Elevator hybrid power supply system and elevator hybrid power supply method

Abstract

The application discloses an elevator hybrid power supply system and an elevator hybrid power supply method. The elevator hybrid power supply system comprises an energy storage unit and a monitoring unit, a power grid interaction module, an input end of which is connected with a power grid and is used for bidirectional power conversion, a DC bus group, which comprises a first DC bus used for supplying power to an elevator drive system and a second DC bus used for supplying power to an elevator control system, an output end of the energy storage unit and an output end of the power grid interaction module are connected to the DC bus group, the monitoring unit is connected with the energy storage unit and the power grid interaction module respectively and realizes communication connection, and the monitoring unit is used for controlling a working mode of the power grid interaction module according to total load power on the DC bus group and a state of charge of the energy storage unit.

Description

Technical Field

[0001] This invention relates to the field of elevator technology, and in particular to an elevator hybrid power supply system and elevator hybrid power supply method. Background Technology

[0002] With increasingly stringent building energy efficiency requirements and growing demands for elevator operational reliability, the limitations of traditional elevator power supply systems are becoming increasingly apparent. Currently, elevators primarily rely on a single mains power supply, and energy-saving and backup power supply technologies are generally independent and functionally separated, resulting in low overall system efficiency, poor integration, and insufficient adaptability.

[0003] In terms of elevator energy conservation, the main methods currently used are energy feedback devices and resistor braking. Energy feedback devices can feed the regenerative braking energy generated during elevator operation back to the power grid, achieving a certain degree of energy saving. However, this solution has significant limitations in practical applications: firstly, the feedback energy is constrained by grid connection policies, grid quality, and equipment costs, and its applicability is poor, especially in situations with limited grid capacity or strict power quality requirements; secondly, this device usually only has energy-saving functions and cannot be used as a backup power source in case of grid failure, making its function limited. Resistive braking is more common, as it converts regenerative energy into heat energy by consuming braking resistors, resulting in significant energy waste and contradicting the trend of green building development. Regarding elevator backup power, the traditional approach is to configure an independent uninterruptible power supply (UPS) or emergency generator set. UPS systems typically have limited capacity and are designed only to maintain the elevator control system, lighting, and alarm devices for a short period after a power outage (usually a few minutes), which cannot support the elevator drive system to complete its current operation and safely stop at the nearest floor, posing a safety hazard. While emergency generator sets can provide power for a relatively long time, they suffer from problems such as response delay, high noise, high maintenance costs, and large footprint, and are not suitable for all building applications.

[0004] In recent years, some solutions have attempted to introduce battery energy storage systems for elevator energy saving or backup power, but these solutions often have the following shortcomings: First, the energy-saving system and the backup power system are still separate in terms of hardware architecture and control logic, resulting in redundant equipment configuration, wasted installation space, and a lack of coordination in energy management; second, the system architecture is rigid, making it difficult to adapt flexibly and economically to different application scenarios (such as the construction of new high-rise elevator groups and the renovation of existing single elevators), and the renovation often requires significant changes to the original drive system, resulting in high implementation costs; finally, in terms of battery management, most solutions only have basic monitoring functions and lack active balancing management of the voltage and temperature inconsistencies of the individual cells in the battery pack, which seriously affects the safety, usable capacity, and cycle life of the energy storage system.

[0005] In summary, the separation of the energy-saving subsystem and the backup power subsystem in existing elevator power supply technologies, in terms of function, hardware, and management, is the root cause of the overall low energy efficiency, limited reliability, poor flexibility, and unsatisfactory life-cycle economics of the system. Therefore, there is an urgent need for a highly integrated, intelligent, and flexibly configurable hybrid power supply system to uniformly address the energy-saving, backup power, and adaptability requirements of elevators. Summary of the Invention

[0006] This invention provides a hybrid power supply system for elevators, comprising:

[0007] The power supply energy-saving module includes: an energy storage unit and a monitoring unit;

[0008] The power grid interaction module connects to the power grid at its input end and is used for bidirectional power conversion.

[0009] The DC bus group includes a first DC bus for supplying power to the elevator drive system and a second DC bus for supplying power to the elevator control system;

[0010] The output terminals of the energy storage unit and the grid interaction module are connected to the DC bus group.

[0011] The monitoring unit is connected to the energy storage unit and the power grid interaction module respectively to achieve communication connection;

[0012] The monitoring unit is used to control the operating mode of the grid interaction module based on the total load power on the DC bus group and the state of charge of the energy storage unit.

[0013] Optionally, the power grid interaction module includes a bidirectional AC / DC converter; the first end of the bidirectional AC / DC converter is connected to the power grid, the second end is connected to the DC bus group, and the controlled end is connected to the monitoring unit.

[0014] The elevator hybrid power supply system also includes: a first inverter circuit and an AC bus;

[0015] The input terminal of the first inverter circuit is connected to the output terminal of the energy storage unit and the second terminal of the bidirectional AC / DC converter, and the output terminal is connected to the AC bus.

[0016] The AC bus is used to supply power to the elevator's AC load system.

[0017] Optionally, the elevator hybrid power supply system further includes: a first bidirectional DC-DC converter circuit;

[0018] The first end of the first bidirectional DC-DC converter circuit is connected to the output end of the energy storage unit, the second end is connected to the first DC bus, and the third end is connected to the second DC bus.

[0019] The first bidirectional DC-DC converter circuit is used to convert the voltage at the first terminal and output a first voltage to the first DC bus, and output a second voltage to the second DC bus; or, the first bidirectional DC-DC converter circuit is used to convert the voltage at the second terminal and output it from the first terminal to the output terminal of the energy storage unit.

[0020] The amplitudes of the first voltage and the second voltage are different.

[0021] Optionally, the energy storage unit has three positive energy storage output terminals, and the bidirectional AC / DC converter has three positive converter output terminals;

[0022] The first energy storage positive output terminal and the first converter positive output terminal are connected to the power supply terminal of the elevator drive system.

[0023] The second energy storage positive output terminal and the second converter positive output terminal are connected to the power supply terminal of the elevator control system;

[0024] The third energy storage positive output terminal and the third converter positive output terminal are connected to the input terminal of the first inverter circuit;

[0025] The power supply energy-saving module also includes a balancing unit;

[0026] The balancing unit is used to balance the voltage of each cell connected in series in the cell group when the maximum voltage difference between the cells in the energy storage unit is greater than a preset threshold.

[0027] Optionally, the power grid interaction module includes: a rectifier circuit and an AC converter circuit;

[0028] The input terminal of the rectifier circuit is connected to the power grid, and the output terminal is connected to the power supply terminal of the elevator drive system and the output terminal of the energy storage unit.

[0029] The input terminal of the AC conversion circuit is connected to the power grid, and the output terminal is connected to the power supply terminal of the elevator AC load system; the AC conversion circuit is used to convert the power grid voltage and output it.

[0030] Optionally, the energy storage unit has a first positive energy storage output terminal and a second positive energy storage output terminal;

[0031] The first positive output terminal of the energy storage system is connected to the power supply terminal of the elevator drive system via the first DC bus, and the second positive output terminal of the energy storage system is connected to the power supply terminal of the elevator control system via the second DC bus.

[0032] The number of cells connected in series between the first positive output terminal and the second positive output terminal of the energy storage unit and the negative output terminal of the energy storage unit are different.

[0033] Optionally, the elevator hybrid power supply system further includes: a second inverter circuit;

[0034] The input terminal of the second inverter circuit is connected to the first DC bus and the first energy storage positive output terminal, and the output terminal is connected to the power grid.

[0035] Optionally, the power grid interaction module further includes: a second bidirectional DC-DC conversion circuit;

[0036] The first end of the second bidirectional DC-DC converter circuit is connected to the output end of the energy storage unit, the second end is connected to the first DC bus, and the third end is connected to the second DC bus.

[0037] The second bidirectional DC-DC converter circuit is used to convert the voltage at the first terminal and output a first voltage to the first DC bus, and output a second voltage to the second DC bus; or, the second bidirectional DC-DC converter circuit is used to convert the voltage at the second terminal and output it from the first terminal to the output terminal of the energy storage unit.

[0038] The amplitudes of the first voltage and the second voltage are different.

[0039] Optionally, the power grid interaction module further includes a third inverter circuit;

[0040] The input terminal of the second inverter circuit is connected to the first terminal of the second bidirectional DC-DC converter circuit and the output terminal of the energy storage unit, and the output terminal is connected to the power grid.

