Variable-frequency energy-saving energy feedback device of elevator equipment

Abstract

The invention relates to a frequency-conversion energy-saving energy feedback device of elevator equipment, which belongs to the field of elevator equipment, and comprises a higher harmonic filtering module for filtering higher harmonics in accessed direct current so as to smooth direct current voltage; the higher harmonic filter reactor absorbs and filters higher harmonic current in a power grid; the PWM frequency converter controls the voltage and the frequency of the alternating-current electric energy output by the energy feedback converter by adjusting a PWM signal; the energy feedback converter converts direct-current electric energy into alternating-current electric energy with the same frequency and phase as the voltage of the power grid for feedback, the rectifier rectifies the generated direct-current electric energy and stores the direct-current electric energy in the capacitor, then the energy feedback converter converts the direct-current electric energy into alternating-current electric energy, and the converted alternating-current electric energy is fed back to the power grid. The device is used by other equipment; and the MEMOBUS communication module realizes conversion, output and input of a protocol. According to the device, the level noise generated when the motor works is effectively reduced, and the stability and the reliability of system operation are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of elevator equipment, and particularly relates to a variable-frequency energy-saving energy feedback device for elevator equipment. Background Art

[0002] With the increasing prominence of energy problems and the popularization and strengthening of environmental protection awareness, at present, elevator energy feedback systems are beginning to be adopted in buildings to achieve energy conservation and emission reduction and energy consumption reduction. However, in the actual application process, the defects of this system have gradually emerged.

[0003] The main disadvantages of the existing elevator energy feedback systems are as follows:

[0004] (1) Efficiency problem: Although the original design intention is to improve energy efficiency, recover electric energy and reduce energy consumption, the actual effect is often not satisfactory. In some cases, the actual working efficiency is not high, and may even be lower than the expected value, unable to achieve the expected economic and environmental benefits.

[0005] (2) High cost: Compared with the consumption of traditional electricity, introducing a new elevator energy feedback device will significantly increase the installation and maintenance costs, which will bring certain economic pressure to enterprises in the short term. Even in the long run, a large amount of funds need to be invested in maintenance and management to ensure its normal operation, and the service life is still uncertain, making the return on investment difficult to predict.

[0006] (3) Insufficient stability and reliability: Due to the complexity of technology and application environment, failures or instabilities may occur under extreme conditions, resulting in a certain impact on elevator operation and even safety problems, which also limits its promotion and application in a wider range of fields.

[0007] (4) Great limitations in application scenarios: At present, most energy feedback systems are more applied in high-rise buildings, and are less suitable for low-rise buildings or old buildings, because there may be compatibility problems between the traditional electrical systems and modern intelligent control systems in such buildings, which requires additional transformation and adjustment, increasing the implementation difficulty and economic burden.

[0008] In summary of the above problems, although the elevator energy feedback technology has significant energy-saving and environmental protection advantages in theory, it still faces various challenges and deficiencies in the actual operation process. Summary of the Invention

[0009] The purpose of the present invention is to solve at least one of the above technical defects.

[0010] For this reason, the purpose of the present invention is to provide a variable-frequency energy-saving energy feedback device for elevator equipment, which can effectively reduce the level noise generated by the motor during operation and improve the stability and reliability of system operation.

[0011] To achieve the above object, an embodiment of the present invention provides a variable-frequency energy-saving energy feedback device for an elevator device, including: a high-order harmonic filtering module, a high-order harmonic filtering reactor, an energy feedback converter, a PWM frequency converter, and a MEMOBUS communication module, where,

[0012] The high-order harmonic filtering module is used to filter out high-order harmonics in the accessed direct current to smooth the DC voltage;

[0013] One end of the high-order harmonic filtering reactor is connected to the high-order harmonic filtering module, and the other end is connected to the energy feedback converter. The high-order harmonic filtering reactor is used to absorb and filter out high-order harmonic currents in the power grid to avoid resonance;

[0014] The PWM frequency converter is connected to the energy feedback converter and the traction machine, and is used to generate the switching signals required by the energy feedback converter. By adjusting the duty cycle and frequency of the PWM signal, it controls the voltage and frequency of the alternating current energy output by the energy feedback converter;

