Direct feed network elevator energy-saving control system

Abstract

An elevator energy-saving control system of a direct feed network relates to the technical field of elevator energy-saving control, and comprises an energy conversion module for converting kinetic energy and gravitational potential energy generated during operation of an elevator car into direct current; the control system module monitors elevator running state data and power grid parameters in real time, judges whether the elevator is in a power generation state or not according to a monitoring result, automatically starts an energy feedback mode and controls starting and stopping of energy feedback and power adjustment; the inversion grid-connected module is used for converting the direct current into alternating current, processing the generated alternating current and feeding back the electric energy in the form of the processed alternating current to a power grid; and the man-machine interaction module is used for receiving data information of the control system in real time and converting the data information into visual display content, so that a worker can master the operation condition of the system in time and deal with abnormal problems. The elevator running energy consumption is remarkably reduced, the running cost is reduced, meanwhile, the service life of equipment is prolonged, the stability of the equipment is improved, and the influence on the environment is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of elevator energy-saving control, and more particularly to a direct-grid-fed elevator energy-saving control system. Background Art

[0002] With the continuous rise in electricity prices in recent years, elevators have become a major concern for many elevator users. In recent years, energy conservation has become a significant consideration when selecting elevators for new buildings, and elevators with energy regeneration devices have gradually become popular among construction companies. A direct-grid-fed elevator energy-saving control system is a highly efficient energy-saving solution that uses technological innovation to recover and reuse elevator energy. Its core approach is to convert the kinetic energy generated during elevator operation into electrical energy and feed it back to the grid, thereby reducing overall energy consumption. When braking or descending, the motor of a traditional elevator generates electricity, and the generated energy is typically dissipated as heat by the braking resistor, resulting in energy waste. A direct-grid-fed system, on the other hand, processes this energy and returns it to the grid for use by other electrical devices, achieving the dual benefits of "energy conservation and grid power supply." Regeneration involves converting excess electricity into AC power with the same phase, frequency, voltage, and phase sequence as the low-voltage grid (local grid) and then feeding it back to the low-voltage grid. This process is very similar to the process of connecting wind and solar power generation to the low-voltage grid.

[0003] Deficiencies in existing technologies:

[0004] In traditional elevator systems, when an elevator is heavily loaded and descending, or when decelerating and braking, the motor switches from "motor mode" to "generator mode," converting the kinetic energy and gravitational potential energy of the elevator car into electrical energy. However, this generated electrical energy is typically dissipated as heat by the braking resistor, resulting in significant energy waste and the need for additional heat dissipation devices, increasing equipment and operating costs while also shortening the lifespan of elevator equipment. Traditional resistor braking generates significant heat, requiring additional heat dissipation devices. Direct grid-fed systems, on the other hand, reduce heat loss, lower machine room temperatures, reduce air conditioning energy consumption, and extend the lifespan of equipment such as motors and cables. While existing energy-saving technologies, such as variable frequency drive (VFD) and permanent magnet synchronous motors (PMSMs), can reduce energy consumption to a certain extent, they cannot effectively address the issue of brake energy waste. Therefore, an energy-saving control system that can recover elevator brake energy and directly feed it back into the grid is urgently needed.

[0005] In view of the above problems, the present invention proposes a solution. Summary of the Invention

[0006] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a direct-grid-fed elevator energy-saving control system, which solves the problems raised in the above-mentioned background technology by efficiently recovering the regenerative electric energy generated during the elevator braking process and directly feeding it back to the power grid.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A direct-grid-fed elevator energy-saving control system includes an energy conversion module, a control system module, an inverter grid-connected module, and a human-computer interaction module. The modules are connected:

[0009] Energy conversion module, used to convert kinetic energy and gravitational potential energy generated during the operation of the car into direct current;

[0010] The control system module monitors the elevator operating status data and grid parameters in real time, and determines whether the elevator is in the power generation state based on the monitoring results. If the power generation conditions are met, the control system automatically starts the energy feedback mode and controls the start and stop of the energy feedback and the power regulation;

[0011] The inverter grid-connected module, when the energy feedback mode is activated, converts the previously generated DC power into AC power, processes the generated AC power, and feeds the processed AC power back to the grid;

[0012] The human-computer interaction module receives data information from the control system in real time, parses and processes the received data information, and converts it into intuitive display content, so that staff can grasp the system operation status in time and deal with abnormal problems.