[0041] This invention also proposes a hybrid power supply method for elevators, comprising:

[0042] Detect the voltage and current on the first DC bus and the second DC bus, and calculate the total load power;

[0043] Based on the total load power and the state of charge of the energy storage unit, corresponding control commands are output to the grid interaction module; wherein, when the total load power indicates that the elevator is in a regenerative braking state, the grid interaction module is controlled to stop absorbing power from the grid in order to guide regenerative energy to charge the energy storage unit.

[0044] Optionally, the step of outputting corresponding control commands to the grid interaction module based on the total load power and the state of charge of the energy storage unit includes:

[0045] If the total load power indicates that the elevator is in a regenerative braking state, then compare the state of charge with a first preset threshold.

[0046] If the state of charge is greater than a first preset threshold, the grid interaction module is controlled to invert the voltage on the first DC bus and output it to the grid.

[0047] Optionally, the step of outputting corresponding control commands to the grid interaction module based on the total load power and the state of charge of the energy storage unit includes:

[0048] If the total load power indicates that the elevator is in operation, then compare the state of charge with the second preset threshold.

[0049] If the energy storage unit is damaged or the state of charge is less than the second preset threshold, the grid interaction module is controlled to convert the grid voltage into DC voltage and output it to the first DC bus. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0051] Figure 1 This is a first structural schematic diagram of the elevator hybrid power supply system of the present invention;

[0052] Figure 2 This is a schematic diagram of the second structure of the elevator hybrid power supply system of the present invention;

[0053] Figure 3 This is a schematic diagram of the third structure of the elevator hybrid power supply system of the present invention;

[0054] Figure 4 This is a schematic diagram of the fourth structure of the elevator hybrid power supply system of the present invention;

[0055] Figure 5 This is a fifth structural schematic diagram of the elevator hybrid power supply system of the present invention;

[0056] Figure 6 This is a sixth structural schematic diagram of the elevator hybrid power supply system of the present invention;

[0057] Figure 7 This is a schematic diagram of the seventh structure of the elevator hybrid power supply system of the present invention;

[0058] Figure 8 This is the eighth structural schematic diagram of the elevator hybrid power supply system of the present invention.

[0059] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0060] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0061] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0062] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0063] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0064] like Figure 1 As shown, the present invention proposes a hybrid power supply system for elevators, comprising:

[0065] The power supply energy-saving module includes: an energy storage unit and a monitoring unit;

[0066] The power grid interaction module connects to the power grid at its input end and is used for bidirectional power conversion.

[0067] The DC bus group includes a first DC bus for supplying power to the elevator drive system and a second DC bus for supplying power to the elevator control system;

[0068] The output terminals of the energy storage unit and the grid interaction module are connected to the DC bus group.

[0069] The monitoring unit is connected to the energy storage unit and the power grid interaction module via communication connections.

[0070] The monitoring unit is used to control the operating mode of the grid interaction module based on the total load power on the DC bus group and the state of charge of the energy storage unit.

[0071] It should be explained that the elevator hybrid power supply system in this embodiment consists of three main components in its core architecture: a power supply energy-saving module, a power grid interaction module, and a DC bus group. These three components are connected by specific electrical and communication links to form an organic whole.

[0072] The energy storage unit typically uses a battery pack composed of multiple rechargeable batteries (cells, such as lithium iron phosphate batteries) connected in series or parallel. Its core function is to store electrical energy and release it when needed. The energy storage unit has positive and negative output terminals; it is easy to understand that the DC bus may also include a negative bus for connecting the negative output terminals of the energy storage unit, as well as connecting to the elevator drive system, elevator control system, and elevator AC load system. The energy storage unit can have multiple positive output terminals. The monitoring unit is an intelligent controller integrating data acquisition, calculation, decision-making, and communication functions. It establishes bidirectional communication connections with the energy storage unit and the power grid interaction module through sensor lines and a communication bus. The monitoring unit continuously obtains the state of charge (SOC) parameter from the energy storage unit, reflecting the remaining battery capacity.

[0073] The grid interaction module is the sole interface for energy exchange between the system and the external power grid. Its input is connected to a three-phase or single-phase AC power grid. In this invention, this module is defined as capable of bidirectional power conversion, meaning it has two basic operating modes: one is converting AC power from the grid into DC power for transmission to the system (rectification mode); the other is converting DC power from the system back into AC power for transmission to the grid (inverter mode). Specifically, it can be a bidirectional AC / DC converter integrating rectification and inversion functions, or a combination of a rectifier circuit and an independent inverter circuit. The module's output is on the DC side, and its operating mode (rectification or inversion, and specific power commands) is determined by control commands issued by the monitoring unit.

[0074] A DC bus group shall include at least two DC buses with different voltage levels:

[0075] The first DC bus is typically a high-voltage DC bus (e.g., several hundred volts of DC matched to the DC side voltage of the elevator motor drive), specifically used to power the elevator's drive system (mainly the frequency converter and its driven traction motor). The second DC bus is typically a low-voltage DC bus (e.g., 24VDC or 12VDC), specifically used to provide a stable power supply to the elevator's control system (including the main control board, safety circuit, door operator controller, buttons, displays, and other low-voltage loads). Physically, the output terminals (positive and negative) of the energy storage unit and the DC output terminal of the grid interaction module are connected in parallel to the DC bus group. This means that the electrical energy on the first and second DC buses can originate from the output of the grid interaction module and the output of the energy storage unit. The power input terminals of the elevator's drive system and control system are respectively drawn from their corresponding DC buses.

[0076] The operation of the monitoring unit is based on the real-time perception and judgment of two core state variables: the total load power on the DC bus group and the state of charge of the energy storage unit.

[0077] The monitoring unit collects voltage and current signals on the first and second DC buses in real time using high-precision sensors. By instantaneously calculating these signals, the total instantaneous power flowing from the DC bus group to all elevator loads (including drive and control systems) can be obtained. This power value is a signed quantity (vector). In this embodiment, a positive power value indicates that electrical energy flows from the DC bus group to the elevator loads, and the elevators are in a "motor" state consuming electrical energy (e.g., heavy load going up, light load going down); a negative power value indicates that electrical energy flows from the elevator loads (mainly motors in regenerative braking mode) to the DC bus group, and the elevators are in a "power generation" state generating electrical energy (e.g., light load going up, heavy load going down). Therefore, the sign and magnitude of the total load power directly and in real time reflect the overall net power consumption status of the elevator group. Based on the real-time monitored total load power (P) and the state of charge (SOC) read from the energy storage unit management system (BMS), the monitoring unit dynamically adjusts the operating mode of the grid interaction module according to the built-in strategy algorithm, thereby achieving optimal energy scheduling.

[0078] Scenario 1: Regenerative Braking Energy Recovery (Energy Saving). When the monitoring unit calculates that the total load power P < 0, indicating that the elevator is in regenerative braking mode, this signifies excess regenerative energy on the DC bus. At this point, the primary control objective of the monitoring unit is to store and utilize this energy as much as possible, rather than wasting or disposing of it haphazardly. The control command is to reduce or completely stop the power absorbed from the grid by the grid interaction module (i.e., reduce its rectified power or put it into standby mode). This operation alters the system's energy balance. As the power absorbed by the grid decreases while regenerative energy continues to be generated, this excess energy naturally flows to another energy-receiving port in the system—the energy storage unit directly connected in parallel to the bus—to charge it. During this process, the monitoring unit can perform fine-grained management based on the energy storage unit's State of Charge (SOC). For example, this charging operation can be performed only when the SOC is below a certain safe upper limit; if the SOC is full, the grid interaction module can be instructed to switch to inverter mode to feed the regenerative energy back to the grid.

[0079] Scenario 2: Backup Power Switching During Power Grid Anomalies. The monitoring unit continuously monitors the power grid voltage and frequency. When a power grid outage, voltage drop, or frequency anomaly is detected, the monitoring unit immediately identifies it as a "power grid anomaly." At this time, to ensure the safe operation of the elevator, the monitoring unit issues a critical control command: forcing the power grid interaction module to stop working, i.e., disconnecting it from the DC bus or reducing its output to zero. This is equivalent to isolating the power grid from the system. Since the energy storage unit is always connected in parallel to the DC bus, once the power grid interaction module exits, the energy storage unit automatically becomes the sole power source on the DC bus, immediately providing uninterrupted power to the elevator's drive and control systems, supporting the elevator to complete its current journey and safely stop. The monitoring unit manages the discharge process during backup power based on the energy storage unit's State of Charge (SOC) and takes protective measures when the SOC is too low.