[0015] The energy feedback converter is used to convert DC electrical energy into AC electrical energy with the same frequency and phase as the grid voltage for feedback. Among them, during the elevator energy feedback process, when the traction machine is in the power generation state, the rectifier rectifies the generated direct current and stores it in the capacitor. Then, the energy feedback converter converts the above DC electrical energy into AC electrical energy, and under the control of the PWM signal, adjusts the phase of the output current of the internal switching device to make the difference between its phase and the phase of the grid voltage tend to become smaller; the converted AC electrical energy is fed back to the power grid for other devices to use;

[0016] The MEMOBUS communication module is connected to the energy feedback converter and is used to implement protocol conversion, output, and input.

[0017] Further, the high-order harmonic filtering module includes a filtering capacitor, and the filtering capacitor is connected to the high-order harmonic filtering reactor for reactive power compensation and filtering out high-order harmonics.

[0018] Further, the PWM frequency converter adopts sinusoidal pulse width modulation SPWM technology to generate corresponding PWM signals according to the instantaneous value of the sine wave.

[0019] Further, the PWM signal output by the PWM frequency converter controls the switching devices in the energy feedback converter, and adjusts the on and off times of the switching devices to control the shape and phase of the output current.

[0020] Further, the energy feedback converter further includes: a controller, which monitors the grid voltage and current in real time, calculates the phase difference based on the monitored voltage and current signals, and adjusts the switching states of the switching devices according to the phase difference to gradually reduce the phase difference.

[0021] Further, the controller is also used to monitor the operating state of the elevator and the power generation situation of the traction machine, and adjust the output power and recovery power of the converter according to the actual situation to ensure that the traction machine operates in an optimal state.

[0022] Further, the switching devices are composed of multiple groups of IGBT units to form a control loop.

[0023] Further, the energy feedback converter further includes: a multi-functional analog input terminal, a multi-functional opto-coupler output terminal, a multi-functional analog monitoring output terminal, a multi-functional contact output terminal, a fault contact output terminal, a shielding layer connection terminal, and a toggle switch.

[0024] Further, the MEMOBUS communication module uses RS485 and RS422 interfaces and is connected to the toggle switch.

[0025] Further, the frequency conversion energy-saving energy feedback device of the elevator equipment is connected to multiple elevators to transfer electric energy between multiple elevators.

[0026] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0027] (1) The present invention converts the heat generated during the operation of the elevator into energy for recycling, improves the elevator life, and can generate economic benefits. The dissipated renewable energy is no longer discarded.

[0028] (2) Through the power regeneration technology, the present invention can recover and reuse the energy generated by the motor (i.e., the traction machine) during the braking process, thereby reducing the energy dissipated in the form of heat and further achieving the energy-saving effect.

[0029] (3) Through the power factor control of the power supply and the sine wave PWM control, the present invention can make the phase difference between the current and the voltage smaller, thereby improving the power factor and making the utilization of electric energy more efficient. In the optimal state, the power factor should be as close as possible. Through this design, the utilization of electric energy is made more efficient.

[0030] (4) Since high-order harmonics can cause energy waste and equipment heating, and even affect the stable operation of the power grid, the present invention reduces the heating loss by suppressing high-order harmonics, meets international standards, and does not require additional harmonic suppression equipment, thereby saving equipment costs and reducing electricity bills.

[0031] (5) The intelligent control algorithm built into the present invention can monitor the load change in real time and automatically adjust the output frequency and voltage, ensuring that the motor (i.e., the traction machine) always operates in the optimal state and reducing unnecessary power consumption.

[0032] (6) Through the analog output and communication network of the present invention, users can conveniently monitor key indicators such as power consumption, power savings, electricity bills, and power factors, helping users better understand the operating status of the equipment and optimize operations.

[0033] (7) Compared with traditional energy feedback, the present invention adopts a multi - elevator system. First, it coordinates power generation and consumption among multiple elevators, and second, it feeds back power to the power grid through an energy feedback device. This can greatly reduce the power of the feedback device (more optimal in terms of cost, volume, failure rate, etc.). At the same time, due to the direct power consumption relationship, the harmonic frequency of the power fed back to the power grid is reduced.