[0013] In a preferred embodiment, the process of converting the kinetic energy and gravitational potential energy generated by the operation of the elevator car into direct current is as follows:

[0014] When the elevator is running, the car generates kinetic energy during the movement, and at the same time has gravitational potential energy due to the change in height;

[0015] The kinetic energy and gravitational potential energy are transferred to the motor through the elevator's traction system, causing the motor to change from a motoring state to a generating state under heavy-load descending and deceleration braking;

[0016] The generated alternating current is rectified by a rectifier to convert the alternating current into pulsating direct current.

[0017] In a preferred embodiment, the operating status data includes elevator operating speed data, car load weight, and car location information, and the grid parameters include grid current, voltage, frequency, and phase.

[0018] In a preferred embodiment, the process of determining whether the elevator is in a power generation state according to the monitoring results is as follows:

[0019] The control system comprehensively analyzes the elevator operation status data and grid parameters collected.

[0020] When it is detected that the load in the elevator exceeds the preset ratio of the rated load or the speed change rate exceeds the set threshold condition, and the real-time power is greater than the power generation power threshold, it is immediately determined that the elevator is in the power generation state, and the energy feedback mode is automatically started.

[0021] On the contrary, if the power generation conditions are not met, the energy is consumed through traditional means.

[0022] In a preferred embodiment, the start-stop and power regulation of the energy feedback are as follows:

[0023] During the energy feedback process, the control system adjusts the switching frequency and duty cycle of the inverter according to the real-time monitored data through the PID control algorithm, so as to achieve the start-stop control of the energy feedback and the regulation of the power magnitude.

[0024] In a preferred embodiment, the process of converting the previously generated direct current into alternating current by the inverter grid connection device is as follows:

[0025] The direct current output by the energy conversion module enters the inverter, and the inverter inversely converts the direct current into alternating current through the high-frequency switching action of the power switching device.

[0026] In a preferred embodiment, the process of processing the generated alternating current is as follows:

[0027] Adopting the high-performance phase-locked loop technology, the grid voltage signal is collected in real time, the grid frequency is calculated by the digital signal processor, and the frequency of the alternating current output by the inverter is locked within the range where the difference from the grid frequency is ≤0.1Hz. When the grid frequency fluctuates, the response time of the PLL is ≤10ms to ensure real-time frequency tracking.

[0028] Regarding the sine pulse width modulation technology, the modulation ratio M (0<M<1) is dynamically adjusted according to the grid voltage amplitude. The effective value of the grid voltage is monitored in real time through the voltage sensor. The control system adjusts the amplitude Urm of the modulation wave through the PID algorithm according to the error between the target voltage and the actual output voltage, so that the difference between the voltage output by the inverter and the grid voltage is ≤5V to ensure the voltage matching accuracy.

[0029] The phase difference Δφ between the output alternating current and the grid voltage is calculated in real time through the PLL algorithm. When Δφ exceeds 3°, the phase compensation is immediately carried out by adjusting the control signal of the inverter, and Δφ is controlled within ±1° to avoid the reactive power loss caused by the phase deviation.

[0030] In a preferred embodiment, the process of feeding back the processed electrical energy in the form of alternating current to the grid is as follows:

[0031] After the voltage, frequency and phase are adjusted, the AC power is first electrically isolated by an isolation transformer to reduce the impact of grid interference on the module, and then the processed AC power is fed back to the grid through the grid-connected circuit breaker.

[0032] In a preferred embodiment, the process of receiving data information from the control system in real time is as follows:

[0033] Data communication is carried out with the control system through the communication interface, and system operation status data, energy consumption data and fault information sent by the control system are received in real time.