[0080] Scenario 3: Conventional Power Supply and Strategic Charging / Discharging. When the power grid is normal and the elevator is in motor mode (P>0), the system defaults to prioritizing power supply to the DC bus group by the grid interaction module in rectification mode. Simultaneously, the monitoring unit can proactively control the grid interaction module to charge the energy storage unit based on time-of-use pricing strategies (such as off-peak hours) and the energy storage unit's state of charge (SOC), achieving peak shaving and valley filling, and reducing operating costs.

[0081] As can be seen from the above, the system described in this invention systematically solves the problems pointed out in the background art through its unique architecture and intelligent control logic:

[0082] 1. Achieving a high degree of integration and synergy between energy saving and backup power functions: The system no longer requires independent energy feedback devices and UPS. Under the unified scheduling of the same energy storage unit and the same grid interaction module, both the "energy saving" task of recovering regenerative braking energy and the "backup power" task of providing emergency power during grid failures are undertaken by the same monitoring unit. Hardware equipment is reused, space occupation and costs are significantly reduced, and energy management changes from isolated to collaborative.

[0083] 2. Significantly improved power supply reliability: Since the energy storage unit and the DC bus group are directly connected in parallel, and the monitoring unit responds to grid anomalies by quickly disconnecting the grid interaction module, the switching process from grid power supply to energy storage power supply can theoretically be seamless, truly achieving "uninterrupted" power supply, supporting the safe stopping of elevators, and solving the pain points of insufficient capacity and inability to support drive systems in traditional UPS systems.

[0084] 3. High flexibility and configurability of the architecture: The architecture proposed in this solution is a general framework. As described in this embodiment, the specific implementation of the power grid interaction module (bidirectional converter or discrete rectifier / inverter), the connection method between the energy storage unit and the bus (whether or not additional DC / DC conversion is required), etc., can be flexibly adjusted and configured according to the voltage level, renovation difficulty, and cost budget of the specific elevator, so as to perfectly adapt to different application scenarios from building new elevator groups to renovating old elevators.

[0085] In the first embodiment, as Figure 2 As shown, the power grid interaction module includes a bidirectional AC / DC converter; the first end of the bidirectional AC / DC converter is connected to the power grid, the second end is connected to the DC bus group, and the controlled end is connected to the monitoring unit.

[0086] The elevator hybrid power supply system also includes: a first inverter circuit and an AC bus;

[0087] The input terminal of the first inverter circuit is connected to the output terminal of the energy storage unit and the second terminal of the bidirectional AC / DC converter, and the output terminal is connected to the AC bus.

[0088] The AC bus is used to supply power to the elevator's AC load system.

[0089] It should be noted that this embodiment provides a preferred and fully functional implementation scheme based on a general architecture. By adopting a specific power grid interaction module and expanding the AC power supply capability, the system's integration and practicality are significantly improved. The core of this embodiment lies in the specification of the "power grid interaction module" and the corresponding expansion of the system's power supply range. Specifically, the power grid interaction module is implemented as a bidirectional AC / DC converter. Simultaneously, the system adds a first inverter circuit and an AC bus, thereby constructing a complete platform capable of providing unified power supply management for all types of elevator loads (DC drive / control system and AC auxiliary load).

[0090] In this embodiment, the grid interaction module is handled by a high-performance bidirectional AC / DC converter. The converter's first terminal (AC terminal) is directly connected to a three-phase or single-phase AC grid via protective devices such as circuit breakers or contactors. Its second terminal (DC terminal) outputs DC power that has undergone power factor correction and voltage regulation, and connects to the system's internal DC bus groups (i.e., the first and second DC buses). The converter integrates sophisticated control circuitry, and its controlled terminal connects to a monitoring unit via a communication bus (such as CAN, RS485, or Ethernet) to receive real-time control commands from the monitoring unit. These commands determine its operating mode (rectification or inversion) and specific output / input power target values. The bidirectional AC / DC converter replaces the traditional unidirectional rectifier, becoming an intelligent and controllable grid interface. Under the command of the monitoring unit, it can function as a "power source," drawing power from the grid to supply power to the entire system or charge energy storage units (rectification mode); or it can function as a "load," feeding excess DC power back to the grid with high quality (inversion mode).

[0091] To power the elevator's AC loads (such as car lighting, fans, alarm devices, and hoistway lighting), this embodiment adds a first inverter circuit and an independent AC bus. The input of the first inverter circuit is connected in parallel with two DC power supplies: one is the output of the energy storage unit, and the other is the DC output of the bidirectional AC / DC converter (i.e., its second terminal). This parallel design means that the DC input power supply of the first inverter circuit has extremely high reliability, allowing it to flexibly draw energy from the energy storage unit or from the grid power rectified by the converter. The output of the first inverter circuit generates stable industrial frequency AC power (such as 220VAC / 50Hz) and connects to the AC bus. All the elevator's AC auxiliary loads draw power from this AC bus.

[0092] In this embodiment, the control logic and energy scheduling strategy of the monitoring unit are richer and more refined:

[0093] When the power grid is normal, the monitoring unit typically instructs the bidirectional AC / DC converter to operate in rectification mode, serving as the main power source to supply power to the DC bus and drive the elevator. Simultaneously, the rectified output also provides energy to the first inverter circuit, which, after inversion, supplies power to the AC bus. When the elevator is in regenerative braking mode (total load power is negative), the converter's rectification power is reduced to prioritize regenerative energy for charging the energy storage unit. If the energy storage unit is full, the monitoring unit can instruct the bidirectional AC / DC converter to switch to inverter mode, directly feeding excess regenerative energy back to the power grid.

[0094] When a power grid anomaly is detected, the monitoring unit executes a critical switching operation: instructing the bidirectional AC / DC converter to immediately stop operating, thereby electrically isolating it from the system. At this time, the entire power supply responsibility of the system is transferred to the energy storage unit. The energy storage unit continues to supply power to the first and second DC buses directly through parallel connection, ensuring uninterrupted operation of the elevator drive and control system. Simultaneously, the output of the energy storage unit also provides DC input to the first inverter circuit, enabling the first inverter circuit to continue operating and supply power to the AC bus and all AC loads on it. This ensures that all loads (DC and AC) of the elevator can receive power support in the event of a power outage, guaranteeing a complete operating environment including lighting and ventilation, and further improving safety and comfort. Because the input power of the first inverter circuit has dual protection (power grid rectification via converter or direct power supply from the energy storage unit), the power supply reliability of the AC loads is also enhanced. The monitoring unit can flexibly select the power source for the AC loads according to the operating strategy. For example, during peak electricity price periods, the energy storage unit can be used to supply power to some AC loads through the first inverter circuit to reduce the burden on the power grid.

[0095] This embodiment employs a bidirectional AC / DC converter, enabling the system to not only draw power from the grid but also feed excess regenerated energy back to the grid with high quality. This is not only more energy-efficient than consuming power through resistors but also potentially generates economic benefits through electricity trading, achieving tiered energy utilization and maximizing system energy efficiency. Furthermore, the newly added first inverter circuit and AC bus integrate the power supply for the elevator's AC loads into a unified intelligent management system. In backup power mode, the AC loads no longer rely on an external UPS or experience a complete power outage; instead, they are uniformly protected by the energy storage system, achieving uninterrupted power supply across the entire chain from drive to control to auxiliary loads, significantly improving the elevator's functional integrity and safety in emergency situations.

[0096] In one example, such as Figure 3 As shown, the elevator hybrid power supply system further includes: a first bidirectional DC-DC converter circuit;

[0097] The first end of the first bidirectional DC-DC converter circuit is connected to the output end of the energy storage unit, the second end is connected to the first DC bus, and the third end is connected to the second DC bus.

[0098] The first bidirectional DC-DC converter circuit is used to convert the voltage at the first terminal and output a first voltage to the first DC bus, and output a second voltage to the second DC bus; or, the first bidirectional DC-DC converter circuit is used to convert the voltage at the second terminal and output it from the first terminal to the output terminal of the energy storage unit.

[0099] The amplitudes of the first voltage and the second voltage are different.

