Energy storage voltage stabilizer for high-power multi-motor servo system and control method thereof

Abstract

The application relates to the technical field of energy management, and provides an energy storage voltage stabilizer for a high-power multi-motor servo system and a control method thereof, which comprises a main motor driver, an energy storage motor driver, a braking chopper and braking resistor unit, a controller and a rectifier, a soft start circuit and a common DC bus connected in sequence; a bidirectional voltage-lifting converter is arranged on the common DC bus, the high-voltage side of the bidirectional voltage-lifting converter is connected in parallel with the positive bus end and the negative bus end of the common DC bus, and the low-voltage side of the bidirectional voltage-lifting converter is connected with an energy storage unit; the input ends of the main motor driver and the energy storage motor driver are connected in parallel with the positive bus end and the negative bus end of the common DC bus; the braking chopper and the braking resistor unit are connected across the positive bus end and the negative bus end of the common DC bus; the controller is used for controlling the charging and discharging power of the bidirectional voltage-lifting converter and controlling the conduction of the braking chopper and the braking resistor unit. Energy waste is avoided.

Description

Technical Field

[0001] This invention belongs to the field of energy management technology, and in particular relates to an energy storage voltage regulator and its control method for high-power multi-motor servo systems. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] In a high-power multi-motor servo system with a common DC bus, the main motor generates regenerative energy during braking, which increases the voltage of the common DC bus. Traditional solutions often use braking resistors to consume this regenerative energy, which results in energy waste, high heat generation, and limited braking resistor capacity. Meanwhile, during heavy load acceleration or grid fluctuations, the voltage of the common DC bus may drop, affecting the stable operation of the drive. Summary of the Invention

[0004] To address the technical problems mentioned above, this invention provides an energy storage voltage regulator and its control method for high-power multi-motor servo systems. By introducing a bidirectional buck-boost converter to stabilize the bus voltage, and connecting the low-voltage side of the bidirectional buck-boost converter to an energy storage unit, the regenerative energy generated during energy utilization can be preferentially directed to the energy storage unit for storage, thus avoiding energy waste.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of the present invention provides an energy storage regulator for a high-power multi-motor servo system, comprising a main motor driver, an energy storage motor driver, a braking chopper and braking resistor unit, a controller, and a rectifier, a soft-start circuit and a common DC bus connected in sequence. A bidirectional buck-boost converter is installed on the common DC bus, and the high-voltage side of the bidirectional buck-boost converter is connected in parallel to the positive and negative bus terminals of the common DC bus. The low-voltage side of the bidirectional buck-boost converter is connected to an energy storage unit. The input terminal of the main motor driver is connected in parallel to the positive and negative bus terminals of the common DC bus, and the output terminal of the main motor driver is connected to the main motor. The input terminal of the energy storage motor driver is connected in parallel to the positive and negative bus terminals of the common DC bus, and the output terminal of the energy storage motor driver is connected to the energy storage motor. The two ends of the braking chopper and braking resistor unit are connected across the positive and negative bus terminals of the common DC bus. The controller is used to control the charging and discharging power of the bidirectional buck-boost converter and to control the conduction of the braking chopper and braking resistor unit.

[0006] Furthermore, the controller is configured to control the bidirectional buck-boost converter to enter the feedback absorption mode when the common DC bus voltage is higher than the first threshold and the energy storage unit is not saturated with charge.

[0007] Furthermore, the controller is configured to control the bidirectional buck-boost converter to enter the bus support mode when the common DC bus voltage is lower than the second threshold and the energy storage unit's state of charge is higher than the lower limit.

[0008] Furthermore, the controller is configured to control the bidirectional buck-boost converter to enter standby mode when the difference between the common DC bus voltage and the first threshold is less than a set value and the common DC bus current is 0.

[0009] Furthermore, the first threshold is the average of the minimum charging voltage and the maximum charging voltage of the energy storage unit.

