CN100588075C - Hybrid energy storage device for elevator and control method thereof - Google Patents

Abstract

A hybrid energy storage device for an elevator and its control method, comprising a supercapacitor bank [10], a battery pack [20], a supercapacitor charging and discharging circuit [30], a battery charging and discharging circuit [40], and a supercapacitor charging and discharging control circuit [50], battery charge and discharge control circuit [60]. The supercapacitor bank [10] is connected with the DC bus in the elevator power supply system through the supercapacitor charging and discharging circuit [50], and the battery pack [20] is connected with the DC bus through the battery charging and discharging circuit [40]. The present invention can realize uninterrupted power supply and power buffering function by controlling the supercapacitor charging and discharging control circuit [50] and the storage battery charging and discharging control circuit [60]; the installation capacity of the supercapacitor group [10] and the storage battery group [20] is minimized The cost is saved; the battery pack [20] is in an optimized charging and discharging working state, the number of charging and discharging cycles is reduced, or the depth of discharge is reduced, and the service life is prolonged; the discharge circuit can be saved or its installation capacity can be reduced, saving space and reduce energy consumption. In the hybrid power supply device of the present invention, the battery pack [20] exchanges energy with the DC bus only through the first-stage DC/DC, and the energy storage efficiency is greatly improved.

Description

Hybrid energy storage device for elevator and control method thereof

technical field

The invention relates to a hybrid energy storage device and a control method thereof, in particular to a hybrid energy storage device for an elevator and a control method thereof.

Background technique

In the drive system of the elevator, the electric energy of the grid is generally directly rectified and confluent to the DC bus to form a DC power supply system, which is then inverted by a frequency converter to generate a three-phase alternating current with variable voltage and frequency to drive the motor. Since the motor will absorb a large amount of power from the DC bus when it starts or accelerates, the terminal voltage of the DC bus will decrease; and when it stops or decelerates, it will feed back power to the DC bus because the motor is in the power generation state, resulting in a rise in the bus voltage. high. If the DC bus voltage fluctuates too much, it will affect the working performance of the frequency converter and elevator auxiliary equipment in the system. In order to prevent the DC bus voltage from being too high, it is generally necessary to configure an energy discharge circuit, but it will cause a certain amount of energy loss and reduce the economy of the system.

In addition, when the power grid fails or an instantaneous voltage interruption or drop occurs, the elevator will not be able to operate normally without backup energy support, which will cause inconvenience and even danger to people, goods and devices. Equipped with energy storage devices, such as rechargeable batteries, supercapacitors, flywheel energy storage devices, etc., it can provide energy support for the DC bus for a certain period of time when the power grid fails or the voltage drops, so as to ensure that people and goods arrive at a safe location. In addition, the energy storage device can also play the role of power buffer. When the load power increases, the energy storage device outputs electric energy and provides the required power together with the grid to reduce the power demand of the grid; when the load generates power feedback, the energy storage device absorbs part of the power to avoid excessive bus voltage and also The discharge circuit can be saved or its installation capacity can be reduced.

Rechargeable batteries are a very common energy storage device, such as lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, etc. It is applied to the power supply system of the elevator, directly connected to the DC bus, or connected to the DC bus through a charging and discharging device, as an emergency power supply of the system, or a power buffer. US Patent US6457565B2 discloses an emergency power supply for elevators. After rectification and filtering, the power grid is connected to the DC bus, using a rechargeable battery as an energy storage device, and connected to the DC bus through a rechargeable/discharging bidirectional power converter. When the load is light, the DC bus passes through the power converter. Charge. When the bus voltage rises due to the electric energy feedback of the motor, the DC bus charges the battery through the power converter, and releases it when the load is heavy to play the role of power buffer. When the power grid fails, or the voltage is interrupted or dropped, the battery releases energy through the power converter to maintain the DC bus voltage within the normal range and ensure the normal operation of the system.

There are certain deficiencies in applying the rechargeable storage battery to the power supply system of the elevator. First of all, during the working process of the battery, the electrode active material will undergo chemical changes, which will cause the expansion and contraction of the electrode structure, resulting in the performance degradation of the battery. In the power supply system of the elevator, since the battery needs to absorb and release energy continuously, in areas where the grid power supply is unreliable, deep charging and discharging must be carried out frequently to ensure uninterrupted power supply, resulting in shortened service life of the battery, which needs to be replaced frequently, increasing cost of the system. Secondly, the recovery time of the capacity of the battery after discharge is relatively long. After the power grid is restored, due to the large discharge depth of the battery, it usually takes a long time to restore the capacity to a certain level, resulting in a long time for the elevator to recover after a power outage. recovery time to operate safely again. Thirdly, the power density of the battery is small, while the power of the elevator is relatively large. In order to ensure the normal operation of the system when the power grid is out of power, the battery needs to output a large power. Therefore, in the actual design, it is necessary to configure a battery pack with a large capacity, which increases the cost of the system and reduces the economy. In addition, the charging and discharging efficiency of the battery is low, requiring frequent maintenance, and the metal materials after use are not easy to handle, which will cause environmental pollution.

Supercapacitor is a new type of energy storage device that has emerged in recent years. At present, it is generally believed that supercapacitors include two types: Electric Double Layer Capacitor (Electric Double Layer Capacitor) and Electrochemical Capacitor (Electrochemical Capacitor). Among them, the electric double layer capacitor uses activated carbon with high specific surface area, and works based on the separation of charges on the interface between the carbon electrode and the electrolyte to generate an electric double layer capacitance. Electrochemical capacitors use noble metal oxides such as RuO ₂ as electrodes, and oxidation-reduction reactions occur on the surface and bulk phase of oxide electrodes to generate adsorption capacitance, also known as Faraday quasi-capacitance, which can be divided into metal oxides and conductive capacitors according to different electrode materials. Two types of electrochemical capacitors based on permanent polymers. Since the generation mechanism of Faraday quasi-capacitance is similar to that of batteries, its capacitance is several times that of electric double layer capacitors under the same electrode area; but the power characteristics of instantaneous large current discharge of electric double layer capacitors are better than those of Faraday capacitors.