[0100] It should be explained that the first bidirectional DC-DC converter is a functionally defined circuit unit. It is connected between the output of the energy storage unit and the system's DC bus group (the first DC bus and the second DC bus). Once its internal topology is determined, it can autonomously perform the following functions:

[0101] When energy needs to flow from the energy storage unit to the DC bus, this circuit converts the output voltage of the energy storage unit into a first voltage (higher, such as DC 540V) required by the elevator drive system and a second voltage (lower, such as DC 24V) required by the control system, and outputs them to the first and second DC buses respectively. The amplitudes of the first and second voltages are different. When energy needs to flow from the DC bus (mainly from the first DC bus) to the energy storage unit, this circuit receives the electrical energy on the DC bus and converts it into voltage and current suitable for charging the energy storage unit. This circuit is not an active converter controlled by software in real time, but a passive circuit network with a specific topology and parameters. Its core function is determined by the connection relationship and inherent characteristics of its internal components, enabling it to autonomously achieve adaptive energy transfer and voltage conversion between the energy storage unit and DC buses of different voltage levels within the system. The first bidirectional DC-DC conversion circuit is a passive energy routing and voltage conversion network. Its function is to convert the voltage connected to its first end (energy storage end) into two different and stable DC voltages (first voltage and second voltage) and provide them to the second end (connected to the first DC bus) and the third end (connected to the second DC bus) respectively, or allow energy to flow from the DC bus side to the energy storage unit in the opposite direction.

[0102] This example defines a functional circuit module, not a specific integrated circuit model. Its physical implementation can be flexible and varied, as long as the circuit structure can achieve the described "voltage conversion and bidirectional power transfer" function.

[0103] An engineering implementation example of the first bidirectional DC-DC converter circuit is that the circuit can be composed of a bidirectional DC / DC power module with a fixed conversion ratio (connected between the energy storage unit and the first DC bus) and a unidirectional DC / DC buck module with a fixed output (connected between the energy storage unit and the second DC bus). Both modules are themselves standardized passive power components with defined input-output characteristics. The bidirectional DC / DC converter module, connected between the energy storage unit output and the first DC bus, is responsible for handling the bidirectional flow of high-power energy at the drive bus level. The unidirectional DC / DC buck module, connected between the energy storage unit output and the second DC bus, is responsible for providing a stable and accurate low-voltage power supply to the control system.

[0104] Those skilled in the art will understand that passive circuit structures capable of achieving the same function are not limited to the examples described above. For instance, a combination of a power frequency transformer with multiple secondary windings and a rectifier-filter circuit, along with appropriate relays for path switching; or a specific combination of resistor networks and diodes to construct voltage divider and unidirectional conduction paths, etc. The common goal of all these designs is to construct a hardware channel that can achieve specific voltage adaptation and bidirectional energy transmission without the intervention of a core controller.

[0105] The existence of this circuit eliminates the limitation on the fixed voltage requirements of elevator drive and control systems for selecting the voltage of energy storage units (such as battery packs). The system can easily adapt to energy storage units and elevator loads of various voltage levels by configuring this circuit with different specifications or parameters, greatly enhancing the system's versatility and adaptability to diverse application scenarios. The monitoring unit does not need to perform complex real-time control of the voltage transformation process within this circuit; it only needs to decide the macroscopic flow of energy (charging or discharging) at the system level. This reduces the requirements for the monitoring unit's control algorithm, making the system design more modular and clear.

[0106] In another example, such as Figure 2 As shown, the energy storage unit has three positive energy storage output terminals, and the bidirectional AC / DC converter has three positive converter output terminals.

[0107] The first energy storage positive output terminal and the first converter positive output terminal are connected to the power supply terminal of the elevator drive system.

[0108] The second energy storage positive output terminal and the second converter positive output terminal are connected to the power supply terminal of the elevator control system;

[0109] The third energy storage positive output terminal and the third converter positive output terminal are connected to the input terminal of the first inverter circuit;

[0110] The power supply energy-saving module also includes a balancing unit;

[0111] The balancing unit is used to balance the voltage of each cell connected in series in the cell group when the maximum voltage difference between the cells in the energy storage unit is greater than a preset threshold.

[0112] It should be noted that this example provides a more integrated hardware implementation scheme on a general architecture. This scheme is characterized by the fact that both the energy storage unit and the bidirectional AC / DC converter employ a multi-output independent design and are directly connected to different load buses.

[0113] The energy storage unit consists of multiple battery cells (such as lithium iron phosphate cells) connected in series. Its innovation lies in the fact that it doesn't simply draw power from the total positive and negative terminals of the battery pack; instead, it directly extracts three different voltage levels of DC output through internal electrical connections. The first positive output terminal connects to a specific number of cells in the battery pack, and its total voltage is designed to precisely match the high-voltage DC bus voltage (e.g., DC 540V) required by the elevator drive system. The voltage value depends directly on the number of cells connected in series and the voltage of each cell. The second positive output terminal connects to another group of fewer cells in the battery pack, and its total voltage is designed to precisely match the low-voltage DC bus voltage (e.g., DC 24V) required by the elevator control system. The third positive output terminal can be connected to another group of cells, and its voltage is typically designed to supply the subsequent AC inverter circuit.

[0114] To coordinate with this, the DC side of the bidirectional AC / DC converter is also designed with three independent positive output terminals, whose voltage levels correspond precisely to the voltages of the three energy storage positive output terminals. The first energy storage positive output terminal and the first converter positive output terminal are connected to the power supply terminal of the elevator drive system (i.e., the first DC bus). This means that the drive system simultaneously receives power from the energy storage and the power grid (via the converter). The second energy storage positive output terminal and the second converter positive output terminal are connected to the power supply terminal of the elevator control system (i.e., the second DC bus). This is crucial for ensuring absolutely uninterrupted power supply to the control system. As long as either of them has power, the control system receives power, and there is no time interruption during power grid failures. The third energy storage positive output terminal and the third converter positive output terminal are connected to the input terminal of the first inverter circuit, serving as a DC source for generating AC power.

[0115] Since the voltage at each positive output terminal of the energy storage unit is directly drawn from cells connected in series, the consistency of the voltage of each cell within the battery pack directly determines the accuracy and stability of each output voltage. To ensure the reliable operation of this architecture, the power supply and energy-saving module must integrate a high-performance equalization unit. If there is a voltage difference (inconsistency) between cells, it will cause the actual output voltage to deviate from the design value, affecting the normal operation of the load. During discharge, the cell with the lowest voltage will limit the depth of discharge of the entire string of cells; during charging, the cell with the highest voltage will limit the upper limit of charging, resulting in a significant decrease in the overall usable capacity of the energy storage unit and severely weakening its backup power capability.

[0116] The balancing unit continuously monitors the voltage of each cell within the energy storage unit. When the calculated maximum voltage difference (ΔV) between cells exceeds a preset start-up threshold (Vthh), the balancing unit uses its active balancing circuit (such as a capacitor- or inductor-based energy transfer circuit) to transfer energy from the cell with the highest voltage to the cell with the lowest voltage, or to the battery pack bus. The balancing process stops when the maximum voltage difference decreases to below a preset stop threshold (Vthl). Balancing is typically performed actively at the end of charging (constant voltage stage) and when the system is idle to ensure that all cells reach full charge synchronously and to correct inconsistencies during routine maintenance.

[0117] The balancing unit is not an add-on feature, but rather a key element ensuring the practicality and high performance of the architecture in this embodiment. It ensures: Voltage accuracy: Each output voltage remains stable at its design value. Capacity retention: Maximizing the available energy storage capacity of the battery pack and guaranteeing backup power duration. This example represents an optimized path for efficient power supply and backup through the internal architecture design of the battery pack and direct coupling with external circuitry. This example eliminates the need for an external DC / DC converter to provide voltage transformation for the drive and control buses. Energy is delivered directly to the load from the source (specific cell strings for energy storage or grid converter), reducing power conversion stages, lowering energy loss, complexity, and potential failure points, and improving overall energy efficiency and reliability.

[0118] In the second embodiment, as Figure 4 As shown, the power grid interaction module includes: a rectifier circuit and an AC converter circuit;

[0119] The input terminal of the rectifier circuit is connected to the power grid, and the output terminal is connected to the power supply terminal of the elevator drive system and the output terminal of the energy storage unit.

[0120] The input terminal of the AC conversion circuit is connected to the power grid, and the output terminal is connected to the power supply terminal of the elevator AC load system; the AC conversion circuit is used to convert the power grid voltage and output it.

[0121] It should be explained that this embodiment demonstrates another basic and practical implementation of the grid interaction module under the core concept of the invention. Unlike the solution using a bidirectional AC / DC converter, this embodiment uses a circuit combination with discrete functions to achieve grid connection and basic energy management at a more economical cost, and is especially suitable for cost-sensitive applications or applications that do not require energy feedback to the grid.