[0010] Furthermore, it is used to control the bidirectional buck-boost converter to enter the current-limiting maintenance mode when the common DC bus current is less than the current threshold, and the current threshold is positively correlated with the maximum charging current of the energy storage unit.

[0011] Furthermore, the controller is used to trigger the braking chopper and braking resistor unit to conduct when the energy storage unit voltage reaches the energy storage unit saturation threshold or a bidirectional buck-boost converter fault is detected, so as to limit the common DC bus voltage from not exceeding the safety threshold.

[0012] Furthermore, the faults of the bidirectional buck-boost converter include: when the output current of the bidirectional buck-boost converter exceeds the maximum current of the energy storage unit, it is judged as an overcurrent fault; when the output voltage of the bidirectional buck-boost converter exceeds the maximum charging voltage of the energy storage unit, it is judged as an overvoltage fault.

[0013] Furthermore, the braking chopper and braking resistor unit includes an energy storage braking converter control system, a voltage comparator, a braking resistor, and a power switching device. The input terminal of the energy storage braking converter control system is connected to the output terminal of the bidirectional buck-boost converter. The voltage comparator is connected to the output terminal of the energy storage braking converter control system and the output terminal of the bidirectional buck-boost converter. The braking resistor is connected to the input terminal of the bidirectional buck-boost converter through the power switching device.

[0014] A second aspect of the present invention provides a control method for an energy storage voltage regulator for a high-power multi-motor servo system, applicable to the energy storage voltage regulator for a high-power multi-motor servo system provided in the first aspect, comprising: Obtain the common DC bus voltage and energy storage unit voltage; Based on the common DC bus voltage and the energy storage unit voltage, the charging and discharging power of the bidirectional buck-boost converter is controlled, and the conduction of the braking chopper and braking resistor unit is also controlled.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention stabilizes the bus voltage by introducing a bidirectional buck-boost converter, and the low-voltage side of the bidirectional buck-boost converter is connected to an energy storage unit. During energy utilization, the generated regenerative energy can be preferentially directed to the energy storage unit for storage, thus avoiding energy waste.

[0016] This invention proposes a dual protection mechanism (energy storage absorption + braking discharge) to enhance safety: when the energy storage unit is not saturated, the bus feedback energy is preferentially transferred to the energy storage unit through bidirectional Buck-Boost to achieve energy recovery and bus voltage stabilization; when the energy storage unit reaches the saturation limit or the energy storage branch is faulty / insufficient absorption capacity, the braking chopper unit is controlled to conduct, and the excess energy is discharged by the braking resistor, thereby suppressing bus overvoltage and ensuring safety.

[0017] The bidirectional buck-boost converter and energy storage unit of the present invention are connected in parallel to a common DC bus, without requiring significant modifications to the existing main driver structure. Energy feedback, voltage regulation and protection functions can be added without changing the existing equipment. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0019] Figure 1 This is a framework diagram of an energy storage voltage regulator for a high-power multi-motor servo system according to Embodiment 1 of the present invention; Figure 2 This is a structural diagram of a high-power multi-motor servo system according to Embodiment 1 of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0021] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0022] Example 1 This embodiment provides an energy storage voltage regulator for high-power multi-motor servo systems.

[0023] To achieve energy recovery and busbar stability, there is an urgent need for a device that can achieve bidirectional energy regulation of the busbar without changing the main drive structure and has redundant overvoltage protection.

[0024] How to construct an energy storage voltage regulator for a high-power multi-motor servo system with a common DC bus, based on actual engineering conditions, and improve energy utilization, has become a technical problem to be solved.

[0025] The energy storage voltage regulator provided in this embodiment for high-power multi-motor servo systems is suitable for high-power multi-motor servo systems with a common DC bus, such as... Figure 2 As shown, the high-power multi-motor servo system with a common DC bus includes a main motor and an energy storage motor. The main motor and the energy storage motor are connected by mechanical coupling. The main motor and the energy storage motor are rigidly connected coaxially through a coupling, and a speed / torque sensor is installed on the coupling.