Supercapacitors have good power characteristics and can be charged and discharged quickly with high current and high efficiency. Since the charging and discharging process is always a physical process, there is no electrochemical reaction and no change in the electrode structure, so its cycle life is long. In addition, supercapacitors also have many advantages such as good high and low temperature performance, simple and accurate energy judgment, no maintenance, and environmental friendliness, and are increasingly becoming an efficient and practical energy storage device.

US Patent US6938733B2 discloses an elevator emergency power supply device, in which a supercapacitor bank is connected to a DC bus through a power regulating device. When the power grid fails, the voltage drops or is interrupted, the supercapacitor bank supplies power to the DC bus through the power conditioning equipment to maintain the normal operation of the motor and elevator auxiliary equipment until reaching the next floor. The supercapacitor bank can also continuously absorb or release energy through the power regulation equipment, and act as a power buffer to ensure that the DC bus voltage is stable and within the normal range.

Although supercapacitors have many advantages, their energy density is lower than that of rechargeable batteries. At present, the energy density of supercapacitors is about 20% of that of valve-regulated lead-acid batteries, and they are not suitable for large-capacity electric energy storage. Due to the high power and long duration of the elevator, if a supercapacitor is used as an emergency power supply, a supercapacitor bank with a large capacity needs to be configured to output the required energy, which will make the equipment too bulky and cumbersome. Moreover, the price of supercapacitors is relatively high at present, and the configuration of such a large capacity greatly increases the cost of the system and reduces the economy.

If supercapacitors are used in combination with rechargeable batteries, combining the high energy density of batteries with the characteristics of high power density and long cycle life of supercapacitors will undoubtedly bring great performance improvements to electric energy storage devices. The supercapacitor-battery hybrid energy storage device has good energy storage capacity and power input and output capacity, can reduce the volume of the energy storage device, and improve reliability. The battery works in parallel with the supercapacitor in a certain way, which can optimize the charging and discharging process of the battery, reduce the number of charging and discharging cycles, reduce internal loss, increase the discharge time, and prolong the service life. The use of supercapacitor battery energy storage devices can greatly improve the technical performance and economic performance of the system, and it is a good choice to solve the current power energy storage problems. In the elevator emergency power supply device disclosed in U.S. Patent US6938733B2, in order to prolong the discharge time of the emergency power supply, the patent proposes a design method using a combination of a rechargeable battery and a supercapacitor, but does not provide a specific combination of the two energy storage devices and energy management methods.

Contents of the invention

The purpose of the present invention is to provide a hybrid energy storage device for elevators and its control method, which can provide emergency power supply for power grid failure or voltage drop or interruption; and can provide power for bus voltage fluctuations caused by changes in motor working conditions. Power buffering to maintain the bus voltage stability to save the discharge circuit or reduce its installation capacity.

The hybrid energy storage device of the present invention is composed of a supercapacitor group, a storage battery group, a supercapacitor charging and discharging circuit, a storage battery charging and discharging circuit, a supercapacitor charging and discharging control circuit, and a storage battery charging and discharging control circuit. The supercapacitor bank is connected to the DC bus through the supercapacitor charge and discharge circuit, and the battery pack is connected to the DC bus through the battery charge and discharge circuit. The supercapacitor charge and discharge control circuit controls the operation of the supercapacitor charge and discharge circuit, and the battery charge and discharge control circuit controls the battery charge and discharge. circuit work.

Supercapacitors can be electric double layer capacitors or electrochemical capacitors. Single supercapacitors are first connected in series to form a series branch, and then two or more series branches are connected in parallel to form a supercapacitor bank. The specific series-parallel combination scheme depends on the actual situation of the system. In order to improve the capacity utilization rate of the supercapacitor bank and limit the single voltage below the maximum working voltage, the supercapacitor bank can use a series voltage equalizer or a series-parallel conversion circuit. The battery pack also consists of a number of single cells connected in series to form a series branch, and then two or more series branches are connected in parallel to form a battery pack. The specific series-parallel combination scheme depends on the actual situation of the system.

Supercapacitor charging and discharging circuits and battery charging and discharging circuits generally use non-isolated DC/DC power converters. Since energy flows bidirectionally during actual work, they should be designed as bidirectional DC/DC. The bidirectional DC/DC used in the present invention is actually composed of a step-down BUCK circuit and a step-up BOOST circuit. The two circuits share an inductor, and each circuit has a pair of power switches and power diodes. When one circuit is working, the pair of power switches and power diodes of the other circuit is always inactive, and vice versa. The two circuits work alternately in different time periods to form a bidirectional DC/DC.

The supercapacitor charge and discharge control circuit and the battery charge and discharge control circuit mainly include signal sampling unit, A/D conversion unit, user command unit, calculation control unit (CPU), isolation drive unit, etc. The specific control and management process is realized by software.

The signal sampling unit detects the state parameters of the system, including battery voltage, temperature, electrolyte density, charge and discharge current, etc.; supercapacitor voltage, charge and discharge current, etc.; DC bus voltage and its change process; elevator position, load capacity , speed, acceleration, etc.; and grid voltage, voltage interruption or drop degree, etc. The system samples these parameters through the signal sampling unit, generates the corresponding voltage signal, and sends it to the A/D conversion unit, and the A/D conversion unit sends the converted digital signal to the calculation control unit as the entry parameter of the system control.