[0122] In this embodiment, the power grid interaction module consists of two functionally independent circuit units: a rectifier circuit and an AC converter circuit. The rectifier circuit is a unidirectional AC / DC converter whose input is connected to the power grid. Its function is simple and clear: to convert the AC power from the power grid into stable DC power. Its output is directly connected to the power supply terminal of the elevator drive system (i.e., the first DC bus). Simultaneously, this output is also directly connected to the output terminal of the energy storage unit. This means that when the power grid is normal, the rectifier circuit acts as the main power supply for the first DC bus and can also charge the parallel-connected energy storage unit.

[0123] An AC converter circuit performs necessary transformations on the mains voltage (such as step-down, isolation, or regulation) before outputting a safe and compliant AC power supply to the elevator's AC load system (such as lighting, fans, shaft sockets, etc.). Its output is connected to the power supply terminal of the elevator's AC load system. In one example, the AC converter circuit could be an isolation transformer, an AC / AC voltage regulator circuit, or a small-capacity AC / DC + DC / AC secondary converter combination. Its input is also connected to the mains power grid.

[0124] In this architecture, the system's energy path is clear and direct: the first DC bus is directly supported by the outputs of the rectifier circuit and the energy storage unit. The second DC bus (used for the control system) is typically obtained directly from the energy storage unit through its internal design or from a simple DC / DC module (e.g., from different taps of the energy storage unit). AC loads are powered directly from the grid by a separate AC converter circuit, an electrical separation from the DC bus system.

[0125] When the power grid is normal, the rectifier circuit operates, converting AC power to DC power to supply the first DC bus and drive the elevator. The AC converter circuit operates, supplying power to all AC loads. The monitoring unit can control the connection of the energy storage unit's charging circuit according to a strategy (such as off-peak electricity periods), using the DC power output from the rectifier circuit to charge the energy storage unit.

[0126] When the elevator is in regenerative braking mode, the generated electrical energy raises the voltage of the first DC bus. Since the rectifier circuit is unidirectional, the energy cannot be fed back to the grid. At this time, the monitoring unit detects the increase in bus voltage and controls the energy storage unit to connect to the circuit, directly absorbing and storing the regenerated DC energy. If the energy storage unit is full, the system may activate a small energy-consuming resistor to dissipate excess energy to prevent the bus voltage from becoming too high.

[0127] When a power grid anomaly (power outage) is detected, the energy storage unit becomes the sole power source, supplying power to the first DC bus (drive system); simultaneously, it supplies power to the second DC bus (control system) through its second output (or via an internal DC / DC converter). The elevator enters a standby operating state powered solely by the energy storage system. In this mode, AC loads will cease operation due to power loss in the AC conversion circuit, or some critical AC loads can be maintained by a small inverter powered by the energy storage unit (optional expansion).

[0128] This embodiment employs a discrete design for the rectifier circuit and AC converter circuit. Compared to the more expensive bidirectional programmable converter, the cost of the unidirectional rectifier circuit and standard AC converter circuit is significantly lower. This allows the basic functions of the invention (energy storage, energy saving, and backup power) to be achieved at a more economical cost, which is beneficial for promotion in budget-constrained old elevator renovations or low-to-mid-range projects. Although the system cannot feed energy back to the grid to achieve added value, it can still efficiently recover the braking energy regenerated by the elevator and store it in the battery for its own subsequent use, achieving the core energy-saving objective. At the same time, it also has the ability to switch to energy storage power supply in the event of a grid failure, ensuring the safe stopping of the elevator and solving the fundamental problem of backup power reliability.

[0129] It is particularly important to emphasize that the first and second embodiments represent two main technical approaches to grid interaction (bidirectional interactive type and economically based type). This demonstrates that the core architecture of this invention is compatible with and adaptable to grid interface solutions of different performance and cost. Users can flexibly choose appropriate configurations based on the specific investment budget, functional requirements (whether feedback to the grid is required), and policy environment of the project, fully showcasing the flexibility and wide applicability of the system design.

[0130] In one example, such as Figure 5 As shown, the energy storage unit has a first positive energy storage output terminal and a second positive energy storage output terminal;

[0131] The first positive output terminal of the energy storage system is connected to the power supply terminal of the elevator drive system via the first DC bus, and the second positive output terminal of the energy storage system is connected to the power supply terminal of the elevator control system via the second DC bus.

[0132] The number of cells connected in series between the first positive output terminal and the second positive output terminal of the energy storage unit and the negative output terminal of the energy storage unit are different.

[0133] It should be explained that this example specifies the internal structure and output voltage acquisition method of the energy storage unit, demonstrating an efficient solution for directly generating multiple voltages through the internal configuration of the battery pack. The energy storage unit is composed of a large number of individual battery cells connected in series, but its external electrical interface is not a simple positive and negative terminal, but rather a specially designed interface:

[0134] First positive output terminal: This terminal is connected to the positive terminal of a specific number of series-connected cells within the energy storage unit. The number of cells in this group (denoted as M1) is precisely calculated so that the total nominal voltage of these M1 cells connected in series matches the first DC bus voltage (e.g., DC 540V) required by the elevator drive system. For example, if lithium iron phosphate cells with a nominal voltage of 3.2V are used, and a 540V output is required, then M1 is approximately 169 cells (540V / 3.2V≈169). After these 169 cells are connected in series, their first and last terminals constitute the total output voltage, and the first terminal is defined as the first positive output terminal.

[0135] The second positive output terminal for energy storage: This terminal is connected to the same battery pack, but located at the positive terminal of a smaller number of series-connected cells. The number of cells in this group (denoted as M2) is much smaller than M1. Its design goal is to match the total nominal voltage of these M2 cells connected in series with the second DC bus voltage (e.g., DC 24V) required by the elevator control system. For example, if 3.2V cells are used and a 24V output is required, then M2 consists of 8 cells (24V / 3.2V = 7.5, rounded down to 8). These 8 cells can be a segment taken from the total series connection.

[0136] The first and second positive energy storage terminals are located within the energy storage unit, and the number of cells connected in series with the shared negative energy storage terminal differs (i.e., M1 ≠ M2). The second positive energy storage terminal is not derived from the first positive energy storage terminal through an external DC / DC converter, but is directly drawn from an earlier voltage tap point inside the battery pack.

[0137] This example moves the generation of power supply voltage to the assembly and design stage of the energy storage battery pack. By customizing the battery pack design (determining M1 and M2), the voltage requirements of the terminal are met, reflecting a design philosophy of system optimization from the source. This "configurability" is reflected in the ability to customize the production of energy storage battery packs with corresponding tap points (M1, M2) according to the voltage specifications of different elevators. The voltage of the second DC bus is directly taken from a low-voltage section inside the energy storage unit, with no active switches or power semiconductor devices along this path. As long as the cells in this section have power, the control power supply is present, completely eliminating the risk of control power interruption due to external conversion circuit failure. This is the ultimate practice of the "true backup power" concept. The dedicated DC / DC step-down module for powering the control system is omitted, reducing the system's material costs, power consumption, and heat dissipation, while also simplifying wiring and control logic.

[0138] Furthermore, in another example, such as Figure 6 As shown, the elevator hybrid power supply system also includes: a second inverter circuit;

[0139] The input terminal of the second inverter circuit is connected to the first DC bus and the first energy storage positive output terminal, and the output terminal is connected to the power grid.

[0140] It should be explained that this embodiment adds a crucial energy feedback path—a second inverter circuit—to the architecture described in the previous example (which employs an energy storage unit with a specific internal tap structure and a unidirectional rectifier circuit). This addition enables the economical solution, which could only draw power in one direction, to feed excess electrical energy back to the grid, thereby significantly improving the overall energy efficiency and economy of the system.

[0141] The second inverter circuit is a DC / AC inverter that converts direct current (DC) into alternating current (AC) that is in phase and frequency with the power grid. The input of the second inverter circuit is connected to two key points: the first DC bus and the positive output of the first energy storage unit. These two points are electrically connected in parallel; therefore, the input power to the second inverter circuit is the voltage on the DC bus of the drive system, which is supported by the first output of the rectifier circuit or energy storage unit. The output of the second inverter circuit is connected to the power grid after passing through appropriate filtering and protection circuits.

[0142] When the elevator is in regenerative braking mode, the electrical energy generated by the motor raises the voltage of the first DC bus. At this time, the monitoring unit's priority strategy remains controlling the energy storage unit to absorb this energy. However, when the energy storage unit's state of charge (SOC) reaches a preset high threshold (e.g., 95%), i.e., close to full charge, continued charging may damage the battery. In this situation, the monitoring unit will activate the second inverter circuit. The second inverter circuit operates, converting the excess regenerative DC power on the first DC bus into AC power that meets grid requirements and feeding it back to the grid. This avoids energy waste and may also result in some electricity bill deduction benefits.