[0026] The energy storage voltage regulator provided in this embodiment for high-power multi-motor servo systems is directly connected to the main motor via port B and to the signal / control link of the energy storage motor via port A. An incremental encoder is connected to the output shaft of the energy storage motor to accurately measure the speed, position, and direction of the energy storage motor, providing core feedback data for the energy storage voltage regulator.

[0027] The incremental encoder has a resolution of any value within the range of 1000-5000 PPR, and the acquired signal is used for monitoring by the host computer and controller or for closed-loop control.

[0028] The energy storage voltage regulator provided in this embodiment for high-power multi-motor servo systems, such as... Figure 1 As shown, it includes: (1) A sampling unit, comprising: test point 1 located on the AC circuit side and test point 2 located on port B side. Test point 1 is used to collect the common DC bus voltage. Bus current Test point 2 is used to collect the voltage on the energy storage side. Energy storage side current .

[0029] (2) AC input and rectification unit (i.e., rectifier), located between AC circuit and soft start circuit, is used to convert AC power from AC circuit to DC power and output it to common DC bus.

[0030] (3) Soft start pre-charge unit, connected between rectifier and common DC bus, is used to limit power-on inrush current and complete bus pre-charge.

[0031] (4) Common DC bus, with positive bus end and negative bus end.

[0032] The common DC bus starts from the output terminal of the soft-start circuit (i.e., the bus power supply point formed after the DC side is powered on) and extends along... Figure 1 The middle two busbars run through the left and right sides, connecting the main motor driver, energy storage motor driver, the high-voltage side of the bidirectional Buck-Boost converter, and the braking chopper / braking resistor branch together. The positive busbar corresponds to... Figure 1 Point A is marked in the diagram; the negative busbar end corresponds to point B marked in the diagram.

[0033] (5) Energy storage branch, including energy storage unit and bidirectional Buck-Boost converter. The high voltage side of the bidirectional Buck-Boost converter is connected in parallel to the positive and negative bus terminals of the common DC bus, and the low voltage side is connected to the energy storage unit.

[0034] The energy storage unit is either a supercapacitor or a battery.

[0035] Preferably, the energy storage unit is a supercapacitor with a capacitance value in the range of 10-50F, or it is composed of multiple supercapacitors connected in series and parallel, and a voltage equalization / protection circuit is configured at its port.

[0036] (6) Main motor driver. The input terminal of the main motor driver is connected in parallel to the positive bus terminal and the negative bus terminal of the common DC bus. Specifically, the input terminal of the main motor driver is connected to a bidirectional Buck-Boost converter, and the output terminal of the main motor driver is connected to the main motor through port B.

[0037] (7) Energy storage motor driver: The output terminal of the bidirectional Buck-Boost converter is connected to the input terminal of the energy storage motor driver, that is, the input terminal of the energy storage motor driver is connected in parallel to the positive bus terminal and the negative bus terminal of the common DC bus, and the output terminal of the energy storage motor driver is connected to the energy storage motor through port A.

[0038] (8) A braking chopper and braking resistor unit, whose two ends are connected across the positive and negative bus terminals of the common DC bus, is used to release energy when the bus is overvoltage or the energy storage branch cannot absorb energy. Specifically, it includes an energy storage braking converter control system, a voltage comparator, a braking resistor, and a power switching device. The input terminal of the energy storage braking converter control system is connected to the output terminal of the bidirectional Buck-Boost converter. The voltage comparator is connected to the output terminal of the energy storage braking converter control system and the output terminal of the bidirectional Buck-Boost converter. The braking resistor is connected to the input terminal of the bidirectional Buck-Boost converter through the power switching device.

[0039] The braking resistor has a resistance value of any value in the range of 50-300Ω, the power switching device is an IGBT (insulated gate bipolar transistor) or a MOSFET (metal-oxide-semiconductor transistor), and it is equipped with overcurrent / overtemperature protection.