The user instruction unit accepts user instructions, including elevator lift, destination floor, etc., and sends these instructions to the calculation control unit as entry parameters for system control.

The hybrid energy storage device and its control method of the present invention, on the premise of realizing system functions, strive for high efficiency and energy saving, and can reduce the installation capacity of the energy storage device, prolong the service life of the storage battery, and improve the economy. The basic principles of its control thoughts include the following points.

First, give full play to the variable current control function of the battery charging and discharging circuit and the supercapacitor charging and discharging circuit, and rationally configure the capacity of the battery pack and the supercapacitor pack to meet the larger power and energy demands with a smaller capacity and reduce the storage capacity. installation cost of the device.

Second, the energy exchange between the DC bus and the hybrid energy storage device occurs as much as possible on the supercapacitor and as little as possible on the battery, so as to fully utilize the high power density, long cycle life, and The advantages of high charging and discharging efficiency and fast speed.

Third, control the charging and discharging circuit of the battery, optimize the charging and discharging process of the battery, reduce the number of charging and discharging cycles and small cycles, or reduce the depth of discharge to prolong the service life.

Fourth, according to the system information such as the state of the power grid, the state of charge of the energy storage device, the state of the elevator, and user instructions, the power and energy that the hybrid energy storage device needs to output or input are judged in advance, and the supercapacitor bank and the battery are controlled in a timely and accurate manner. The working process of the group improves the rapid response capability of the energy storage device.

The working process of the present invention is to charge the supercapacitor bank and the storage battery bank in a certain way before the elevator starts to run, so that they are in a certain state of charge. Use a larger current to charge the supercapacitor bank, and charge the battery pack with an optimized charging method, such as constant current charging or pulse charging.

When the elevator starts and accelerates, it absorbs a large amount of power from the DC bus through the frequency converter, causing the voltage of the bus to drop. When the grid voltage is interrupted or dropped for a short time, the voltage of the bus will also drop. When the bus voltage is lower than a certain set value, the supercapacitor bank supplies power to the DC bus through the charging and discharging circuit, and the output power depends on the change rate of the bus power to maintain the bus voltage within a certain range. In general, the peak power demand of the system can be met only through the supercapacitor bank, but when the terminal voltage of the supercapacitor bank is lower than a certain set value due to discharge, or it is judged according to the system status and user instructions that the battery pack needs to be released When the power and energy are certain, the battery pack is discharged at a constant current through the battery charging and discharging circuit, and supplies power to the DC bus together with the supercapacitor bank.

When the motor regenerates energy, the voltage of the DC bus will increase. When it is higher than a certain set value, the DC bus charges the supercapacitor bank through the supercapacitor charging and discharging circuit, and the charging power depends on the power change rate of the busbar. Under normal circumstances, only charging the supercapacitor bank can achieve the purpose of absorbing the peak power, but when the terminal voltage of the supercapacitor bank is higher than a certain set value, or it is judged according to the system status and user instructions that the battery bank needs to absorb a certain amount of power. In terms of power and energy, the DC bus charges the battery pack through the battery charging and discharging circuit, and generally adopts a more optimized constant current charging method.

When the power grid fails, the hybrid energy storage device needs to provide a certain amount of power and energy to the DC bus to ensure that the backup power generation system can reliably start and output electric energy, or ensure that the electrical equipment can be shut down safely, or continue to run until the grid returns to normal power supply. In the process of emergency power supply, control the charging and discharging circuit of the battery, so that the battery pack is discharged in a constant current mode, and the output power is equal to the average power of the elevator; control the charging and discharging circuit of the supercapacitor, so that the supercapacitor bank provides the peak power of the elevator during work .

In high-rise sightseeing towers or mines, the elevator or mine hoist travels a long distance due to few stops, and the auxiliary power supply needs to support for a long time until the elevator reaches the stop and opens the door. There are also some special applications that require the elevator to continue to run for several hours after a power outage. The hybrid energy storage device can make full use of the advantages of high energy density of the battery, control the charging and discharging circuit of the battery, and make the battery pack discharge in an optimized constant current mode.

When the power grid returns to normal, in order to ensure safe work (there may be a short interval between two power outages), the elevator cannot work immediately, but the hybrid energy storage device needs to be charged in a certain way. Use a larger current to charge the supercapacitor bank, and use an optimized charging method to charge the battery pack. When the state of charge of the storage battery pack and the supercapacitor pack reaches the set value, the elevator can work again.

The invention adopts supercapacitor-battery hybrid energy storage, and is equipped with an effective control method, which has the following advantages:

(1) The hybrid energy storage of super capacitor and battery can give full play to the advantages of high energy density of battery and high power density of super capacitor, long cycle life, fast charge and discharge speed and high energy storage efficiency, so that the energy storage device has good technical performance.

(2) Due to the battery charging and discharging circuit and its control circuit, the charging and discharging process of the battery can be optimized, the number of small charging and discharging cycles can be reduced, or the discharge depth when a small cycle occurs, and the service life can be extended.

(3) Due to the supercapacitor charging and discharging circuit and its control ability, the terminal voltage of the supercapacitor bank can be very different from the DC bus voltage. Under the premise of meeting the same power demand, the energy utilization rate of the supercapacitor is greatly improved. Reduced installation capacity and reduced system costs.

(4) Due to the variable flow effect of the battery charging and discharging circuit and the supercapacitor charging and discharging circuit, the terminal voltage of the battery pack, the terminal voltage of the supercapacitor bank, and the terminal voltage of the DC bus can be very different, so that the supercapacitor The structure configuration of battery pack and storage battery pack is more flexible.

