes a branch circuit breaker, a dedicated frequency converter for fans and pumps, an output AC reactor, a frequency converter input contactor, a frequency converter output contactor, a power frequency bypass contactor, a mechanical interlocking link and a thermal overload relay. The branch circuit breaker is connected in series upstream of the branch and is used for independent isolation and maintenance of single-circuit faults. The output AC reactor is connected in series on the output side of the frequency converter to suppress harmonic output and extend the insulation life of the motor. The frequency converter output contactor and the power frequency bypass contactor are installed side by side, with an external mechanical interlocking link between them. At the same time, the normally closed auxiliary contacts of both are connected in series to the power supply circuit of the other coil, forming a mechanical and electrical dual interlocking protection unit. The thermal overload relay is connected in series in the load output circuit for motor overload and overheat protection; The communication ports of each branch inverter are connected in parallel to the RS485 communication bus to receive frequency commands issued by the main control and communication assembly (4) and independently adjust the running speed of the corresponding load motor.

4. The BP frequency converter energy-saving complete set of equipment according to claim 1, characterized in that: The BP pressure sensing and acquisition assembly (3) includes a diffused silicon pressure transmitter, a motor winding PT100 temperature sensor, a pipeline flow sensor, and an analog signal isolation module. The diffused silicon pressure transmitter is installed at the pressure stabilization point of the pipeline main and outputs a 4-20mA standard analog pressure signal. The analog signal isolation module provides electrical isolation and moving average filtering and shaping for pressure, temperature and flow signals. The signal transmission process uses a double-core shielded cable with single-end grounding to eliminate frequency converter harmonics and on-site electromagnetic interference. The formula for calculating the actual pressure value of the filtered pipeline network is as follows: In the formula, For the first The filtered effective pressure value after the second sampling. This represents the number of samples taken by the sliding window, ranging from 5 to 20. For the first The original pressure sample value.

5. The BP frequency converter energy-saving complete set of equipment according to claim 1, characterized in that: The collaborative main control and communication assembly (4) includes a PLC main control host, a digital I / O expansion module, an analog input module, an RS485 communication module, an industrial touch screen HMI, an intermediate relay module and a 5G communication gateway. The PLC main control host has a built-in BP closed-loop PID calculation unit and a multi-load collaborative control unit, which is the core of the entire equipment's operation. The RS485 communication module is based on the Modbus-RTU protocol to achieve bidirectional high-speed data interaction with multiple frequency converters, transmitting frequency commands and operating status data; The industrial touch screen HMI is embedded in the cabinet door and is used to set target pressure, view real-time operating parameters, query fault records, and switch between manual and automatic operation modes. The 5G communication gateway is used to upload operational data to the cloud-based operation and maintenance platform to enable remote monitoring, parameter debugging, and proactive fault push. The intermediate relay module is connected in series between the digital output terminal and the actuator to drive the contactor coil and the audible and visual alarm device, thereby achieving power amplification and electrical isolation of the electrical signal.

6. A multi-load coordinated speed control method for a BP variable frequency energy-saving complete set of equipment, wherein the BP variable frequency energy-saving complete set of equipment according to any one of claims 1 to 5 is characterized in that, Includes the following steps: S1. Multi-dimensional working condition data acquisition and preprocessing: The original data of pipeline pressure, winding temperature of each motor and pipeline flow are collected in real time through the BP pressure sensing acquisition assembly (3). After isolation and filtering, stable working condition parameters are obtained and uploaded to the collaborative main control and communication assembly (4). S2, BP pressure closed-loop calculation: the main control and communication assembly (4) will calculate the manually set target pressure. Compared with the actual pressure after filtering The pressure deviation is obtained by subtraction. Through incremental The algorithm outputs the total demand frequency of the system. ; S3, Multi-load collaborative distribution: Collaborative main control and communication assembly (4) Based on the number of load units currently in operation. By combining the rated power and efficiency correction coefficient of each load, the target operating frequency of each load is calculated, and independent speed control commands for each branch are generated. S4. Speed ​​regulation execution and status feedback: The variable frequency drive and power frequency bypass switching assembly (5) receives the speed regulation command, and each frequency converter synchronously adjusts the speed of the corresponding load motor. At the same time, the real-time operating frequency, output current and active power data are fed back to the collaborative main control and communication assembly (4) through the communication bus. S5. Dynamic correction and protection interlock: The main control and communication assembly (4) continuously corrects the speed regulation command based on the returned operating data and pressure feedback. When a single branch frequency converter fault is detected, the power frequency bypass switching is automatically triggered, and the output ratio of the remaining operating loads is adjusted to maintain the stability of the pipeline pressure.

7. The multi-load coordinated speed control method for BP frequency converter energy-saving complete set of equipment according to claim 6, characterized in that: In step S2, the BP pressure closed loop uses an incremental PID algorithm to output the total demand frequency, avoiding integral accumulation deviation and improving voltage regulation stability. The calculation formula is as follows: In the formula, For the first Frequency adjustment increment for each sample For the first Pressure deviation value of the second sample This is the proportional adjustment coefficient. This is the integral adjustment coefficient. The differential adjustment coefficient is... For the first The total system demand frequency after this operation, and the output frequency are limited to [the specified value]. Within the range.

8. The multi-load coordinated speed control method for BP frequency converter energy-saving complete set of equipment according to claim 6, characterized in that: In step S3, the multi-load collaborative allocation adopts a weighted equal load sharing strategy, combined with the rated power of each load for output correction, to ensure that the operating efficiency of each load is in the optimal range. The target frequency calculation formula for a single load is as follows: In the formula, For the first Taiwan load The target operating frequency for this operation For the first Rated power of the load, This represents the total number of units currently in operation. For the first The efficiency correction factor for the load ranges from 0.95 to 1.05 and is used to correct for individual characteristic differences between the motor and the pump body.

9. A multi-load coordinated speed control method for BP frequency converter energy-saving complete set of equipment according to claim 6, characterized in that: Step S5 also includes automatic addition and reduction of generator unit rotation logic: When the total system demand frequency Continuously above the upper frequency threshold And the duration exceeds the set delay. When the time comes, the next standby load will be soft-started according to the preset rotation sequence, and smoothly integrated into the coordinated speed control circuit; When the total system demand frequency Continuously below the lower frequency threshold And the duration exceeds the set delay. When necessary, one operating load is softly stopped in a preset sequence, and the minimum number of operating units are kept to maintain the stability of the pipeline pressure. During the process of adding or removing units, a frequency ramp transition is adopted, and the transition time is not less than 10 seconds to avoid sudden pressure shocks in the pipeline.

10. A multi-load coordinated speed control method for BP frequency converter energy-saving complete set of equipment according to claim 6, characterized in that: In step S5, when a fault is detected in a single frequency converter, the corresponding frequency converter branch contactor is immediately disconnected, and the power frequency bypass contactor is closed to complete a seamless switching. Simultaneously, the target frequency of the remaining operating load is automatically increased according to the rated output ratio of the faulty unit to compensate for the lost output and maintain stable pipeline pressure. The fault pressure compensation correction formula is as follows: In the formula, The remaining number after the fault occurred The target frequency for the load adjustment of the platform. The rated power of the faulty load; when the operating frequency of a single load is continuously lower than the sleep threshold and the pipeline pressure is higher than the set upper limit under low load conditions at night, the system enters a sleep shutdown state. After the pipeline pressure drops to the wake-up threshold, the load will automatically restart and resume stable operation.

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