[0040] (9) Controller (PLC), used to control the charging and discharging power of the bidirectional Buck-Boost converter and control the conduction / switching of the braking chopper and braking resistor units according to the sampled signal, thereby realizing the common DC bus voltage regulation and braking protection. It includes a host computer, a main motor controller, an energy storage motor controller and a load controller. The main motor controller, energy storage motor controller and load controller are all connected to the host computer. The main motor controller is also connected to the main motor driver, the energy storage motor controller is also connected to the energy storage motor driver, and the load controller is also connected to the voltage comparator and power switching devices.

[0041] The controller employs a threshold hysteresis strategy: when Above the first threshold And when the SOC is not saturated, the bidirectional Buck-Boost converter is controlled to enter the feedback absorption mode; when Below the second threshold Furthermore, when the SOC is higher than the lower limit, the bidirectional Buck-Boost converter is controlled to enter the bus support mode; and in At this time, the bidirectional Buck-Boost converter is controlled to enter standby or current-limiting maintenance mode. Among these, Greater than .

[0042] Among them, the controller is based on the voltage of the energy storage unit. Reaching the saturation threshold of the energy storage unit Alternatively, if a fault is detected in the bidirectional Buck-Boost converter, the braking chopper and braking resistor unit are triggered to conduct, thereby limiting the common DC bus voltage to not exceed the safety threshold. .

[0043] The energy storage voltage regulator provided in this embodiment for high-power multi-motor servo systems achieves voltage regulation of the common DC bus and improves voltage fluctuations under heavy load acceleration / grid disturbances: In traditional high-power multi-motor servo systems, when the load changes, especially under heavy load acceleration or grid disturbances, the bus voltage is prone to fluctuations, which will have a negative impact on stability. In order to solve this problem, this embodiment introduces a bidirectional Buck-Boost converter to regulate the bus voltage.

[0044] The energy storage regulator provided in this embodiment for high-power multi-motor servo systems enables regenerative energy recovery, significantly reducing braking resistor energy consumption and heat load. In traditional high-power multi-motor servo systems, the energy generated during braking is usually converted into heat energy through the braking resistor, leading to energy loss and increased heat load. However, this embodiment, by introducing a bidirectional Buck-Boost converter and an energy storage unit, can recover the energy generated during braking. During energy utilization, the generated regenerative energy can be preferentially directed to the energy storage unit (supercapacitor) for storage, avoiding energy waste.

[0045] The energy storage voltage regulator provided in this embodiment for high-power multi-motor servo systems adopts a dual protection mechanism (energy storage absorption + braking discharge) to improve safety: when the energy storage unit is not saturated, the feedback energy from the bus is preferentially transferred to the energy storage unit through bidirectional Buck-Boost to achieve energy recovery and bus voltage regulation; when the energy storage unit reaches the saturation limit or the energy storage branch is faulty / insufficient in absorption capacity, the braking chopper unit is controlled to conduct, and the excess energy is discharged by the braking resistor, thereby suppressing bus overvoltage and ensuring safety.

[0046] In other words: when the bus is undervoltage, the energy storage unit supports the bus. When the bus voltage is undervoltage, the energy storage unit can release energy to the bus in a timely manner to maintain the stability of the bus voltage and ensure the normal operation of each component. When the energy storage is saturated or malfunctions, the braking resistor provides safe discharge. When the energy storage unit reaches saturation and can no longer store energy or malfunctions and cannot work normally, the excess energy is safely discharged through the cooperation of the braking chopper circuit and the resistor to prevent damage caused by energy overload.

[0047] The energy storage regulator for high-power multi-motor servo systems provided in this embodiment does not change the main driver structure and is easy to implement in engineering: the bidirectional Buck-Boost converter and the energy storage unit are connected in parallel to a common DC bus, without the need for significant modifications to the existing main driver structure. Energy feedback, voltage regulation and protection functions can be added without changing the existing equipment.