[0034] In a preferred embodiment, the received data information is parsed and processed, and converted into intuitive display content as follows:

[0035] Parse the received raw data information and convert it from binary machine-readable format into parameters and information understandable to staff;

[0036] Convert the parsed and processed data information into a variety of intuitive display contents. For the system operation status, dynamic icons are used to show the elevator's running direction and whether it is in energy feedback mode;

[0037] For energy consumption data, the power generation trend and cumulative power generation in different time periods are displayed in the form of line graphs and bar graphs;

[0038] Fault information is presented in the form of a combination of eye-catching text prompts and fault codes, with a simple description of the cause of the fault.

[0039] The technical effects and advantages of the direct-grid-fed elevator energy-saving control system of the present invention are as follows:

[0040] 1. This invention uses an energy conversion module to precisely capture the kinetic energy and gravitational potential energy generated by an elevator during heavy descent and deceleration. When an elevator carrying a heavy load descends, the gravitational potential energy is continuously released as the elevator car descends. During deceleration and braking, the kinetic energy of the elevator car is also rapidly converted into usable energy. This energy is converted into direct current (DC) through the electromagnetic induction of the motor, which is then rectified and filtered before entering the inverter-grid-connected module. The inverter-grid-connected module, leveraging advanced power electronics technology, converts the DC power into AC power with the same frequency and phase as the power grid. Sinusoidal pulse-width modulation (PWM) technology precisely controls relevant parameters to ensure output voltage stability, while phase-locked loop (PLL) technology tracks the power grid phase in real time, minimizing phase deviations and significantly reducing energy losses caused by phase mismatch. Data shows that this system achieves energy recovery efficiencies of 30 to 70 percent. In high-rise buildings with frequent elevator use, a single high-power elevator can save tens of thousands of yuan in electricity bills annually, a significant improvement compared to traditional variable-frequency speed regulation (VVVV) and permanent magnet synchronous motor (PMSM) technologies. More importantly, this energy saving is not simply a single optimization step; it encompasses a systemic improvement throughout the entire elevator operation cycle. During each stage of elevator startup, operation, and braking, the control system dynamically adjusts the energy recovery strategy by monitoring parameters such as speed and load in real time, ensuring efficient energy conversion under different operating conditions. For example, during the morning rush hour, when elevators frequently start and stop, the system can quickly respond to each braking process, effectively recovering brief energy pulses, and accumulating them into significant energy savings.

[0041] 2. The present invention improves the operating environment of the equipment from the source by reducing heat emission.

[0042] By eliminating the need for resistors to dissipate energy, the machine room temperature can be reduced by five to ten degrees Celsius. This not only reduces the load on the air conditioning system but also keeps the motor's operating temperature within a more reasonable range. The insulation properties of the motor windings are better maintained at suitable temperatures, preventing insulation aging and short-circuit failures caused by high temperatures. Furthermore, the system's safety protection module features multiple protections, including overvoltage, overcurrent, short-circuit, and leakage protection. When it detects that the current exceeds a set threshold, it immediately disconnects the circuit, preventing high current from impacting the motor and other electrical components. Furthermore, the control system's intelligent regulation function plays a crucial role in protecting the equipment. Using relevant control algorithms, the system precisely controls the power and rhythm of energy feedback, preventing energy backflow from damaging the power grid and the elevator's internal circuitry. During elevator startup and shutdown, smooth power regulation reduces shock to the mechanical transmission system, minimizing wear on components like the gearbox and traction sheave, significantly extending the equipment's maintenance cycle and service life. According to actual case studies, elevators using this system can extend the replacement cycle of core components by two to three years, significantly reducing equipment operation and maintenance costs. With the rapid development of the energy internet, elevators, as key electrical equipment in buildings, are increasingly valued for their compatibility with the power grid. Direct-grid-fed elevator energy-saving control systems utilize a series of advanced technologies to ensure that energy feedback does not interfere with the grid, but rather supports its stable operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a structural diagram of an elevator energy-saving control system with direct grid feeding according to the present invention.