(5) When the motor generates energy feedback, through the control of the supercapacitor charging and discharging circuit, the instantaneous high power on the DC bus can be effectively absorbed, and the discharge circuit is not required, or the installation of the discharge circuit can be greatly reduced capacity, reducing power consumption and saving costs.

(6) The battery pack only exchanges energy with the DC bus through the first-stage DC/DC power converter, which reduces energy loss and improves energy storage efficiency.

The invention mixes the supercapacitor and the rechargeable storage battery, combines the characteristics of high energy density of the storage battery with the high power density and long cycle life of the supercapacitor, and improves the performance of the electric energy storage device. The supercapacitor-battery hybrid energy storage device has good energy storage capacity and power input and output capacity, can reduce the volume of the energy storage device, and improve reliability. The battery works in parallel with the supercapacitor in a certain way, which can optimize the charging and discharging process of the battery, reduce the number of charging and discharging cycles, reduce internal loss, increase the discharge time, and prolong the service life. The use of supercapacitor battery energy storage devices can greatly improve the technical performance and economic performance of the system. It is a good choice to solve the current power energy storage problem. Using it in elevators has obvious advantages.

Description of drawings

Fig. 1 is a block diagram of the working principle of the hybrid energy storage device of the present invention applied to the elevator power supply system;

Fig. 2 is the schematic diagram of the bidirectional DC/DC converter of the supercapacitor charging and discharging circuit of the present invention;

Fig. 3 is the schematic diagram of the bidirectional DC/DC converter of the storage battery charging and discharging circuit of the present invention;

Fig. 4 is the functional block diagram of supercapacitor charging and discharging control circuit of the present invention;

Fig. 5 is a functional block diagram of the battery charging and discharging control circuit of the present invention;

Fig. 6 is a flow chart of the pre-charging control of the hybrid energy storage device of the present invention before the elevator runs;

Fig. 7 is a control flow chart of the hybrid energy storage device of the present invention when the bus voltage drops;

Fig. 8 is a control flow chart of the hybrid energy storage device of the present invention when the load generates energy feedback;

Fig. 9 is a control flow chart of the hybrid energy storage device of the present invention when the grid is powered off;

Fig. 10 is a working principle block diagram of the hybrid energy storage device of the present invention applied to a multi-elevator power supply system.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

As shown in FIG. 1 , the elevator device of the present invention includes a rectifier 200 , a DC bus 11 , a bus filter capacitor 300 , a discharge circuit 100 , a frequency converter 901 , a motor and its load 902 . Wherein, the bleed circuit 100 is connected in parallel with the DC bus 11 , and includes a bleed resistor 101 and a bleed control switch 102 . The three-phase AC power of the power grid is rectified by the rectifier 200, and the output is supplied to the DC bus 11. The bus filter capacitor 300 filters the DC bus 11. The input terminal of the frequency converter 901 is connected to the DC bus 11, and the output three-phase AC drives the motor and its load 902 .

The hybrid energy storage device for elevators of the present invention includes a supercapacitor bank 10, a battery pack 20, a supercapacitor charging and discharging circuit 30, a battery charging and discharging circuit 40, a supercapacitor charging and discharging control circuit 50, and a battery charging and discharging control circuit 60. The supercapacitor bank 10 is connected to the DC bus 11 through the supercapacitor charging and discharging circuit 30 , and the battery pack 20 is connected to the DC bus 11 through the battery charging and discharging circuit 40 . The supercapacitor charging and discharging control circuit 50 controls the operation of the supercapacitor charging and discharging circuit 30 to determine the energy flow process between the supercapacitor bank 10 and the DC bus 11 . Before the elevator starts to work, the DC bus 11 charges the supercapacitor bank 10 with a relatively large power through the supercapacitor charging and discharging circuit 30 until the state of charge of the supercapacitor bank 10 reaches a set value. The battery charge and discharge control circuit 60 controls the operation of the battery charge and discharge circuit 40 to determine the energy flow process between the battery pack 20 and the DC bus 11 . Before the elevator starts to work, the DC bus 11 charges the battery pack 20 in an optimized constant current or pulse mode through the battery charging and discharging circuit 40 until its state of charge reaches a set value. During the working process, the working process of the storage battery pack 20 is determined according to the system status and user instructions. When the battery pack 20 needs to provide a certain amount of energy within a specific time, the battery charging and discharging circuit 40 is controlled so that the battery pack 20 is discharged in an optimized constant current manner. When the battery pack 20 needs to absorb a certain amount of energy within a specific time, the battery charging and discharging circuit 40 is controlled to charge the battery pack 20 in an optimized constant current or pulse mode.

FIG. 2 shows the bidirectional DC/DC converter of the supercapacitor charging and discharging circuit 30 of the present invention. It is composed of controllable power switch tubes 32, 34, power diodes 33, 35, inductor 31, filter capacitors 36, 37, and ports 38, 39. One end 31a of the inductance 31 is connected to the positive end 38a of the port 38; the other end 31b of the inductance 31 is connected to the collector 32a of the power switch tube 32, and is connected to the cathode 33a of the power diode 33, and the emitter 32b of the power switch tube 32 is connected to the The anode 33b of the diode 33 is connected to the negative terminal 38b of the port 38 and the negative terminal 39b of the port 39; , the collector 34b of the power switch tube 34 is connected to the cathode 35b of the diode 35, and is connected to the positive terminal 39a of the port 39; the filter capacitor 36 is connected in parallel to the port 38, and the filter capacitor 37 is connected in parallel to the port 39. Among them, the controllable power switch tubes 32 and 34 include but are not limited to MOSFET, IGBT, IGCT, etc. This embodiment adopts an IPM module that integrates the IGBT power switch device and its driving circuit. Protective function. When the port 38 is used as the input terminal and the port 39 is used as the output terminal, the circuit is a step-up DC/DC, the power switch tube 34 and the diode 33 do not work, and the power switch tube 32 is used as a controllable switch tube to control the circuit together with the diode 35 Work. When the port 39 is used as the input terminal and the port 38 is used as the output terminal, the circuit is a step-down DC/DC, the power switch tube 32 and the power diode 35 do not work, and the power switch tube 34 is used as a controllable switch tube, controlled together with the power diode 33 circuit work. Since the voltage of the DC bus 11 is relatively high, the port 38 is connected to the supercapacitor bank 10 , and the port 39 is connected to the DC bus 11 . When the energy flows from the supercapacitor bank 10 to the DC bus 11 , it is a step-up DC/DC, and when the energy flows from the DC bus 11 to the supercapacitor bank 10 , it is a step-down DC/DC.