[0143] Under specific electricity market policies or pricing mechanisms (such as peak-hour pricing periods), the monitoring unit can implement an active energy management strategy. The monitoring unit controls the energy storage unit to discharge to the first DC bus through its first output terminal, while simultaneously activating the second inverter circuit to convert the stored energy (potentially from previous off-peak charging) into AC power and feed it back to the grid, achieving "peak-valley arbitrage" and further improving the system's economic efficiency. The rectifier circuit (unidirectional) and the second inverter circuit (unidirectional) together constitute a system functionally equivalent to a bidirectional converter, but implemented as two discrete components. The rectifier circuit handles the energy inflow from the grid to the system, while the second inverter circuit handles the energy outflow from the system to the grid. The monitoring unit acts as the overall dispatcher, ensuring they do not operate simultaneously to avoid circulating current. That is, the monitoring unit can connect to the control terminal of the second inverter circuit and the control terminal of the rectifier current.

[0144] For systems initially deployed with only basic functions (rectifier circuit + energy storage), energy feedback capabilities can be easily upgraded later by adding a second inverter circuit module. This modular design embodies the flexibility of the "configurable" concept of this invention, allowing users to invest in construction in stages according to their initial budget and future needs. When the energy storage unit is full, the system no longer needs to activate the braking resistor to consume valuable regenerated energy; instead, it can feed it back to the grid to power other equipment within the building or sell it back to the grid. This significantly improves the overall energy utilization efficiency of the system, elevating energy saving from "self-sufficiency" to "contribution to the community," meeting higher standards of green building.

[0145] In the third embodiment, as Figure 7 As shown, the power grid interaction module further includes: a second bidirectional DC-DC conversion circuit;

[0146] The first end of the second bidirectional DC-DC converter circuit is connected to the output end of the energy storage unit, the second end is connected to the first DC bus, and the third end is connected to the second DC bus.

[0147] The second bidirectional DC-DC converter circuit is used to convert the voltage at the first terminal and output a first voltage to the first DC bus, and output a second voltage to the second DC bus; or, the second bidirectional DC-DC converter circuit is used to convert the voltage at the second terminal and output it from the first terminal to the output terminal of the energy storage unit.

[0148] The amplitudes of the first voltage and the second voltage are different.

[0149] It should be explained that this embodiment, based on the basic architecture (including rectifier circuit and AC converter circuit) described in the second embodiment, has made a key upgrade to the interface between the energy storage unit and the DC bus. By introducing a second bidirectional DC-DC conversion circuit, this embodiment overcomes the limitation in the basic scheme that the output voltage of the energy storage unit must be strictly matched with the bus voltage, greatly improving the voltage adaptability and overall performance of the system.

[0150] The second bidirectional DC-DC converter circuit is a functional module capable of realizing bidirectional energy flow and voltage conversion. Its structure can be similar to or equivalent to the first bidirectional DC-DC converter circuit, and will not be described in detail here.

[0151] Discharge direction (energy storage → bus): The second bidirectional DC-DC converter circuit converts the voltage at the first terminal of the energy storage unit and simultaneously outputs a first voltage to the first DC bus and a second voltage to the second DC bus. The first and second voltages have different amplitudes to precisely match the requirements of the drive and control systems.

[0152] Charging direction (bus → energy storage): After converting and integrating the electrical energy from the first DC bus and / or the second DC bus, a suitable charging voltage and current are output to the energy storage unit.

[0153] In the basic scheme, the energy storage unit needs to directly generate a voltage matching the bus through a specific number of cells connected in series internally. This limits battery selection, and the battery state directly affects the bus voltage quality. In this embodiment, the energy storage unit can be designed with any reasonable and efficient voltage platform (e.g., using a standard modular battery pack, such as 48V, 96V, or 400V). The second bidirectional DC-DC converter circuit is responsible for "translating" the energy storage voltage between the 540V drive bus and the 24V control bus. This gives the system design great flexibility.

[0154] Designers can independently choose the technology (voltage, chemical system) of the energy storage unit and the voltage specifications of the elevator. By simply selecting or designing a second bidirectional DC-DC converter with matching parameters, the two can be seamlessly integrated. This allows the same core system solution to be easily adapted to almost all projects, from low-rise residential buildings to super high-rise buildings, from new elevator installations to various complex old elevator renovations, completely solving the industry pain point of "rigid architecture and poor adaptability."

[0155] The second bidirectional DC-DC converter simultaneously converts the stored energy into two highly stable DC voltages. Regardless of how the voltage at the energy storage unit terminals decreases during discharge, this circuit maintains a constant bus voltage through closed-loop regulation, ensuring stable elevator performance throughout the entire standby cycle. Whether recovering regenerative braking energy from the first DC bus or charging using AC power output from the rectifier circuit, the second bidirectional DC-DC converter can implement programmed charging management (such as constant current-constant voltage charging). Through precise control of the charging process, the optimal charging strategy recommended by the battery manufacturer can be strictly implemented, avoiding overcharging, undercharging, and high-current surges that could damage battery life, thereby maximizing the cycle life and overall lifespan economy of the energy storage system.

[0156] Furthermore, such as Figure 8 As shown, in one example, the power grid interaction module further includes a third inverter circuit;

[0157] The input terminal of the second inverter circuit is connected to the first terminal of the second bidirectional DC-DC converter circuit and the output terminal of the energy storage unit, and the output terminal is connected to the power grid.

[0158] It should be explained that, based on the aforementioned architecture (including rectifier circuit, AC converter circuit, and second bidirectional DC converter circuit), this example further integrates a third inverter circuit into the grid interaction module. The introduction of this circuit allows the system to retain its economical architectural advantages and flexible voltage adaptation capabilities, while additionally gaining the ability to directly and efficiently feed energy storage units or regenerated electricity back to the grid, thus achieving complete bidirectional energy interaction with the grid.

[0159] The third inverter circuit is a DC / AC inverter whose core function is to convert DC power into AC power that is in sync with the grid in terms of frequency, phase, and amplitude. Its input is explicitly connected to two key points: the first terminal of the second bidirectional DC-DC converter and the output terminal of the energy storage unit. This connection means that the DC power supply for the third inverter circuit can be drawn from either the direct output of the energy storage unit or from the stored energy after power regulation by the second bidirectional DC-DC converter. This provides flexibility for energy dispatch. The output terminal of the third inverter circuit is connected to the grid, parallel to the input terminal of the rectifier circuit on the AC side, but conflicts are avoided through coordinated control by the monitoring unit. The control terminal of the third inverter circuit is connected to the monitoring unit.

[0160] Faced with fluctuating electricity prices, intermittent renewable energy sources, and changing grid conditions, this system possesses the most comprehensive response capabilities: it can store electricity, use electricity, and feed electricity back to the grid. The monitoring unit can make optimal decisions based on real-time data (electricity prices, SOC, grid commands, load forecasting), ensuring the system always operates in the most economical and grid-stabilizing mode. The system has evolved from an "energy saver" (recycling for self-use) and a "backup provider" (emergency backup) to a "power producer" and a "grid partner." It not only saves on its own electricity costs but also participates in a broader energy market by supplying electricity to the grid, tapping into the potential returns of energy storage assets and significantly improving the overall return on investment and commercial value of the project.

[0161] This invention also proposes a hybrid power supply method for elevators, comprising:

[0162] Detect the voltage and current on the first DC bus and the second DC bus, and calculate the total load power;

[0163] Based on the total load power and the state of charge of the energy storage unit, corresponding control commands are output to the grid interaction module; wherein, when the total load power indicates that the elevator is in a regenerative braking state, the grid interaction module is controlled to stop absorbing power from the grid in order to guide regenerative energy to charge the energy storage unit.

[0164] It should be explained that this method corresponds to the core control logic executed by the monitoring unit in any of the aforementioned system embodiments, and is the "intelligent" essence of this invention. It defines how the system perceives the elevator's operating status, how it makes decisions and controls the energy flow, thereby achieving an organic unity of energy saving and backup power functions. The core lies in a closed-loop control process based on real-time electrical parameter perception and intelligent decision-making. This method does not directly intervene in the elevator's mechanical operation control, but rather intelligently manages the source and destination of electrical energy by continuously monitoring the key status of the power supply network and dynamically scheduling the working mode of the power grid interaction module. Its fundamental goal is to effectively import regenerated electrical energy into the energy storage unit when the elevator is in generator mode; and to seamlessly switch to energy storage power supply when the power grid is abnormal, ensuring operational safety.