[0048] The energy storage voltage regulator provided in this embodiment for high-power multi-motor servo systems can achieve the goals of reducing energy consumption and heat load, and improving reliability. By rationally recovering, utilizing and discharging energy, it reduces unnecessary energy loss and heat generation, thereby improving stable operation and service life.

[0049] The energy storage voltage regulator provided in this embodiment for high-power multi-motor servo systems can ensure the stability of the bus voltage while recovering energy, and also take into account the feasibility of engineering deployment.

[0050] Example 2 The control method for an energy storage voltage regulator for a high-power multi-motor servo system provided in this embodiment is applicable to the energy storage voltage regulator for a high-power multi-motor servo system provided in Embodiment 1, including: S1: After power-on, perform soft-start pre-charge to establish common DC bus voltage. .

[0051] S2: Real-time data acquisition , and , Estimate the state of charge (SOC) of the energy storage unit.

[0052] The method for estimating the state of charge (SOC) of an energy storage unit is common in existing battery management systems (BMS), and it uses the ampere-hour integration method.

[0053] S3: When detected Furthermore, when the SOC is not saturated, the bidirectional Buck-Boost converter is controlled to enter the feedback absorption mode, and the bus feedback energy is transferred to the energy storage unit in a current-limiting manner.

[0054] When controlling a bidirectional Buck-Boost converter to enter feedback absorption mode, quantitative control based on SOC, bus voltage, and current limits is required. First, when SOC is less than the upper limit of SOC (For example, 90%) and SOC is greater than the lower limit of SOC. (For example, at 20%), energy feedback is allowed; Then, if the common DC bus voltage (For example, 400V), activate the feedback mode and limit the feedback current to its maximum value through current limiting control. (For example, within 10A), the feedback energy can be calculated using the following formula to ensure that energy is transferred to the energy storage unit at a safe rate: ; in, It represents the return of energy. This indicates the end time of the energy feedback calculation (i.e., the duration of the feedback from the start time 0 to the current time). This represents the instantaneous feedback current absorbed by the bidirectional Buck-Boost converter from the common DC bus side and fed into the energy storage branch at time t in the feedback absorption mode (taking the positive direction as "bus → energy storage"). when or When the feedback mode is interrupted, the feedback mode will be stopped.

[0055] The specific values ​​need to be adjusted based on experience.

[0056] S4: When detected And the SOC is higher than the lower limit of SOC. When the bidirectional Buck-Boost converter is in operation, it enters the bus support mode to send the stored energy back to the bus to suppress voltage drops.

[0057] Steps S3 and S4 employ current closed-loop control, with the charging and discharging current reference value determined by the bus voltage deviation. Generated via proportional-integral or droop control, and current limiting and slope limiting are set to reduce bus ripple. The target reference value (regulation setting / expected value) for the common DC bus voltage is the voltage level that the controller wants to regulate and maintain stably at. This target reference value is usually set based on constraints such as the rated DC bus voltage of the main driver, the allowable operating range of the bus voltage, and the voltage tolerance margin of the devices, and is used as a reference for the bus voltage deviation.

[0058] S5: When In and During this period, the bidirectional Buck-Boost converter is controlled to enter standby or low-power maintenance mode.

[0059] To optimize the control strategy of the bidirectional Buck-Boost converter, reasonable voltage and current thresholds need to be set when entering standby mode or low-power sustain mode.

[0060] Voltage threshold (first threshold) Set as the minimum charging voltage for the energy storage unit and maximum charging voltage Average value: This ensures that the bidirectional Buck-Boost converter enters low-power operation when the energy storage unit voltage is close to the middle value, avoiding overcharging or over-discharging.

[0061] Current threshold Then set to the maximum charging current of the energy storage unit. 20%-30% is used to limit the current in low-power sustain mode: ,in, To maintain the mode current ratio.

[0062] When the common DC bus voltage is close to And when the current is close to 0, it enters standby mode; while when the common DC bus current is lower than When the voltage and current thresholds are set, the converter enters a low-power sustain mode. By using these quantized voltage and current thresholds, the bidirectional Buck-Boost converter can enter a low-power state under appropriate conditions, thereby optimizing energy efficiency and stability.