FIG. 3 shows the bidirectional DC/DC converter of the storage battery charging and discharging circuit 40 of the present invention. It is composed of controllable power switch tubes 42, 44, power diodes 43, 45, inductor 41, filter capacitors 46, 47, and ports 48, 49. One end 41a of the inductance 41 is connected to the positive end 48a of the port 48; the other end 41b of the inductance 41 is connected to the collector 42a of the power switch tube 42, and is connected to the cathode 43a of the power diode 43, and the emitter 42b of the power switch tube 42 is connected to the The anode 43b of the diode 43 is connected to the negative end 48b of the port 48 and the negative end 49b of the port 49; the other end 41b of the inductor 41 is connected to the emitter 44a of the power switch tube 44 and connected to the anode 45a of the power diode 45 , the collector 44b of the power switching tube 44 is connected to the cathode 45b of the diode 45, and is connected to the positive terminal 49a of the port 49; the filter capacitor 46 is connected in parallel to the port 48, and the filter capacitor 47 is connected in parallel to the port 49. Among them, the controllable power switch tubes 42 and 44 include but are not limited to MOSFET, IGBT, IGCT, etc. This embodiment adopts an IPM module that integrates the IGBT power switch device and its driving circuit. Protective function. Since the voltage of the DC bus 11 is relatively high, the port 48 is connected to the battery pack 20 and the port 49 is connected to the DC bus 11 . In this way, when the energy flows from the battery pack 20 to the DC bus 11 , it is a step-up DC/DC, and when the energy flows from the DC bus 11 to the battery pack 20 , it is a step-down DC/DC.

As shown in FIG. 4 , the supercapacitor charge and discharge control circuit 50 of the present invention includes a signal sampling unit 51 , an A/D conversion unit 52 , a user command unit 53 , a calculation control unit 54 , and an isolation drive unit 55 . Wherein, the computing control unit 54 includes but is not limited to a digital signal processor DSP, a single-chip microcomputer, an embedded system, and the like. The signal sampling unit 51 uses voltage sensors, current sensors, temperature sensors, speed sensors, acceleration sensors, position sensors, concentration sensors, and load cells to sample the state parameters of the system, including grid voltage, bus voltage, elevator position, Load capacity, speed and acceleration, voltage and charge and discharge current of the supercapacitor bank 10, voltage, temperature, electrolyte density and charge and discharge current of the battery pack 20. The output voltage signal is sent to the A/D conversion unit 52 , and the converted digital signal is sent to the calculation control unit 54 . The user command unit 53 sends the user command to the computing control unit 54, including the lifting and lowering of the elevator and the destination floor. The calculation control unit 54 outputs control signals according to the set control process, and drives the power switch tubes 32 and 34 in the supercapacitor charging and discharging circuit 30 through the isolation drive unit 55 to realize the control process. The set control process includes: before the elevator runs, control the power switch tube 32 to cut off, drive the power switch tube 34, and the DC bus 11 supplies power to the supercapacitor bank 10; ] cut off, drive the power switch tube 32, and the supercapacitor bank 10 provides energy to the DC bus bar 11; in the process of energy feedback generated by the elevator, control the switch tube 32 to cut off, drive the power switch tube 34, and the DC bus bar 11 supplies power to the supercapacitor bank 10; During the grid power outage, the power switch tube 34 is controlled to be cut off, the power switch tube 32 is driven, and the supercapacitor bank 10 supplies energy to the DC bus 11 .

As shown in FIG. 5 , the battery charge and discharge control circuit 60 of the present invention includes a signal sampling unit 61 , an A/D conversion unit 62 , a user command unit 63 , a calculation control unit 64 , and an isolation drive unit 65 . Wherein, the computing control unit 54 includes but is not limited to a digital signal processor DSP, a single-chip microcomputer, an embedded system, and the like. The signal sampling unit 61 uses voltage sensors, current sensors, temperature sensors, speed sensors, acceleration sensors, position sensors, concentration sensors, and load cells to sample the state parameters of the system, including grid voltage, bus voltage, elevator position, Load capacity, speed and acceleration, voltage and charge and discharge current of the supercapacitor bank 10, voltage, temperature, electrolyte density and charge and discharge current of the battery pack 20, etc. The output voltage signal is sent to the A/D conversion unit 62 , and the converted digital signal is sent to the calculation control unit 64 . The user instruction unit 63 sends user instructions to the computing control unit 64, including elevator lift, destination floor and so on. The calculation control unit 64 outputs control signals according to the set control process, and drives the power switch tubes 42 and 44 in the battery charging and discharging circuit 40 through the isolation drive unit 65 to realize the control process. The set control process includes: before the elevator runs, control the power switch tube 42 to cut off, drive the power switch tube 44, and the DC bus 11 supplies power to the storage battery pack 20; When the voltage drops to a certain set value, the power switch tube 44 is controlled to be cut off, and the power switch tube 42 is driven to provide energy to the DC bus 11; When the value is fixed, the power switch tube 42 is controlled to cut off, the power switch tube 44 is driven, and the DC bus 11 supplies power to the storage battery pack 20; Energy, whose output power is equal to the average power of the elevator during work.