[0165] First, the monitoring unit uses high-precision sensors to collect real-time voltage signals (U1, U2) and current signals (I1, I2) on the first and second DC buses. These buses carry the electrical energy of the elevator drive system and control system, respectively. Based on the collected instantaneous data, the monitoring unit calculates the total load power (ΣP) of the system. The calculation method is typically: ΣP = U1 I1+U2 I2. Here, the sign of power follows an important convention: when electrical energy flows from the DC bus to the elevator load (where the elevator consumes electrical energy), ΣP>0; when electrical energy flows from the elevator load (mainly the regenerative braking motor) to the DC bus, ΣP<0. Therefore, the sign of the total load power directly and in real time reflects the overall net power consumption / generation status of the elevator group.

[0166] The monitoring unit then uses the calculated total load power (ΣP) and the state of charge (SOC) of the energy storage unit obtained from the battery management system (BMS) as the core decision-making basis. The monitoring unit determines whether ΣP is less than zero (ΣP<0). If so, the elevator system is determined to be in a regenerative braking state, meaning there is surplus electrical energy being fed back to the DC bus. This is the primary condition for triggering energy recovery operations. After determining the regenerative braking state, the monitoring unit further considers the SOC of the energy storage unit for refined decision-making. For example, if the SOC is below the safety limit (e.g., 95%), the decision is to "store the regenerative energy"; if the SOC is full, the decision may be to "feed the regenerative energy back to the grid" (for systems with bidirectional feedback capabilities). The preset threshold is determined by the R&D personnel.

[0167] Based on the above decision, the monitoring unit outputs the corresponding control commands to the power grid interaction module.

[0168] Core scenario: Regenerative energy charging. When it is determined that the regenerative braking state is met and the energy storage is rechargeable, the monitoring unit executes key control: instructing the grid interaction module to reduce or completely stop absorbing power from the grid (e.g., reduce its rectified power or put it into standby mode).

[0169] The grid interaction module is the main controlled pathway connecting the power grid and the DC bus. Reducing its power intake from the grid is equivalent to reducing a major "energy consumer" on the DC bus. At this point, the surplus energy generated by the elevator's regenerative braking on the DC bus (manifested as an upward trend in bus voltage) will naturally seek other acceptable "energy receivers." Since the output of the energy storage unit is directly or indirectly connected to the DC bus via a conversion circuit, it becomes the most direct energy receiving target. Therefore, regenerated energy can be "guided" into the energy storage unit for charging. This "guidance" is not achieved through direct control of the energy storage unit, but rather indirectly by adjusting the upstream port of the grid interaction module, thereby altering the system's energy balance.

[0170] It is particularly important to emphasize that the effectiveness of this method rests on the system's hardware architecture: the mathematical judgment of total load power ΣP<0 is physically based on detecting that the direction of DC bus current flow is opposite to the discharge direction defined by the polarity of the bus voltage, i.e., energy is flowing backward. This is a reliable electrical characteristic for determining whether the elevator is generating electricity. Based on the hardware foundation of the energy storage unit being directly connected in parallel with the bus or connected through a low-impedance path, the energy exchange difference between the bus voltage and the grid is adjusted by controlling the grid interaction module—the only controlled unit directly interacting with the grid—thereby forcing or allowing regenerated energy to flow to the energy storage unit. This is a clever and efficient indirect control strategy. The monitoring unit, as the main executor of the method, is an embedded system integrating data acquisition, high-speed computation, logical judgment, and communication control. It runs a pre-set algorithm program, periodically executing the above steps to achieve real-time control.

[0171] This method uses a single perception-decision process to simultaneously serve the dual objectives of "energy recovery" and "energy preparation." The detection and response to regenerative braking directly achieves energy savings; while the management logic for maintaining the State of Charge (SOC) of the energy storage unit reserves energy for backup power functions. These two aspects are seamlessly unified at the algorithm level. Furthermore, the judgment based on instantaneous power calculation (ΣP) is extremely rapid, enabling immediate response to the frequent short-term braking and power generation during elevator operation. The guidance method of "giving way" through the control of the grid interaction module ensures high energy path efficiency and fast response in a directly connected hardware topology, guaranteeing the immediacy and efficiency of energy recovery. This method allows the system to accurately perceive the energy situation and make optimal scheduling decisions solely through its own electrical monitoring, without relying on complex external elevator operating status signals, reducing system integration complexity and improving adaptability.

[0172] In one example, the step of outputting corresponding control commands to the grid interaction module based on the total load power and the state of charge of the energy storage unit includes:

[0173] If the total load power indicates that the elevator is in a regenerative braking state, then compare the state of charge with a first preset threshold.

[0174] If the state of charge is greater than a first preset threshold, the grid interaction module is controlled to invert the voltage on the first DC bus and output it to the grid.

[0175] It should be explained that the specific regulations stipulate that when the system captures regenerative braking energy, but the energy storage unit is already close to full charge, the energy should be fed back to the grid through an inverter, thereby achieving a higher level of energy utilization while ensuring the safety of the energy storage system.

[0176] First, the monitoring unit continuously calculates the total load power ΣP. When ΣP < 0, it is determined that the elevator is in regenerative braking mode, and the DC bus has excess regenerative energy. Subsequently, the monitoring unit immediately reads the real-time state of charge (SOC) of the energy storage unit and compares it with a pre-set and stored first preset threshold. This threshold represents the upper limit of safe charging allowed for the energy storage unit, and is typically set to a high value, such as 92%, 95%, or 98%, depending on the electrochemical characteristics of the battery used, lifespan considerations, and system safety margin. This threshold is the intersection of the battery management system's (BMS) safety strategy and energy management strategy. Setting it below 100% (e.g., 95%) is to reserve a buffer space to prevent individual cells from being overcharged due to measurement delays, control errors, or cell imbalances. It ensures that the energy storage system always operates within a safe range.

[0177] If SOC ≤ the first preset threshold: This indicates that the energy storage unit still has sufficient charging capacity. The monitoring unit will control the grid interaction module to reduce power draw from the grid and guide renewable energy to prioritize charging the energy storage unit.

[0178] If the State of Charge (SOC) exceeds the first preset threshold, this indicates that the energy storage unit's charge is nearing saturation. Forcing charging at this point could lead to overcharging, damaging the battery's lifespan and safety. In this situation, storing energy in the energy storage unit should be abandoned, and the energy should instead be fed into the grid. The monitoring unit sends a command to the grid interaction module, controlling its internal power circuits (such as the second or third inverter circuit) to operate in inverter mode. Once activated, the inverter circuit converts the DC voltage generated by regenerative braking on the first DC bus into high-quality AC power with the same frequency, phase, and amplitude as the grid voltage. The AC power generated by the inverter is then safely injected into the grid through a grid-connected switch.

[0179] By setting safe charging thresholds and implementing feedback strategies, the risk of overcharging the energy storage battery pack is absolutely avoided, which is one of the most important safety protection measures for battery systems. In the long run, this significantly extends the battery's cycle life and reduces the system's total life-cycle maintenance costs. When the energy storage unit is full, the system does not convert valuable regenerated energy into heat dissipation through braking resistors, but instead converts it into valuable commercial energy to feed back into the grid. This elevates the system's overall energy efficiency from "self-circulation" to a higher level of "contribution to the outside world."

[0180] In another example, the step of outputting corresponding control commands to the grid interaction module based on the total load power and the state of charge of the energy storage unit includes:

[0181] If the total load power indicates that the elevator is in operation, then compare the state of charge with the second preset threshold.

[0182] If the energy storage unit is damaged or the state of charge is less than the second preset threshold, the grid interaction module is controlled to convert the grid voltage into DC voltage and output it to the first DC bus.

[0183] It should be explained that this example is designed for special operating conditions where the energy storage system itself is in an abnormal state or lacks sufficient energy. It ensures that when the main energy storage function fails, the system can automatically and reliably revert to the most basic grid power supply mode, thereby maintaining the basic operating capability of the elevator.

[0184] First, the monitoring unit confirms that the elevator is in a power-consuming "operating state". This is usually achieved by determining that the total load power ΣP>0, indicating that electrical energy is flowing from the DC bus to the elevator drive and control system.

[0185] Simultaneously or periodically, the monitoring unit performs in-depth condition diagnostics on the energy storage unit. This includes:

[0186] State of charge (SOC) assessment: Read real-time SOC values.

[0187] State of Health (SOH) and Fault Diagnosis: The internal parameters of the energy storage unit are monitored by the Battery Management System (BMS), such as cell voltage balance, abnormal temperature, communication interruption, and rapid change in internal resistance, in order to comprehensively determine whether the energy storage unit is damaged or has a serious fault (e.g., a battery module is disconnected, BMS alarm, insulation failure, etc.).