[0044] Figure 2 This is a working principle diagram of the elevator power feedback unit of the present invention. DETAILED DESCRIPTION

[0045] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0046] In traditional elevator operation, the energy generated during braking is often directly dissipated as heat through the braking resistor. This not only results in significant energy waste, but also increases the temperature in the machine room and the energy consumption of auxiliary equipment such as air conditioners. The direct-grid-fed elevator energy-saving control system fundamentally changes this situation. By integrating the energy conversion module with the inverter grid-connected module, it establishes a complete energy recovery closed loop.

[0047] Traditional elevators often experience high machine room temperatures due to the constant heating of their braking resistors. This accelerates the aging of core components like motors, cables, and control systems. Data shows that for every ten-degree Celsius increase in ambient temperature, the lifespan of electronic components is reduced by approximately half. Direct-grid-fed elevator energy-saving control systems, however, improve the equipment's operating environment by reducing heat emissions.

[0048] Example 1, Figure 1 The present invention provides an elevator energy-saving control system with direct network feeding.

[0049] When we lift a heavy object from a low place to a high place, we expend energy. When we lower the object back down, this energy is released. This is the principle of "conservation of energy." The same principle applies to elevators: when we lift an elevator, we use electrical energy, and when we lower it, we release energy. To ensure even load distribution, the load pulled by the elevator's traction motor consists of a passenger car and a counterweight. The two are balanced only when the car's load plus 50% of the car's rated load are equal. This change changes the peak energy consumption point, but it does not change the average energy consumption. In actual use, it is rare for the weight of the car plus the weight of the passengers to exactly equal the weight of the counterweight. Therefore, elevators essentially operate in an unbalanced state.

[0050] Energy conversion module, used to convert kinetic energy and gravitational potential energy generated during the operation of the car into direct current;

[0051] When the elevator is running, the car generates kinetic energy during the movement, and at the same time has gravitational potential energy due to the change in height;

[0052] These mechanical energies are transmitted to the motor through the elevator's traction system, so that the motor changes from the electric state to the power generation state under specific working conditions (such as heavy load descent, deceleration braking);

[0053] When the motor is generating electricity, the internal rotor rotates in the stator magnetic field. According to the law of electromagnetic induction, part of the conductor of the closed circuit cuts the magnetic flux lines in the magnetic field, thereby generating an induced electromotive force, forming the prototype of direct current.

[0054] The generated alternating current is rectified by a rectifier (such as a bridge rectifier circuit) to convert the alternating current into pulsating direct current; the pulsating direct current is then filtered by a capacitor filter circuit to smooth the voltage waveform and obtain a relatively stable direct current output.

[0055] This process is a physical phenomenon triggered by mechanical movement. It objectively occurs before the control system makes a judgment and is the basis of energy recovery.

[0056] The control system module monitors the elevator operating status data and grid parameters in real time, and determines whether the elevator is in the power generation state based on the monitoring results. If the power generation conditions are met, the control system automatically starts the energy feedback mode and controls the start and stop of the energy feedback and the power regulation;

[0057] The operating status data includes elevator operating speed data, car load weight, and car location information; the grid parameters include grid current, voltage, frequency, and phase;

[0058] Various sensors installed on the elevator, such as speed sensors (such as encoders) collect elevator speed data; weighing sensors collect car weight; position sensors (such as magnetic switches, absolute encoders) obtain car location information;

[0059] At the same time, the voltage and current data of the power grid are collected through voltage sensors and current sensors, and the frequency and phase parameters of the power grid are then calculated.

[0060] The control system conducts a comprehensive analysis of the collected elevator operating status data and grid parameters. When it detects that the elevator is in a heavily loaded downward state (the load exceeds a preset percentage of the rated load) or decelerating braking (the speed change rate exceeds a set threshold), and the real-time power is greater than the power generation power threshold, it immediately determines that the elevator is in a power generation state and then starts the energy feedback mode.