In practical applications, the supercapacitor charge and discharge control circuit 50 and the battery charge and discharge control circuit 60 share a signal acquisition unit, an A/D conversion unit, and a user command unit, and the calculation control unit may use one CPU or multiple CPUs. There are data communication channels between multiple CPUs.

Before the elevator starts running, the grid supplies power to the DC bus 11 through the rectifier 200 to establish a working voltage for it. The hybrid energy storage device starts precharging, and the charging process is shown in Figure 6. According to the system status and user instructions, including the elevator position, load capacity, lifting distance, etc., the state of charge that the storage battery pack 20 and the supercapacitor pack 10 should reach is determined. The DC bus 11 charges the supercapacitor bank 10 through the supercapacitor charging and discharging circuit 30, and the charging power is relatively large, so that its state of charge can quickly reach the set requirement. During this working process, the power switch tube 32 is always turned off, and the driving signal output by the supercapacitor charging and discharging control circuit 50 controls the switch tube 34 to control the power supply process from the DC bus 11 to the supercapacitor bank 10 . At the same time, the DC bus 11 charges the battery pack 20 through the battery charging and discharging circuit 40 , using an optimized constant current charging or pulse charging method. During this working process, the power switch tube 42 is always disconnected, and the battery charging and discharging control circuit 60 outputs a driving signal to control the switch tube 44 to control the power supply process of the DC bus 11 to the battery pack 20 . When the state of charge of the supercapacitor bank 10 and the storage battery pack 20 reaches the set value, the charging is stopped, and the elevator is ready to run.

During the start-up and acceleration process of the elevator, the power demand increases, which causes the voltage of the DC bus 11 to drop; in addition, when the grid voltage is interrupted or dropped, the bus voltage will also drop. The hybrid energy storage device supplies power to the DC bus 11 to maintain its voltage within a certain range. The process is shown in FIG. 7 . The supercapacitor bank 10 supplies power to the DC bus 11 through the supercapacitor charging and discharging circuit 30 . During this process, the power switch tube 34 is always turned off, and the control signal output by the supercapacitor charging and discharging control circuit 50 drives the power switch tube 32 to control the power supply process of the supercapacitor bank 10 to the DC bus 11 . Under normal circumstances, only the discharge of the supercapacitor bank 10 can meet the system requirements, but when the supercapacitor bank 10 continues to discharge and its terminal voltage drops to a certain set value, or it is judged based on the system status and user instructions that the battery pack 20 needs to release a certain amount of power and energy, the battery pack 20 supplies power to the DC bus 11 through the battery charging and discharging circuit 40 . During this process, the power switch tube 44 is always disconnected, and the drive signal output by the battery charging and discharging control circuit 60 controls the power switch tube 42 to control the power supply process of the battery pack 20 to the DC bus 11 . The battery pack 20 generally works in an optimized constant current discharge mode. Detect the state of charge of the supercapacitor bank 10 and the battery pack 20, if it is lower than a certain set value, control the elevator to stop safely, and the hybrid energy storage device stops power supply.

During the process of deceleration and stop of the elevator, the motor is in the state of generating power, and feeds power to the DC bus 11 through the frequency converter 901, causing the voltage of the bus to rise. The hybrid energy storage device absorbs this part of power and energy in a certain way, and the process is shown in Figure 8. The supercapacitor charging and discharging control circuit 50 controls the supercapacitor charging and discharging circuit 30 so that the DC bus 11 charges the supercapacitor bank 10 through the supercapacitor charging and discharging circuit 30 . During this working process, the power switch tube 32 is always turned off, and the driving signal output by the supercapacitor charge and discharge control circuit 60 controls the switch tube 34 to control the power supply process from the DC bus 11 to the supercapacitor bank 10 . Under normal circumstances, only charging the supercapacitor bank 10 can achieve the purpose of absorbing the peak power, but when the supercapacitor bank 10 is continuously charged to cause its terminal voltage to rise to a certain set value, or judged by the system status and user instructions When the battery pack 20 needs to absorb a part of power or energy, the battery charging and discharging control circuit 60 controls the battery charging and discharging circuit 40 , and the DC bus 11 charges the battery pack 20 through the battery charging and discharging circuit 40 . During this process, the power switch tube 42 is always disconnected, and the drive signal output by the battery charging and discharging control circuit 60 controls the power switch tube 44 to control the power supply process from the DC bus 11 to the battery pack 20 . Generally, the battery pack 20 works in an optimized constant current charging mode. When the supercapacitor bank 10 and battery pack 20 are charged to the set state of charge and the terminal voltage of the DC bus 11 is still higher than the set voltage value, the control switch 102 in the discharge circuit 100 is closed, and the DC bus 11 is discharged through The resistor 101 is discharged until the terminal voltage of the DC bus 11 drops to a set voltage value, and the control switch 102 is turned off.