[0188] The monitoring unit compares the real-time SOC of the energy storage unit with a preset second threshold. This threshold represents the lower limit of safe discharge allowed by the energy storage unit, typically set at, for example, 20%, 15%, or 10%, to prevent damage from over-discharge. Emergency power supply mode is triggered if any of the following conditions are met:

[0189] Condition A (Hardware Failure): The diagnostic result indicates "energy storage unit damaged". This is an absolute trigger condition, regardless of the SOC.

[0190] Energy storage unit failure does not simply mean the battery has no voltage output at all, but encompasses all critical alarm states reported by the BMS, including but not limited to: short circuit, open circuit, temperature runaway, severe imbalance, and communication loss. Upon receiving these fault signals, the monitoring unit considers the energy storage unit unusable.

[0191] Condition B (Energy Depletion): The state of charge (SOC) of the energy storage unit is less than the second preset threshold. This indicates that the stored energy capacity has fallen below the safety reserve line and is insufficient to support reliable backup power functions.

[0192] The second preset threshold prevents irreversible capacity loss, shortened lifespan, or safety risks caused by over-discharge of the energy storage unit, ensuring that the energy storage unit still has sufficient energy reserves to execute a complete "safe docking" procedure in the event of a grid anomaly. When the SOC falls below this threshold, the system considers the energy storage unreliable and actively switches back to grid power supply.

[0193] Once the above triggering conditions are met, the monitoring unit immediately generates and issues an emergency control command, controlling the power grid interaction module to operate in rectification mode, converting (rectifying and stabilizing) the connected AC voltage of the power grid into a stable DC voltage, and outputting it to the first DC bus.

[0194] This emergency mode typically takes higher priority than the electricity price-based strategic discharge mode. When this mode is triggered, the system will forcibly switch to the grid power supply mode to ensure the continuous operation of the elevator, regardless of the current energy-saving or economical operating mode.

[0195] This example allows the system to automatically switch to a traditional, reliable direct mains power supply mode even in the worst-case scenario where the core energy storage module completely fails, ensuring that the elevator never stops due to a power supply system failure. This greatly improves product availability and customer trust.

[0196] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A hybrid power supply system for elevators, characterized in that, include: The power supply energy-saving module includes: an energy storage unit and a monitoring unit; The DC bus group includes a first DC bus for supplying power to the elevator drive system and a second DC bus for supplying power to the elevator control system; The power grid interaction module includes a bidirectional AC / DC converter; the first end of the bidirectional AC / DC converter is connected to the power grid, the second end is connected to the DC bus group, and the controlled end is connected to the monitoring unit. The output terminals of the energy storage unit and the grid interaction module are connected to the DC bus group. The monitoring unit is connected to the energy storage unit and the power grid interaction module respectively to achieve communication connection; The monitoring unit is used to acquire the total load power on the DC bus group, determine the elevator's operating status based on the total load power, and control the operating mode of the bidirectional AC / DC converter based on the operating status and the state of charge of the energy storage unit.

2. The elevator hybrid power supply system as described in claim 1, characterized in that, The elevator hybrid power supply system also includes: a first inverter circuit and an AC bus; The input terminal of the first inverter circuit is connected to the output terminal of the energy storage unit and the second terminal of the bidirectional AC / DC converter, and the output terminal is connected to the AC bus. The AC bus is used to supply power to the elevator's AC load system.

3. The elevator hybrid power supply system as described in claim 2, characterized in that, The elevator hybrid power supply system also includes: a first bidirectional DC-DC converter circuit; The first end of the first bidirectional DC-DC converter circuit is connected to the output end of the energy storage unit, the second end is connected to the first DC bus, and the third end is connected to the second DC bus. The first bidirectional DC-DC converter circuit is used to convert the voltage at the first terminal and output a first voltage to the first DC bus, and output a second voltage to the second DC bus; or, the first bidirectional DC-DC converter circuit is used to convert the voltage at the second terminal and output it from the first terminal to the output terminal of the energy storage unit. The amplitudes of the first voltage and the second voltage are different.

4. The elevator hybrid power supply system as described in claim 2, characterized in that, The energy storage unit has three positive energy storage output terminals, and the bidirectional AC / DC converter has three positive converter output terminals. The first energy storage positive output terminal and the first converter positive output terminal are connected to the power supply terminal of the elevator drive system. The second energy storage positive output terminal and the second converter positive output terminal are connected to the power supply terminal of the elevator control system; The third energy storage positive output terminal and the third converter positive output terminal are connected to the input terminal of the first inverter circuit; The power supply energy-saving module also includes a balancing unit; The balancing unit is used to balance the voltage of each cell connected in series in the cell group when the maximum voltage difference between the cells in the energy storage unit is greater than a preset threshold.

5. The elevator hybrid power supply system as described in claim 1, characterized in that, The power grid interaction module includes: a rectifier circuit and an AC converter circuit; The input terminal of the rectifier circuit is connected to the power grid, and the output terminal is connected to the power supply terminal of the elevator drive system and the output terminal of the energy storage unit. The input terminal of the AC conversion circuit is connected to the power grid, and the output terminal is connected to the power supply terminal of the elevator AC load system; the AC conversion circuit is used to convert the power grid voltage and output it.

6. The elevator hybrid power supply system as described in claim 5, characterized in that, The energy storage unit has a first positive energy storage output terminal and a second positive energy storage output terminal; The first positive output terminal of the energy storage system is connected to the power supply terminal of the elevator drive system via the first DC bus, and the second positive output terminal of the energy storage system is connected to the power supply terminal of the elevator control system via the second DC bus. The number of cells connected in series between the first positive output terminal and the second positive output terminal of the energy storage unit and the negative output terminal of the energy storage unit are different.

7. The elevator hybrid power supply system as described in claim 6, characterized in that, The elevator hybrid power supply system also includes: a second inverter circuit; The input terminal of the second inverter circuit is connected to the first DC bus and the first energy storage positive output terminal, and the output terminal is connected to the power grid.

8. The elevator hybrid power supply system as described in claim 5, characterized in that, The power grid interaction module further includes: a second bidirectional DC-DC conversion circuit; The first end of the second bidirectional DC-DC converter circuit is connected to the output end of the energy storage unit, the second end is connected to the first DC bus, and the third end is connected to the second DC bus. The second bidirectional DC-DC converter circuit is used to convert the voltage at the first terminal and output a first voltage to the first DC bus, and output a second voltage to the second DC bus; or, the second bidirectional DC-DC converter circuit is used to convert the voltage at the second terminal and output it from the first terminal to the output terminal of the energy storage unit. The amplitudes of the first voltage and the second voltage are different.

9. The elevator hybrid power supply system as described in claim 8, characterized in that, The power grid interaction module also includes a third inverter circuit; The input terminal of the third inverter circuit is connected to the first terminal of the second bidirectional DC-DC converter circuit and the output terminal of the energy storage unit, and the output terminal is connected to the power grid.

10. A hybrid power supply method for elevators, characterized in that, The elevator hybrid power supply method, applied to any one of claims 1 to 9, comprises: Detect the voltage and current on the first DC bus and the second DC bus, and calculate the total load power; Based on the total load power and the state of charge of the energy storage unit, corresponding control commands are output to the grid interaction module; wherein, when the total load power indicates that the elevator is in a regenerative braking state, the grid interaction module is controlled to stop absorbing power from the grid and guide regenerated electrical energy to charge the energy storage unit.

11. The elevator hybrid power supply method as described in claim 10, characterized in that, The step of outputting corresponding control commands to the grid interaction module based on the total load power and the state of charge of the energy storage unit includes: If the total load power indicates that the elevator is in a regenerative braking state, then the state of charge is compared with a first preset threshold; wherein, the first preset threshold is the safe upper limit value for charging of the energy storage unit. If the state of charge is greater than a first preset threshold, the grid interaction module is controlled to invert the voltage on the first DC bus and output it to the grid.

12. The elevator hybrid power supply method as described in claim 10, characterized in that, The step of outputting corresponding control commands to the grid interaction module based on the total load power and the state of charge of the energy storage unit includes: If the total load power indicates that the elevator is in operation, then the state of charge and the second preset threshold are compared; wherein, the second preset threshold is the safe lower limit value for the energy storage unit to discharge. If the energy storage unit is damaged or the state of charge is less than the second preset threshold, the grid interaction module is controlled to convert the grid voltage into DC voltage and output it to the first DC bus.

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