[0034] (8) The energy feedback technology of the present invention can effectively reduce the level noise generated by the motor (i.e., the traction machine) during operation, improving the stability and reliability of the system operation.

[0035] (9) Compared with traditional drive methods, the energy feedback technology of the present invention can use components with smaller volumes, thus optimizing the equipment volume.

[0036] (10) Since there is no resistive heating element, the temperature of the machine room drops, which can save the power consumption of the machine room air conditioner.

[0037] (11) By feeding back the regenerative electric energy of the elevator to the elevator and for use by other surrounding devices, the power saving rate can reach 30% - 45%.

[0038] (12) Reduce the influence of circulating current on other devices and circuits, increase the service life of the equipment, and ensure the safe operation of the equipment.

[0039] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The above - mentioned and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0041] Figure 1 is a structural diagram of a variable - frequency energy - saving energy feedback device for an elevator equipment according to an embodiment of the present invention;

[0042] Figure 2 is a schematic diagram of a variable - frequency energy - saving energy feedback device for an elevator equipment according to an embodiment of the present invention;

[0043] Figure 3System connection diagram of the variable-frequency energy-saving energy feedback device for an elevator device according to an embodiment of the present invention. Detailed implementation manners

[0044] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0045] As Figure 1 and Figure 2 shown, the variable-frequency energy-saving energy feedback device for an elevator device according to an embodiment of the present invention includes: a high-order harmonic filtering module 1, a high-order harmonic filtering reactor 2, an energy feedback converter 3, a PWM frequency converter 4, and a MEMOBUS communication module 5.

[0046] A three-phase AC power supply outputs alternating current to a rectification module. After the rectification module converts the alternating current into direct current, it is transmitted to the high-order harmonic filtering module 1. The high-order harmonic filtering module 1 filters out high-order harmonics in the input direct current to smooth the DC voltage.

[0047] The high-order harmonic filtering module 1 filters out high-order harmonics through a filtering circuit, reducing the interference of high-order harmonics on power equipment and ensuring the normal operation of power equipment and the power grid. High-order harmonics generally refer to harmonics with frequencies higher than the fundamental frequency, such as harmonics above the 6th order. These harmonics can cause problems such as overheating, noise, and vibration of equipment such as motors, transformers, and capacitors, and even cause equipment failures. The high-order harmonic filtering module 1 can effectively filter out these high-order harmonics, thereby reducing their interference and influence on the circuit and system.

[0048] In addition, the high-order harmonic filtering module 1 also has the function of suppressing high-frequency harmonics, such as harmonics in the range of 10 KHz to 30 MHz. High-frequency harmonics will have an adverse impact on the stability of the power system and the service life of equipment.

[0049] The high-order harmonic filtering module 1 can effectively protect power equipment and extend its service life. For example, it reduces overheating and failure rates of equipment such as motors and transformers, and improves the service life of the equipment. The high-order harmonic filtering module 1 improves the power factor of the system by reducing harmonic components, thereby reducing power losses and improving the efficiency and reliability of the power system.

[0050] Specifically, the high-order harmonic filtering module 1 includes filtering capacitors. The filtering capacitors are connected to the high-order harmonic filtering reactor 2 for reactive power compensation and filtering out high-order harmonics. One end of the high-order harmonic filtering reactor 2 is connected to the high-order harmonic filtering module 1, and the other end is connected to the energy feedback converter 3. The high-order harmonic filtering reactor 2 (i.e. Figure 2The input AC reactor is used to absorb and filter out high-order harmonic currents in the power grid to avoid resonance and prevent the harm of harmonics to the power grid and equipment.

[0051] The filtering capacitor is used to smooth the DC voltage after rectification. The selection of the capacitance value of the filtering capacitor will affect the ripple size of the DC voltage and the dynamic response of the system. A larger capacitance value can reduce the ripple, but it will also increase the volume and cost of the system. Therefore, a trade-off needs to be made between ripple suppression and system volume.

