Isolation type parallel operation circuit suitable for household energy storage PCS

Abstract

The utility model discloses an isolation type parallel operation circuit suitable for a household energy storage PCS. The isolation type parallel operation circuit comprises an operational amplifier module, an isolation linear optocoupler module, a post-stage operational amplifier module, an EMI circuit module, a current sharing signal feedback module and a DSP module. Electrical isolation between external parallel operation signals and the DSP is achieved through the isolation linear optocoupler module, direct influences of interference signals and electrostatic impact on the DSP module are blocked, and the anti-interference capacity and the operation reliability of the system are remarkably improved. The current-sharing signal feedback module realizes high-precision voltage division and conversion of a current-sharing signal through collaborative design of a series resistor and a current sampling circuit, real-time signal processing and adjustment are carried out in combination with the DSP module, the DSP operation burden is reduced, and the current-sharing precision and efficiency are improved. And the EMI circuit module is matched with the shielding wire, so that interference is shielded and filtered in a multi-layer manner from a signal source to a transmission process, and the stability of signal transmission is ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of family energy storage, especially to an isolation type parallel machine circuit suitable for family energy storage PCS. BACKGROUND

[0002] The family energy storage PCS (power conversion system) is a core device widely used in the field of family energy storage. Its main function is to realize the bidirectional conversion of energy between the energy storage device and the power grid, and support multiple devices to run in parallel to meet the demand for greater energy output. In the process of multi-machine parallel operation, it is necessary to achieve dynamic balance of the load current of multiple devices through current sharing control to ensure the stability and safety of system operation. However, the collection, processing and transmission of current sharing control signals face many challenges in the prior art.

[0003] In the prior art, in order to realize multi-machine current sharing, the common practice is to lead out the current sharing signal and directly connect it with the DSP (digital signal processor) module, so as to adjust the load current in real time. Although this design can achieve basic current sharing control, it has the following shortcomings in actual application:

[0004] 1. Poor anti-interference ability: The current sharing signal is directly connected with the DSP module, and the signal transmission process is easily affected by external electromagnetic interference and electrostatic shock, causing system restart or damage. Especially in complex electromagnetic environment, the stability of system operation is difficult to guarantee.

[0005] 2. Difficulty in electrostatic protection: The direct signal connection method requires high protection against static electricity, and additional protection circuit is needed, which not only increases the design complexity, but also may lead to cost increase. Even if the protection circuit is added, electrostatic shock may still be transmitted to the DSP module through the signal line, causing system performance degradation.

[0006] 3. Low reliability: Since the signal connection method is highly sensitive to external environment, when multiple devices are running in parallel, the fluctuation of signal transmission may cause unbalanced load current, further exacerbating the instability of the system and the risk of device damage.

[0007] In order to improve the above problems, the prior art usually adopts the method of processing the current sharing signal through software algorithm, trying to improve the anti-interference ability of the system in a digital way. However, this pure software current sharing control scheme still has the following shortcomings, such as high dependence of software processing on the computing ability of DSP module, increasing the computing burden and possibly causing real-time problems, especially when a large number of devices are running in parallel, the signal processing delay will affect the accuracy of current sharing control; it is difficult to completely solve the influence of external interference on signal collection and transmission by relying solely on software algorithm, and the system is still prone to current sharing failure in high interference environment.

[0008] Therefore, how to realize high-precision current sharing control in parallel operation of multiple energy storage PCS devices, and improve the anti-interference ability and reliability of the system, becomes a technical problem to be solved by the utility model. Utility model content

[0009] The utility model solves the technical problem in the prior art, provides an isolated parallel operation circuit suitable for household energy storage PCS, to solve the problems of poor anti-interference ability of current sharing signal, heavy DSP calculation burden and low system reliability in the background art.

[0010] To solve the above technical problems, the utility model takes the technical scheme as follows:

[0011] An isolated parallel operation circuit suitable for household energy storage PCS, comprising:

[0012] An operational amplifier module is used for amplifying the collected local load current signal and outputting;

[0013] An isolated linear optocoupler module is connected with the output end of the operational amplifier module, is used for receiving the output signal of the operational amplifier module, and outputs the signal after electrical isolation between the input end and the output end;

[0014] A rear-stage operational amplifier module is connected with the output end of the isolated linear optocoupler module, is used for amplifying and enhancing the isolated signal;

[0015] An EMI circuit module is connected with the output end of the rear-stage operational amplifier module, is used for carrying out electromagnetic interference filtering processing on the amplified signal, and is connected with the signal input end of the external energy storage PCS device through electrical connection;

[0016] A current sharing signal feedback module comprises a series resistor and a current sampling circuit, the series resistor is electrically connected with the output end of the EMI circuit module, the current sampling circuit is used for sampling the current signal of multiple PCS through the series resistor and the current sampling circuit, carrying out current sharing processing on the sampled current signal to realize average current distribution, and being electrically connected with the input end of the DSP module through electrical connection;

[0017] A DSP module is connected with the output end of the current sharing signal feedback module, is used for receiving the current sharing current signal and adjusting the load current output.