[0061] On the contrary, if the power generation conditions are not met, the energy will be consumed through traditional means.

[0062] At this point, the energy conversion is already in the initial stage (generating direct current), and the judgment process is carried out in parallel with the initial stage of energy conversion, rather than waiting for the energy conversion to be completed before making a judgment.

[0063] The physical process of energy conversion starts before the judgment logic, but the judgment process is carried out simultaneously at the initial stage of energy conversion and determines whether the energy enters the subsequent grid-connected utilization stage. The two form a closed-loop linkage through real-time monitoring to ensure the efficiency and accuracy of energy recovery.

[0064] During the energy feedback process, the control system adjusts the switching frequency and duty cycle of the inverter through the PID control algorithm based on real-time monitoring data, thereby achieving start and stop control of energy feedback and precise adjustment of power size, ensuring stable and efficient energy feedback.

[0065] Energy is no longer dissipated through resistors, reducing the room temperature by five to ten degrees Celsius. This not only reduces the operating load on the air conditioning system but also keeps the motor's operating temperature within a more reasonable range. The insulation performance of the motor windings is better maintained at the appropriate temperature, preventing insulation aging and short-circuit failures caused by high temperatures. Furthermore, the system's safety protection module features multiple protections for overvoltage, overcurrent, short circuit, and leakage. When it detects that the current exceeds a set threshold, it immediately shuts off the circuit to prevent high current from impacting the motor and other electrical components.

[0066] Furthermore, the control system's intelligent regulation function also plays a crucial role in protecting the equipment. Using relevant control algorithms, the system precisely controls the power and rhythm of energy feedback, preventing damage to the power grid and the elevator's internal circuitry from energy backflow. During elevator startup and shutdown, smooth power regulation reduces shock to the mechanical transmission system and reduces wear on components like the gearbox and traction sheave, significantly extending the equipment's maintenance cycle and service life. According to actual case studies, elevators using this system can extend the replacement cycle of core components by two to three years, significantly reducing equipment operation and maintenance costs.

[0067] The inverter grid-connected module, when the energy feedback mode is activated, converts the previously generated DC power into AC power, processes the generated AC power, and feeds the processed AC power back to the grid;

[0068] The DC power output by the energy conversion module enters the inverter, which converts the DC power into AC power through the high-frequency switching action of power switching devices (such as IGBTs).

[0069] To reduce energy loss during the conversion process, low on-resistance power devices are used, and switching losses are reduced by optimizing the switching frequency (for example, dynamically adjusting it within the 5kHz-20kHz range based on real-time power consumption). At the same time, through precise drive circuit design, the turn-on and turn-off time errors of the switching devices are controlled within microseconds, reducing energy waste during the transition process.

[0070] By precisely controlling the matching degree between the inverter output and the grid, the energy feedback efficiency is greatly improved. The generated AC power is processed as follows:

[0071] High-performance phase-locked loop (PLL) technology is used to collect grid voltage signals in real time. The grid frequency (e.g., 50Hz±0.5Hz) is calculated using a digital signal processor (DSP). The inverter output AC power frequency is locked within a range of ≤0.1Hz from the grid frequency. When the grid frequency fluctuates, the PLL response time is ≤10ms, ensuring real-time frequency tracking.

[0072] Regarding the sine pulse width modulation (SPWM) technology, the modulation ratio M (0 < M < 1) is dynamically adjusted according to the amplitude of the grid voltage. The effective value of the grid voltage (such as 220V ± 10%) is monitored in real time through a voltage sensor. The control system adjusts the amplitude Urm of the modulation wave through the PID algorithm according to the error between the target voltage and the actual output voltage, so that the difference between the output voltage of the inverter and the grid voltage is ≤ 5V, ensuring the voltage matching accuracy;

[0073] The phase difference Δφ between the output alternating current and the grid voltage is calculated in real time through the PLL algorithm. When Δφ exceeds 3°, phase compensation is immediately carried out by adjusting the control signal of the inverter (such as delaying or advancing the trigger pulse), and finally Δφ is controlled within ±1°, avoiding reactive power loss caused by phase deviation.