[0052] In a high-order harmonic environment, the filtering capacitor can perform reactive power compensation by cooperating with the reactor, effectively filtering out high-order harmonics in the system, avoiding resonance, and reducing the harm of harmonics to power equipment. This combination can not only effectively filter out system harmonics, avoid resonance, but also reduce the large inflow of harmonics and protect the normal operation of power capacitors. In addition, the filtering capacitor can improve the stability and reliability of the circuit.

[0053] In addition, the high-order harmonic filtering reactor 2 has the following functions:

[0054] 1) Limiting short-circuit current: In the power system, the reactor can effectively limit the short-circuit current and protect electrical equipment from excessive current shocks. For example, installing a reactor at the outlet of a transformer and a generator can reduce the current peak during a short-circuit fault and reduce the damage to the equipment.

[0055] 2) Improving power factor: The reactor can be used to compensate for reactive power, improve the power factor of the system, and thus improve the efficiency of the power system. By reasonably configuring the reactor, the line loss can be reduced and the power supply quality can be improved.

[0056] 3) Reactive power compensation: The reactor can be used in combination with other reactive power compensation devices (such as capacitors) to achieve reactive power balance in the system and optimize the operation of the power system.

[0057] 4) Limiting inrush current: When starting a high-power motor, the reactor can limit the starting current and reduce the impact on the power grid.

[0058] 5) Voltage regulation: The reactor can be used to regulate the voltage and maintain voltage stability.

[0059] 6) Isolation and protection: The reactor can act as an isolation component to protect the circuit from external interference.

[0060] 7) Reducing electromagnetic interference: The reactor can be used to reduce electromagnetic interference and improve the stability of the equipment.

[0061] 8) Controlling current: The reactor can be used to control the magnitude of the current to adapt to different working conditions.

[0062] 9) Filtering and Voltage Regulation: In power electronic devices, reactors are commonly used in filter circuits to smooth the output voltage and current and reduce ripples. In addition, reactors can also be used in voltage regulation circuits to stabilize the output voltage and prevent the impact of voltage fluctuations on the load.

[0063] The PWM frequency converter 4 is connected to the energy feedback converter 3 and the traction machine, and is used to generate the switching signals required by the energy feedback converter 3 (with an inverter built-in). By adjusting the duty cycle and frequency of the PWM signal, it controls the voltage and frequency of the AC electrical energy output by the energy feedback converter 3. Among them, the duty cycle and frequency of the PWM signal need to be adjusted according to specific factors such as the elevator load and grid conditions.

[0064] The following separately explains the duty cycle and frequency of the PWM signal:

[0065] Duty Cycle of the PWM Signal: The duty cycle refers to the proportion of the high level in the PWM signal. In sinusoidal PWM (SPWM) control, the duty cycle is dynamically adjusted according to the instantaneous value of the sinusoidal wave to simulate the waveform of the sinusoidal wave. For example, near the peak of the sinusoidal wave, the duty cycle may be close to 100% or 0%, and near the midpoint of the sinusoidal wave, the duty cycle may be close to 50%.

[0066] Frequency of the PWM Signal: The frequency of the PWM signal determines the switching speed of the inverter switching devices. A higher frequency can reduce the harmonic components of the output current and improve the power quality, but it will also increase the switching losses. Therefore, a trade-off needs to be made between harmonic suppression and switching losses. For example, in some elevator energy feedback systems, the frequency of the PWM signal may be set between several kilohertz and dozens of kilohertz.

[0067] To achieve a sinusoidal output, the shape of the PWM signal needs to be precisely controlled to simulate the waveform of the sinusoidal wave. In the embodiments of the present invention, the PWM frequency converter 4 adopts the sinusoidal pulse width modulation SPWM technology to generate corresponding PWM signals according to the instantaneous values of the sinusoidal wave.

[0068] The PWM signal output by the PWM frequency converter 4 controls the switching devices in the energy feedback converter 3, and adjusts the on and off times of the switching devices to control the shape and phase of the output current.

[0069] In the present invention, a power factor control method of the power supply is adopted, that is, by controlling the switching devices (such as IGBTs) of the inverter and adjusting their on and off times, thereby controlling the shape and phase of the output current, so that the phase difference between the output current and the grid voltage is as small as possible, that is, improving the power factor. This involves a power factor correction (PFC) algorithm, which dynamically adjusts the switching state of the inverter according to the real-time detection values of the grid voltage and current.