[0063] S6: When Greater than the safety threshold In the event of energy storage saturation or a bidirectional Buck-Boost converter failure, the control braking chopper and braking resistor unit are activated to discharge energy using the braking resistor to limit energy loss. No more than .

[0064] The method for setting the safety threshold is as follows: First, identify all components that will be damaged / triggered by bus voltage, list their maximum withstand limits, take the smallest one as the base limit, and then deduct a certain margin. ; in, DC bus overvoltage protection trigger value for main motor driver / energy storage motor driver (settable value in manufacturer's manual or parameters); This is the maximum permissible operating voltage of the bus capacitor (considering rated withstand voltage and derating under temperature rise and ripple). This is the maximum allowable voltage for devices such as brake choppers (IGBT / MOSFET) and high-voltage side devices of Buck-Boost (device withstand voltage minus design margin). For safety margin, it is used to cover transient overshoot caused by bus voltage ripple, sampling error, control delay, and sudden changes in regenerative energy.

[0065] When quantifying energy storage unit saturation and converter failure, and activating the control logic of braking chopper and braking resistor unit, it is necessary to set reasonable thresholds based on parameters such as voltage, current and power.

[0066] First, the saturation threshold of the energy storage unit It is determined based on the maximum charging voltage of the energy storage unit. Reaching or exceeding its maximum charging voltage When the energy storage unit is considered saturated, to prevent overcharging, excess energy needs to be released through a braking chopper and braking resistor unit. The formula for determining energy storage unit saturation is: , When the voltage of the energy storage unit reaches or exceeds the maximum charging voltage, the braking chopper and braking resistor unit should be activated to release excess energy.

[0067] Secondly, faults in bidirectional Buck-Boost converters are primarily diagnosed by monitoring the current and voltage of the bidirectional Buck-Boost converter. When the output current of the bidirectional Buck-Boost converter Exceeding the maximum current of the energy storage unit If an overcurrent fault occurs, the braking chopper and braking resistor unit should be activated to discharge energy. The formula for this determination is: ; When the output voltage of the bidirectional Buck-Boost converter Exceeding the maximum charging voltage of the energy storage unit If an overvoltage fault occurs, the braking chopper and braking resistor units should be activated to prevent further damage. The formula for determining an overvoltage fault is: .

[0068] Finally, the calculation formulas for the discharge power of the braking chopper and braking resistor unit are used to determine the power that the braking resistor needs to release when the energy storage unit saturates or the bidirectional Buck-Boost converter fails. The discharge power is... It can be calculated using the following formula: ; in, It is the voltage of the common DC bus. This is the resistance value of the braking resistor. This formula ensures that when the energy storage unit is saturated or the converter fails, excess energy can be safely released through the braking resistor, avoiding damage due to overcharging or overvoltage.

[0069] Through these quantified thresholds and control logic, excess energy can be released in a timely manner when the energy storage unit is saturated or the converter fails, thereby ensuring safety and stability.

[0070] S7: Records energy flow and critical status and reports to the host computer to achieve monitoring and alarm.

[0071] The control method for energy storage regulators for high-power multi-motor servo systems provided in this embodiment is based on bus voltage threshold and supercapacitor state estimation. It coordinates the switching of bidirectional converters between operating modes such as feedback absorption, bus support, and current-limited charging and discharging, and triggers braking chopping to suppress bus overvoltage when energy storage is saturated or in case of fault.