[0074] The alternating current after voltage, frequency, and phase adjustment is first electrically isolated through an isolation transformer (reducing the impact of grid interference on the module), and then the processed electrical energy in the form of alternating current is fed back to the grid through a grid connection circuit breaker.

[0075] To reduce the grid connection line loss, low-impedance cables are selected, and high-permeability iron core materials are used in the transformer design to control the transformer loss within 2%. At the same time, a harmonic filter (such as an LC filter) is set at the grid connection interface to suppress high-frequency harmonics (the total content of the 3rd, 5th, and 7th harmonics ≤ 3%), avoiding additional losses generated by harmonic currents on the grid impedance and further improving the effective utilization rate of energy feedback.

[0076] In the context of the rapid development of the energy Internet, elevators, as important power-consuming equipment in buildings, their compatibility with the grid has received increasing attention. The elevator energy-saving control system with direct grid connection adopts a series of advanced technologies to ensure that it does not interfere with the grid during the energy feedback process, but can provide support for the stable operation of the grid.

[0077] The inverter grid connection module of the system controls the harmonic content of the output electrical energy within 5% through harmonic suppression technology, which means that the electrical energy fed back to the grid will not cause harmonic interference to other electrical equipment, avoiding problems such as light flickering and measurement errors of precision instruments. At the same time, through power factor correction technology, the power factor of the system is maintained above 0.95, reducing the transmission of reactive power and improving the transmission efficiency of the grid.

[0078] The system is capable of rapid response to grid voltage fluctuations. With a phase-locked loop (PLL) response time of less than ten milliseconds, it can quickly adjust the output voltage and frequency to maintain synchronization with the grid. In the event of a grid fault or voltage drop, the grid-connected circuit breaker quickly trips, preventing the elevator system from backfeeding power to the grid and ensuring the safety of grid maintenance personnel. This two-way protection mechanism enables elevators to not only be power consumers but also, in certain circumstances, become "friendly partners" of the grid, potentially supporting the peak-load shifting and valley-shaving capabilities of smart grids.

[0079] The human-computer interaction module receives data information from the control system in real time, parses and processes the received data information, and converts it into intuitive display content, so that staff can grasp the system operation status in time and deal with abnormal problems.

[0080] The human-computer interaction module communicates data with the control system through a communication interface (such as RS485, Ethernet interface), and receives in real time system operation status data (such as elevator speed, position, energy feedback status), energy consumption data (such as generated power, feedback power) and fault information (such as overvoltage, overcurrent, short circuit and other fault codes) sent by the control system.

[0081] The system parses the received raw data, converting it from machine-readable formats like binary into parameters and information understandable to staff. For example, the system converts the received pulse signal representing elevator speed into a specific speed value (m / s) based on speed calculation rules. Energy consumption data is integrated and processed according to the logic for cumulative power generation to obtain cumulative power generation for different time periods (e.g., hourly, daily, and monthly). The system also verifies the data to ensure its accuracy and completeness, eliminating invalid or erroneous data.

[0082] The parsed and processed data is converted into a variety of intuitive displays. Dynamic icons display the system's operating status, such as the elevator's direction of travel (up, down), whether it's in energy regeneration mode, and other indicators. Energy consumption data is displayed using line charts and bar graphs, showing power generation trends and cumulative power generation over different time periods. Fault information is presented using a combination of prominent text (e.g., red font) and fault codes, along with a brief explanation of the cause of the fault. These displays are displayed on a liquid crystal display (LCD) or touchscreen, allowing staff to quickly access the required information by switching between different display pages through touch.

[0083] When a system failure occurs, the human-computer interaction module not only displays the fault information but also issues audible and visual alarm signals (such as a beeping buzzer and flashing warning lights) to promptly alert personnel. The display also provides troubleshooting guidance. For example, in the case of an overvoltage fault, it prompts personnel to check whether the grid voltage is normal and whether the inverter voltage regulation module is functioning properly. Based on this information, personnel can quickly locate the fault point and take appropriate action, shortening troubleshooting time and ensuring the system resumes normal operation as soon as possible.