[0070] The duty cycle and frequency of the PWM signal are adjusted according to specific factors such as the elevator load and grid conditions.

[0071] The reduction of the phase difference and the improvement of the power factor are dynamic processes that require real-time monitoring and adjustment.

[0072] The elevator energy feedback technology realizes the process of reducing the phase difference between the current and voltage and thus improving the power factor through power factor control of the power supply and sine wave PWM control.

[0073] In addition, the PWM frequency converter 4 also has the following functions:

[0074] 1) Speed control: The frequency converter can achieve stepless variable frequency speed regulation of the motor to meet the speed regulation requirements of the production process for the drive motor. By adjusting the frequency and voltage of the motor, the speed of the motor can be flexibly controlled according to actual needs, improving production efficiency and product quality.

[0075] 2) Energy saving and consumption reduction: The frequency converter precisely controls the operating speed of the motor to keep it at the best operating efficiency under different load conditions, thus reducing energy waste. For example, in loads such as fans and pumps, the frequency converter can usually achieve an energy-saving effect of 20% - 30%.

[0076] 3) Motor protection: The frequency converter has various protection functions, such as overcurrent, overvoltage, and overload protection, which can monitor the operating state of the motor, prevent problems such as equipment overload and overheating, and extend the service life of the equipment.

[0077] 4) Reducing grid impact: When starting and stopping the motor, the frequency converter can provide a smooth acceleration curve, reduce the impact on the grid, protect grid equipment, and improve the stability of the entire system.

[0078] 5) Other functions: The frequency converter also has functions such as noise reduction and vibration damping, increasing the motor life, smooth start and stop, and self-protection, which can improve the stability and reliability of the equipment.

[0079] The energy feedback converter 3 is used to convert DC electrical energy into AC electrical energy with the same frequency and phase as the grid voltage for feedback. Among them, during the elevator energy feedback process, when the traction machine is in the power generation state, the rectifier rectifies the DC electricity generated by the elevator traction machine and stores it in the capacitor. Then, the inverter in the energy feedback converter 3 converts the above DC electrical energy into AC electrical energy, and under the control of the PWM signal, adjusts the phase of the output current of the internal inverter switching device to make the phase difference with the grid voltage tend to become smaller, that is, to make its phase as consistent as possible with the grid voltage. The converted AC electrical energy is fed back to the grid for other equipment to use.

[0080] In an embodiment of the present invention, the switching device adopts multiple groups of IGBT units to form control loops S1 to S8.

[0081] The energy feedback converter 3 further includes: a controller, which monitors the grid voltage and current in real time, calculates the phase difference based on the monitored voltage and current signals, and adjusts the switching state of the switching device according to the phase difference to gradually reduce the phase difference.

[0082] To achieve power factor control of the power supply, it is necessary to monitor the phase difference between the grid voltage and current in real time. This is achieved through voltage and current sensors. The monitored voltage and current signals are sent to the controller for processing to calculate the phase difference, and the switching state of the inverter is adjusted according to the phase difference.

[0083] In the present invention, a closed-loop control system is adopted. This system monitors the phase difference between the grid voltage and current in real time and adjusts the switching state of the inverter according to the difference, thereby gradually reducing the phase difference.

[0084] In the closed-loop control system, a proportional-integral-derivative (PID) control algorithm is used to adjust the switching state of the inverter. The PID control algorithm includes parameters such as proportional gain (Kp), integral gain (Ki), and derivative gain (Kd). These parameters need to be adjusted according to the specific system characteristics to optimize the control performance.

[0085] Through power factor control of the power supply and sine wave PWM control, the present invention can make the phase difference between the current and voltage smaller, thereby improving the power factor and making the utilization of electric energy more efficient. In the optimal state, the power factor should be as close as possible. Through this design, the utilization of electric energy is made more efficient. The elevator energy feedback technology realizes the process of reducing the phase difference between the current and voltage through power factor control of the power supply and sine wave PWM control, thereby improving the power factor.

[0086] In addition, the controller is also used to monitor the operating state of the elevator and the power generation situation of the traction machine, and adjust the output power and recovery power of the converter according to the actual situation to ensure that the traction machine works in the optimal state.