[0072] The control method for energy storage voltage regulators for high-power multi-motor servo systems provided in this embodiment can achieve energy recovery, bus voltage regulation and safety protection without changing the structure of the main driver, reduce braking resistor energy consumption, and improve energy efficiency and reliability.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An energy storage voltage regulator for high-power multi-motor servo systems, characterized in that, It includes a main motor driver, an energy storage motor driver, a braking chopper and braking resistor unit, a controller, and a rectifier, a soft starter circuit, and a common DC bus connected in sequence. A bidirectional buck-boost converter is installed on the common DC bus, and the high-voltage side of the bidirectional buck-boost converter is connected in parallel to the positive and negative bus terminals of the common DC bus. The low-voltage side of the bidirectional buck-boost converter is connected to an energy storage unit. The input terminal of the main motor driver is connected in parallel to the positive and negative bus terminals of the common DC bus, and the output terminal of the main motor driver is connected to the main motor. The input terminal of the energy storage motor driver is connected in parallel to the positive and negative bus terminals of the common DC bus, and the output terminal of the energy storage motor driver is connected to the energy storage motor. The two ends of the braking chopper and braking resistor unit are connected across the positive and negative bus terminals of the common DC bus. The controller is used to control the charging and discharging power of the bidirectional buck-boost converter and to control the conduction of the braking chopper and braking resistor unit.

2. The energy storage voltage regulator for high-power multi-motor servo systems as described in claim 1, characterized in that, The controller is used to control the bidirectional buck-boost converter to enter the feedback absorption mode when the common DC bus voltage is higher than the first threshold and the energy storage unit is not saturated with charge.

3. The energy storage voltage regulator for high-power multi-motor servo systems as described in claim 1, characterized in that, The controller is used to control the bidirectional buck-boost converter to enter the bus support mode when the common DC bus voltage is lower than the second threshold and the state of charge of the energy storage unit is higher than the lower limit.

4. The energy storage voltage regulator for high-power multi-motor servo systems as described in claim 1, characterized in that, The controller is used to control the bidirectional buck-boost converter to enter standby mode when the difference between the common DC bus voltage and the first threshold is less than a set value and the common DC bus current is 0.

5. The energy storage voltage regulator for high-power multi-motor servo systems as described in claim 2 or 4, characterized in that, The first threshold is the average of the minimum and maximum charging voltages of the energy storage unit.

6. The energy storage voltage regulator for high-power multi-motor servo systems as described in claim 1, characterized in that, The controller is used to control the bidirectional buck-boost converter to enter the current-limiting maintenance mode when the common DC bus current is less than the current threshold, and the current threshold is positively correlated with the maximum charging current of the energy storage unit.

7. The energy storage voltage regulator for high-power multi-motor servo systems as described in claim 1, characterized in that, The controller is used to trigger the braking chopper and braking resistor unit to conduct when the energy storage unit voltage reaches the energy storage unit saturation threshold or when a bidirectional buck-boost converter fault is detected, so as to limit the common DC bus voltage from not exceeding the safety threshold.

8. The energy storage voltage regulator for high-power multi-motor servo systems as described in claim 7, characterized in that, The faults of the bidirectional buck-boost converter include: when the output current of the bidirectional buck-boost converter exceeds the maximum current of the energy storage unit, it is judged as an overcurrent fault; when the output voltage of the bidirectional buck-boost converter exceeds the maximum charging voltage of the energy storage unit, it is judged as an overvoltage fault.

9. The energy storage voltage regulator for high-power multi-motor servo systems as described in claim 1, characterized in that, The braking chopper and braking resistor unit includes an energy storage braking converter control system, a voltage comparator, a braking resistor, and a power switching device. The input terminal of the energy storage braking converter control system is connected to the output terminal of the bidirectional buck-boost converter. The voltage comparator is connected to the output terminal of the energy storage braking converter control system and the output terminal of the bidirectional buck-boost converter. The braking resistor is connected to the input terminal of the bidirectional buck-boost converter through the power switching device.

10. A control method for an energy storage voltage regulator for a high-power multi-motor servo system, characterized in that, An energy storage voltage regulator suitable for high-power multi-motor servo systems as described in any one of claims 1-9, comprising: Obtain the common DC bus voltage and energy storage unit voltage; Based on the common DC bus voltage and the energy storage unit voltage, the charging and discharging power of the bidirectional buck-boost converter is controlled, and the conduction of the braking chopper and braking resistor unit is also controlled.

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