[0084] The human-computer interaction module acts as a bridge between the system and personnel, greatly improving the management efficiency of the elevator energy-saving control system. The module communicates with the control system in real time through relevant interfaces, displaying system operating status, energy consumption data, fault information, etc. in real time on the LCD screen or touch screen.

[0085] In terms of energy consumption management, the module automatically calculates power generation over different time periods (hourly, daily, and monthly) and presents this information intuitively in line and bar charts. This data allows staff to clearly understand the energy-saving effects of elevators and develop more appropriate operation plans. For example, during peak elevator usage periods in office buildings, energy consumption data analysis can be used to adjust elevator operation strategies and further improve energy recovery efficiency.

[0086] The system's performance is even more outstanding in fault handling. When an equipment anomaly occurs, the human-machine interaction module immediately issues an audible and visual alarm signal and displays the fault code, fault time, and possible cause. Furthermore, by calculating the interval between faults, it helps personnel analyze fault patterns. For example, if a fault recurs frequently within a short period of time, the system will indicate that the relevant component may be aging and requires prompt replacement to prevent further losses due to escalating faults. This early warning and precise location capability reduces fault handling time by over 50%, significantly reducing the impact of elevator outages.

[0087] Elevator energy regeneration technology is a mature and highly scalable energy-saving technology, recognized by national elevator quality management authorities. We consider installing energy regeneration devices in office buildings, commercial buildings, and other structures we manage. This not only saves electricity but also improves the elevator's operating environment and prolongs its lifespan.

[0088] Example 2 provides a working principle diagram of the elevator power feedback unit of the present invention.

[0089] The elevator power feedback device automatically detects the DC bus voltage of the inverter, inverts the DC power of the inverter's DC link into AC power with the same frequency and phase as the grid voltage, and connects it to the AC grid after passing through multiple noise filtering links, thereby achieving the purpose of energy feedback to the grid. The energy conversion rate reaches more than 97%, effectively saving electricity.

[0090] The above formulas are all dimensionless and numerical calculations. The formulas are obtained by collecting a large amount of data and performing software simulation to obtain the most recent real situation. The preset parameters in the formulas are set by technicians in this field according to actual conditions.

[0091] The above embodiments may be implemented in whole or in part through software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments may be implemented in whole or in part in the form of a computer program product.

[0092] Those skilled in the art will appreciate that the modules and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0093] In addition, each functional module in each embodiment of the present application may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module.

[0094] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

[0095] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A direct-grid-fed elevator energy-saving control system, characterized in that: It includes energy conversion module, control system module, inverter grid-connected module, and human-computer interaction module. There are connections between the modules: Energy conversion module, used to convert kinetic energy and gravitational potential energy generated during the operation of the car into direct current; The control system module monitors the elevator operating status data and grid parameters in real time, and determines whether the elevator is in the power generation state based on the monitoring results. If the power generation conditions are met, the control system automatically starts the energy feedback mode and controls the start and stop of the energy feedback and the power regulation; The inverter grid-connected module, when the energy feedback mode is activated, converts the previously generated DC power into AC power, processes the generated AC power, and feeds the processed AC power back to the grid; The human-computer interaction module receives data information from the control system in real time, parses and processes the received data information, and converts it into intuitive display content, so that staff can grasp the system operation status in time and deal with abnormal problems.

2. The direct-grid-fed elevator energy-saving control system according to claim 1, characterized in that: The process of converting the kinetic energy and gravitational potential energy generated by the operation of the car into direct current is as follows: When the elevator is running, the car generates kinetic energy during the movement, and at the same time has gravitational potential energy due to the change in height; The kinetic energy and gravitational potential energy are transferred to the motor through the elevator's traction system, causing the motor to change from a motoring state to a generating state under heavy-load descending and deceleration braking; The generated alternating current is rectified by a rectifier to convert the alternating current into pulsating direct current.