[0087] Specifically, the intelligent control algorithm built into the controller can monitor the load change in real time and automatically adjust the output frequency and voltage to ensure that the motor (i.e., the traction machine) always works in the optimal state, reducing unnecessary power consumption. Through the analog output and communication network of the product, users can conveniently monitor key indicators such as power consumption, power saving, electricity cost, and power factor, helping users better understand the operating state of the equipment and optimize the operation.

[0088] Reference Figure 2, the energy feedback converter 3 further includes: multi-functional analog input terminals (A1, A2, A3), multi-functional opto-coupler output terminals (P1, P2), multi-functional analog monitoring output terminals (AM, FM), multi-functional contact output terminals (M1, M2), fault contact output terminals (MA, MB, MC), a shielding layer connection terminal E(G), and a toggle switch.

[0089] The working principle of the energy feedback converter 3 is described below: The electric energy generated by the elevator under specific working conditions is converted into an AC sine wave that is synchronized with the power grid and has the same phase, and then fed back to the power grid for other devices to use.

[0090] Specifically, when the elevator is in light-load upward or heavy-load downward working conditions, the traction machine will be in a power generation state and generate electric energy. In a traditional elevator system, this part of the electric energy is consumed in the form of heat through a braking resistor. However, the energy feedback converter 3 converts and processes this part of the electric energy through advanced power electronics technology.

[0091] First, the energy feedback converter 3 converts the DC electric energy generated by the traction machine into an AC sine wave that is synchronized with the power grid source and has the same phase. During this process, the energy feedback converter 3 will precisely control the switching devices inside it, such as IGBTs, etc., to adjust the phase and shape of the output current to ensure that its phase is consistent with the power grid voltage. Then, the converted AC electric energy will be fed back to the power grid for other nearby electrical equipment to use. This not only realizes the recycling of electric energy but also reduces the power consumption of the elevator system from the power grid, achieving the purpose of saving electric energy.

[0092] In addition, the energy feedback converter 3 will also perform real-time monitoring and control during operation to ensure the stable operation of the elevator and the efficient recovery of energy. For example, the control unit will monitor the operating state of the elevator and the power generation situation of the traction machine, and adjust the output power and recovery power of the converter according to the actual situation.

[0093] The MEMOBUS communication module 5 is connected to the energy feedback converter 3 for protocol conversion, output, and input. Refer to Figure 2 , the MEMOBUS communication module 5 uses RS485 and RS422 interfaces for signal transmission and is connected to the toggle switch.

[0094] Refer to Figure 3 , the frequency conversion energy-saving energy feedback device of the elevator equipment in the embodiment of the present invention can transfer electric energy between multiple elevators and supply multiple elevators simultaneously, such as 1 to 6 elevators. Through the frequency conversion energy-saving energy feedback device of the elevator equipment of the present invention, the statistics and billing of the saved electricity can be realized.

[0095] In summary, through the power regeneration technology, the present invention can recover and reuse the energy generated by the motor (i.e., the traction machine) during the braking process, thereby reducing the loss of energy in the form of heat and further achieving the energy-saving effect. Through the power factor control of the power supply and the sine wave PWM control, the present invention reduces the phase difference between the current and the voltage, thereby improving the power factor and making the utilization of electric energy more efficient. In the optimal state, the power factor should be as close as possible. Through this design, the utilization of electric energy is made more efficient.

[0096] In addition, high-order harmonics can cause energy waste and equipment heating, and even affect the stable operation of the power grid. By suppressing high-order harmonics, the present invention reduces the heat loss. Designed according to national and international standards, no additional harmonic suppression equipment is required, thereby saving equipment costs and reducing electricity bills.

[0097] Furthermore, the built-in controller of the present invention uses an intelligent control algorithm to be able to monitor the load change in real time and automatically adjust the output frequency and voltage to ensure that the motor (i.e., the traction machine) always operates in the optimal state, reducing unnecessary power consumption. Through the analog output and the communication network, users can conveniently monitor key indicators such as power consumption, power-saving amount, electricity bill, and power factor, helping users better understand the operating state of the equipment and optimize the operation.