When the power grid fails, the hybrid energy storage device provides the power and energy required for the normal operation of the elevator to achieve uninterrupted power supply. The process is shown in Figure 9. The battery pack 20 supplies power to the DC bus 11 through the battery charging and discharging circuit 40, and the battery pack 20 discharges at a constant current, and its output power is equal to the average power during the running of the elevator. During this process, the power switch tube 44 is always disconnected, and the drive signal output by the battery charging and discharging control circuit 60 controls the power switch tube 42 to control the power supply process of the battery pack 20 to the DC bus 11 . The supercapacitor bank 10 supplies power to the DC bus 11 through the supercapacitor charging and discharging circuit 30, and is mainly used to provide the peak power demand of the elevator when starting and accelerating, and to accept the charging of the DC bus 11 when the power demand of the elevator is low, such as decelerating and stopping. . During this process, the driving signal output by the supercapacitor charge and discharge control circuit 50 controls the power switch tubes 32 and 34 to work alternately in different time periods, so as to realize the bidirectional flow of energy. The hybrid energy storage device continues to work until the elevator continues to run to the next floor and the elevator door is opened, or other backup power generation equipment starts and outputs electricity, or continues to run until the grid restores power. If the power failure time is too long and the state of charge of the battery pack 20 and the supercapacitor pack 10 is lower than the set lower limit, the system controls the elevator to stop safely at an appropriate floor and stops the power supply of the hybrid energy storage device.

Fig. 10 is an application example of the hybrid energy storage device of the present invention in a multi-elevator power supply system. On the basis of the system shown in Figure 1, the power grid is rectified by the rectifier circuit 200 and the generated DC power is transmitted to the DC bus 11, and the DC bus 11 drives multiple groups of loads 90 composed of frequency converters 901 and motors 902. In this embodiment , all elevator devices share a set of discharge circuit 100 (including discharge discharge group 101 and discharge control switch 102 ) through DC bus 11 .

The working process and control method of the hybrid energy storage device are similar to the embodiment shown in FIG. 1 . The advantage of this embodiment is that, by driving multiple sets of loads 90 through one set of DC bus bars 11, the energy complementarity between the loads due to the asynchronous working process can be fully utilized, so that the installation capacity of the hybrid energy storage device can be further reduced. The working process of the supercapacitor pack 10 and the storage battery pack 20 is reduced, and the energy utilization efficiency is improved.

Claims (7)