3. The direct-grid-fed elevator energy-saving control system according to claim 2, characterized in that: The operating status data includes elevator operating speed data, car load weight, and car location information, and the grid parameters include grid current, voltage, frequency, and phase.

4. The direct-grid-fed elevator energy-saving control system according to claim 3, characterized in that: The process of judging whether the elevator is in power generation state based on the monitoring results is as follows: The control system conducts a comprehensive analysis of the collected elevator operation status data and power grid parameters; When it is detected that the load at the elevator exceeds the preset ratio of the rated load or the speed change rate exceeds the set threshold, and the real-time power is greater than the power generation power threshold, the elevator is immediately determined to be in the power generation state and the energy feedback mode is automatically started; On the contrary, if the power generation conditions are not met, the energy will be consumed through traditional means.

5. The direct-grid-fed elevator energy-saving control system according to claim 4, characterized in that: The start and stop and power regulation process of controlling energy feedback is as follows: During the energy feedback process, the control system adjusts the switching frequency and duty cycle of the inverter through the PID control algorithm based on real-time monitoring data, thereby realizing the start and stop control of energy feedback and power regulation.

6. The direct-grid-fed elevator energy-saving control system according to claim 5, characterized in that: The process of the inverter grid-connected device converting the previously generated DC power into AC power is as follows: The DC power output by the energy conversion module enters the inverter, which converts the DC power into AC power through the high-frequency switching action of the power switching device.

7. The direct-grid-fed elevator energy-saving control system according to claim 6, characterized in that: The process of processing the generated alternating current is as follows: High-performance phase-locked loop technology is used to collect grid voltage signals in real time, calculate the grid frequency through a digital signal processor, and lock the frequency of the inverter's AC output to a range of ≤0.1Hz from the grid frequency. When the grid frequency fluctuates, the PLL response time is ≤10ms, ensuring real-time frequency tracking. Regarding the sine pulse width modulation technology, the modulation ratio M (0 < M < 1) is dynamically adjusted according to the amplitude of the grid voltage. The effective value of the grid voltage is monitored in real time through a voltage sensor. The control system adjusts the amplitude Urm of the modulation wave through the PID algorithm according to the error between the target voltage and the actual output voltage, so that the difference between the inverter output voltage and the grid voltage is ≤ 5V, ensuring the voltage matching accuracy; The phase difference Δφ between the output alternating current and the grid voltage is calculated in real time through the PLL algorithm. When Δφ exceeds 3°, the phase compensation is immediately carried out by adjusting the control signal of the inverter, and Δφ is controlled within ±1°, avoiding the reactive power loss caused by the phase deviation.

8. The direct-grid-fed elevator energy-saving control system according to claim 7, characterized in that: The process of feeding back the processed electrical energy in the form of alternating current to the grid is as follows: The alternating current after voltage, frequency, and phase adjustment is first electrically isolated through an isolation transformer to reduce the influence of grid interference on the module, and then the processed electrical energy in the form of alternating current is fed back to the grid through a grid connection circuit breaker.

9. The direct-grid-fed elevator energy-saving control system according to claim 8, characterized in that: The process of receiving the data information of the control system in real time is as follows: Data communication is carried out with the control system through the communication interface, and the system operation status data, energy consumption data, and fault information sent by the control system are received in real time.

10. The direct-grid-fed elevator energy-saving control system according to claim 9, characterized in that: The process of parsing and processing the received data information and converting it into intuitive display content is as follows: Parse the received original data information and convert it from a binary machine-readable format into parameters and information understandable by the staff; Convert the parsed and processed data information into various intuitive display contents. For the system operation status, the running direction of the elevator and whether it is in the energy feedback mode are shown through dynamic icons; For the energy consumption data, the change trend of the power generation power and the cumulative power generation amount in different time periods are shown in the form of line charts and bar charts; For the fault information, it is presented in a combination of text prompts and fault codes, and the cause of the fault is explained.

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