[0098] In the description of this specification, the descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0099] It is not difficult for those skilled in the art to understand that the present invention includes any combination of the above-mentioned invention content and specific implementation parts of the specification and the parts shown in the drawings. Due to space limitations and to make the specification concise, the various solutions formed by these combinations are not described one by one. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0100] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, replacements, and variations to the above embodiments within the scope of the present invention without departing from the principle and purpose of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A variable frequency energy-saving energy feedback device for elevator equipment, characterized in that: include: High-order harmonic filter module, high-order harmonic filter reactor, energy feedback converter, PWM inverter and MEMOBUS communication module, among which, The high-order harmonic filtering module is used to filter out the high-order harmonics in the connected direct current to smooth the direct current voltage; One end of the high-order harmonic filter reactor is connected to the high-order harmonic filter module, and the other end is connected to the energy feedback converter. The high-order harmonic filter reactor is used to absorb and filter the high-order harmonic current in the power grid to avoid the occurrence of resonance; The PWM frequency converter is connected to the energy feedback converter and the traction machine, and is used to generate the switching signal required by the energy feedback converter, and to control the voltage and frequency of the AC power output by the energy feedback converter by adjusting the duty cycle and frequency of the PWM signal; The energy feedback converter is used to convert DC power into AC power with the same frequency and phase as the grid voltage for feedback. In the process of elevator energy feedback, when the traction machine is in the power generation state, the rectifier rectifies the generated DC power and stores it in the capacitor, and then the energy feedback converter converts the DC power into AC power, and adjusts the phase of the output current of the internal switching device under the control of the PWM signal so that the difference between the phase of the output current and the grid voltage tends to become smaller; the converted AC power is fed back to the grid for use by other equipment; The MEMOBUS communication module is connected to the energy feedback converter to realize protocol conversion, output and input.

2. The variable frequency energy-saving energy feedback device for elevator equipment according to claim 1 is characterized in that: The high-order harmonic filtering module includes a filter capacitor, which is connected to the high-order harmonic filtering reactor to perform reactive power compensation and filter out high-order harmonics.

3. The variable frequency energy-saving energy feedback device for elevator equipment according to claim 1, characterized in that: The PWM frequency converter adopts the sine wave pulse width modulation SPWM technology to generate a corresponding PWM signal according to the instantaneous value of the sine wave.

4. The variable frequency energy-saving energy feedback device for elevator equipment according to claim 1, characterized in that: The PWM signal output by the PWM frequency converter controls the switch device in the energy feedback converter, and adjusts the on and off time of the switch device to control the shape and phase of the output current.

5. The variable frequency energy-saving energy feedback device for elevator equipment according to claim 1, characterized in that: The energy feedback converter also includes: a controller, which monitors the grid voltage and current in real time, calculates the phase difference according to the monitored voltage and current signals, and adjusts the switching state of the switching device according to the phase difference to gradually reduce the phase difference.

6. The variable frequency energy-saving energy feedback device for elevator equipment according to claim 5, characterized in that: The controller is also used to monitor the running status of the elevator and the power generation status of the traction machine, and adjust the output power and recovery power of the converter according to the actual situation to ensure that the traction machine works in the optimal state.

7. The variable frequency energy-saving energy feedback device for elevator equipment according to claim 1, characterized in that: The switch device uses multiple groups of IGBT units to form a control loop.

8. The variable frequency energy-saving energy feedback device for elevator equipment according to claim 1, characterized in that: The energy feedback converter also includes: a multifunctional analog quantity input terminal, a multifunctional photoelectric coupler output terminal, a multifunctional analog quantity monitoring output terminal, a multifunctional contact output terminal, a fault contact output terminal, a shielding layer connection terminal and a toggle switch.

9. The variable frequency energy-saving energy feedback device for elevator equipment according to claim 8, characterized in that: The MEMOBUS communication module adopts RS485 and RS422 interfaces and is connected to the toggle switch.

10. The variable frequency energy-saving energy feedback device for elevator equipment according to claim 1, characterized in that: The variable frequency energy-saving energy feedback device of the elevator equipment is connected to a plurality of elevators to transmit electric energy to each other among the plurality of elevators.

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