1. A hybrid energy storage device for an elevator, characterized in that it comprises a supercapacitor bank [10], a battery pack [20], a supercapacitor charging and discharging circuit [30], a battery charging and discharging circuit [40], a supercapacitor charging and discharging circuit [40], and a supercapacitor charging and discharging circuit [40]. Control circuit [50], storage battery charge and discharge control circuit [60]; supercapacitor bank [10] is connected with DC bus [11] through supercapacitor charge and discharge circuit [30], battery pack [20] is connected through battery charge and discharge circuit [40] ] is connected with the DC bus [11]; the supercapacitor charging and discharging control circuit [50] controls the working process of the supercapacitor charging and discharging circuit [30], and the battery charging and discharging control circuit [60] controls the working process of the battery charging and discharging circuit [40] ; The supercapacitor charging and discharging circuit [30] and the battery charging and discharging circuit [40] adopt non-isolated bidirectional DC/DC power converters; the supercapacitor charging and discharging control circuit [50] includes a signal sampling unit [51], A/D conversion Unit [52], user command unit [53], calculation control unit [54], and isolation drive unit [55]; battery charge and discharge control circuit [60] includes signal sampling unit [61], A/D conversion unit [62] ], user command unit [63], calculation control unit [64], and isolation drive unit [65]; In the supercapacitor charging and discharging control circuit [50], the signal sampling unit [51] collects the state parameters of the power grid, the DC bus [11], the elevator, the supercapacitor bank [10] and the battery pack [20], and the output voltage signal is sent to The A/D conversion unit [52], the A/D conversion unit [52] sends the converted digital signal to the calculation control unit [54], the user instruction unit [53] sends the user instruction to the calculation control unit [54], and the calculation The output control signal of the control unit [54] is sent to the isolation drive unit [55]; in the battery charging and discharging control circuit [60], the signal sampling unit [61] collects the power grid, DC bus [11], elevator, supercapacitor bank [10] ] and the state parameters of the battery pack [20], the output voltage signal is sent to the A/D conversion unit [62], and the A/D conversion unit [62] sends the converted digital signal to the calculation control unit [64], and the user command unit [63] Send user instructions to the calculation control unit [64], and the calculation control unit [64] outputs control signals to the isolation drive unit [65]. 2. The hybrid energy storage device for elevators according to claim 1, characterized in that: the bidirectional DC/DC power converter of the supercapacitor charging and discharging circuit [30] is composed of first and second controllable power switch tubes [32, 34], first and second power diodes [33, 35], first inductor [31], first and second filter capacitors [36, 37], first and second ports [38, 39]; One end [31a] of an inductance [31] is connected to the positive end [38a] of the first port [38]; the other end [31b] of the first inductance [31] is connected to the set of the first controllable power switch tube [32] The electrode [32a] is connected with the cathode [33a] of the first power diode [33], the emitter [32b] of the first controllable power switch tube [32] is connected with the anode [33b] of the first power diode [33], And connected with the negative end [38b] of the first port [38] and the negative end [39b] of the second port [39]; the other end [31b] of the first inductance [31] is connected with the second controllable power switch tube [ The emitter [34a] of 34] is connected with the anode [35a] of the second power diode [35], and the collector [34b] of the second controllable power switch tube [34] is connected with the cathode [35] of the second power diode [35]. 35b], and connected to the positive terminal [39a] of the second port [39]; the first filter capacitor [36] is connected in parallel with the first port [38], and the second filter capacitor [37] is connected to the second port [39] ] are connected in parallel, the first port [38] is connected with the supercapacitor bank [10], and the second port [39] is connected with the DC bus [11]. 3. The hybrid energy storage device for elevators according to claim 2, characterized in that: the bidirectional DC/DC power converter of the battery charging and discharging circuit [40] is composed of third and fourth controllable power switch tubes [42, 44 ], the third and fourth power diodes [43, 45], the second inductance [41], the third and fourth filter capacitors [46, 47], the third and fourth ports [48, 49]; the second One end [41a] of the inductance [41] is connected to the positive end [48a] of the third port [48]; the other end [41b] of the second inductance is connected to the collector [42a] of the third controllable power switch tube [42] It is connected with the cathode [43a] of the third power diode [43], the emitter [42b] of the third controllable power switch tube [42] is connected with the anode [43b] of the third power diode [43], and is connected with the third The negative end [48b] of port [48] and the negative end [49b] of the fourth port [49] are connected; the other end [41b] of the second inductance [41] is connected to the emission of the fourth controllable power switch tube [44] pole [44a] and the anode [45a] of the fourth power diode [45] are connected, the collector [44b] of the fourth controllable power switch tube [44] is connected with the cathode [45b] of the fourth power diode [45], And connected with the positive terminal [49a] of the fourth port [49]; the third filter capacitor [46] is connected in parallel with the third port [48], and the fourth filter capacitor [47] is connected in parallel with the fourth port [49]. The three ports [48] are connected with the battery pack [20], and the fourth port [49] is connected with the DC bus [11]. 4. The hybrid energy storage device for elevators according to claim 1, characterized in that: the hybrid energy storage device is applied to the power supply system of multiple elevators, and each elevator motor [902] communicates with the DC bus [ 11] and share a discharge circuit [100]. 5. A control method for the hybrid energy storage device for elevators according to claim 3, characterized in that: the signal sampling unit [51] in the supercapacitor charge and discharge control circuit [50] samples the grid voltage, the bus voltage, Elevator position, load capacity, speed and acceleration, voltage and charge and discharge current of the supercapacitor bank [10], voltage, temperature, electrolyte density and charge and discharge current of the battery pack [20], the output voltage signal is sent to the A/D converter Unit [52], the A/D conversion unit [52] sends the converted digital signal to the calculation control unit [54]; the user instruction unit [53] sends the user instruction to the calculation control unit [54], and the calculation control unit [54] ] Outputting the control signal according to the set control process, driving the first and second controllable power switch tubes [32, 34] in the supercapacitor charging and discharging circuit [30] through the isolation drive unit [55] to realize the control process; The set control process includes: before the elevator starts to run, control the first controllable power switch tube [32] to cut off, drive the second controllable power switch tube [34], and the DC bus [11] to the supercapacitor bank [10] Power supply; during the start and acceleration process of the elevator, control the second controllable power switch tube [34] to cut off, drive the first controllable power switch tube [32], and the supercapacitor bank [10] provides energy to the DC bus [11] ; During the energy feedback process of the elevator, the first controllable power switch tube [32] is controlled to cut off, the second controllable power switch tube [34] is driven, and the DC bus [11] supplies power to the supercapacitor bank [10]; During the power outage process, control the second controllable power switch tube [34] to cut off, drive the first controllable power switch tube [32], and the supercapacitor bank [10] provides energy to the DC bus [11]; The signal sampling unit [61] of the battery charging and discharging control circuit [60] samples the grid voltage, bus voltage, elevator position, load capacity, speed and acceleration, the voltage and charging and discharging current of the supercapacitor bank [10], and the battery bank [20] The voltage, temperature, electrolyte density and charge and discharge current, the output voltage signal is sent to the A/D conversion unit [62], and the A/D conversion unit [62] sends the converted digital signal to the calculation control unit [64]; the user The instruction unit [63] sends user instructions to the calculation control unit [64], and the calculation control unit [64] outputs control signals according to the set control process, and drives the charging and discharging circuit [40] of the storage battery through the isolation drive unit [65]. The third controllable power switch tube [42] and the fourth controllable power switch tube [44] realize the control process; the set control process includes: before the elevator starts to run, control the third controllable power switch tube [42] ] cut off, drive the fourth controllable power switch tube [44], and the DC busbar [11] supplies power to the storage battery pack [20]; When setting the value, control the fourth controllable power switch tube [44] to cut off, drive the third controllable power switch tube [42], and the battery pack [20] provides energy to the DC bus [11]; Among them, if the terminal voltage of the supercapacitor bank [10] rises to a certain set value, the third controllable power switch tube [42] is controlled to be cut off, and the fourth controllable power switch tube [44] is driven, and the DC bus [11 ] to supply power to the battery pack [20]; during a power outage, control the fourth controllable power switch tube [44] to cut off, drive the third controllable power switch tube [42], and the battery pack [20] to the DC bus [11] ] to provide energy, and its output power is equal to the average power of the elevator during work. 6. A control method for a hybrid energy storage device for an elevator as claimed in claim 5, characterized in that: the supercapacitor charging and discharging control circuit [50] controls the supercapacitor charging and discharging circuit [30], and before the elevator starts to work, The DC busbar [11] charges the supercapacitor bank [10] through the supercapacitor charging and discharging circuit [30]; at the same time, the DC busbar [11] charges the battery pack [20] through the battery charging and discharging circuit [40] in a constant current or pulse manner. ] charge until the state of charge of the supercapacitor bank [10] and battery pack [20] reaches the set value. 7. A control method for a hybrid energy storage device for elevators as claimed in claim 5, characterized in that: the battery charge and discharge control circuit [60] controls the battery charge and discharge circuit [40], and determines the battery charge and discharge circuit [40] according to the system state and user instructions. The working process of the battery pack [20]; when the battery pack [20] needs to provide energy, control the battery charging and discharging circuit [40], so that the battery pack [20] is discharged in a constant current mode; when the battery pack [20] needs to absorb energy , control the battery charging and discharging circuit [40], so that the battery pack [20] is charged in a constant current mode or in a pulse mode.

Images