[0018] As a further scheme of the utility model, the isolation linear optical coupling module includes an electrical isolation structure, the electrical isolation structure includes a photosensitive receiving unit and a light signal transmitting unit, and the photosensitive receiving unit and the light signal transmitting unit are respectively located between the input end and the output end of the isolation linear optical coupling module and are used for realizing signal isolation of the input end and the output end through light signals.

[0019] As a further scheme of the utility model, the series resistance of the current sharing signal feedback module includes a plurality of groups of resistors with the same resistance value, each group of resistors is uniformly distributed in the current sampling circuit, and is used for realizing accurate voltage division of the current sharing signal.

[0020] As a further scheme of the utility model, the EMI circuit module includes an input filter unit and an output filter unit, the input filter unit is connected with the output end of the later-stage operational amplifier module, and the output filter unit is connected with the input end of the current sharing signal feedback module.

[0021] As a further scheme of the utility model, the later-stage operational amplifier module includes one feedback resistor and two operational amplifiers, the feedback resistor is connected between the two operational amplifiers, and is used for adjusting the amplification multiple to adapt to the signal input requirement of the DSP module.

[0022] As a further scheme of the utility model, the operational amplifier module is a differential amplifier, the differential amplifier has the advantages of being capable of suppressing common-mode interference, and the input end of the differential amplifier is connected with the positive and negative output ends of the local load current sampling circuit.

[0023] As a further scheme of the utility model, the EMI circuit module is connected with the signal input end of the external energy storage PCS device through a shielding wire.

[0024] Compared with the prior art, the utility model has the beneficial effects that:

[0025] 1. The EMI circuit module and the differential operational amplifier are cooperatively designed, interference signals are shielded and filtered in multiple levels from a signal source to a transmission process, the stability of current sharing signal transmission is ensured, and efficient adaptation to a complex interference environment is realized.

[0026] 2. The electrical isolation structure of the isolation linear optical coupling module between the input end and the output end completely blocks interference and electrostatic risks of external parallel connection signal lines on the DSP module, solves inherent problems of poor anti-interference performance and electrostatic protection of a traditional direct signal connection mode, not only significantly improves the stability of system operation, but also avoids direct impact of external interference signals on the DSP module, and reduces the risk of equipment damage.

[0027] The additional aspects and advantages of the present application will be given in part in the following description, and will become apparent from the following description, or will be learned through practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0029] Figure 1 : current sharing signal acquisition principle diagram.

[0030] Figure 2 : isolation and current sharing signal feedback module flow chart.

[0031] Figure 3 : current sharing circuit principle diagram. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0033] Please refer to Figure 1 — Figure 3 In the embodiments of the present application, an isolation type parallel machine circuit suitable for household energy storage PCS comprises:

[0034] An operational amplifier module is used for amplifying the collected local load current signal and outputting; an isolation linear optocoupler module is connected to the output end of the operational amplifier module, used for receiving the output signal of the operational amplifier module, and outputting the signal after electrical isolation between the input end and the output end;

[0035] The back-stage operational amplifier module is connected with the output end of the isolated linear photo-coupler module, and is used for amplifying and enhancing the isolated signal; the EMI circuit module is connected with the output end of the back-stage operational amplifier module, and is used for carrying out electromagnetic interference filtering processing on the amplified signal, and is connected with the signal input end of the external energy storage PCS device through electrical connection; the current sharing signal feedback module comprises a series resistor and a current sampling circuit, the series resistor is electrically connected with the output end of the EMI circuit module, the current sampling circuit is used for sampling the current signals of the plurality of PCSs through the series resistor and the current sampling circuit, and carries out current sharing processing on the sampled current signals to realize average current distribution, and is electrically connected with the input end of the DSP module through electrical connection; the DSP module is connected with the output end of the current sharing signal feedback module, and is used for receiving the current sharing current signal and adjusting the load current output.

[0036] As a further scheme of the utility model, the isolated linear photo-coupler module includes an electrical isolation structure, and the electrical isolation structure includes a light-sensitive receiving unit and a light signal transmitting unit, the light-sensitive receiving unit and the light signal transmitting unit are respectively located between the input end and the output end of the isolated linear photo-coupler module for realizing signal isolation between the input end and the output end through light signals; the series resistor of the current sharing signal feedback module includes a plurality of resistors with the same resistance value, and each group of resistors is uniformly distributed in the current sampling circuit for realizing average current of the current signals of the plurality of PCSs through a hardware mode.

[0037] The EMI circuit module comprises an input filter unit and an output filter unit, the input filter unit is connected with the output end of the back-stage operational amplifier module, and the output filter unit is connected with the input end of the current sharing signal feedback module; the back-stage operational amplifier module comprises a feedback resistor and two operational amplifiers, the feedback resistor is connected between the two operational amplifiers, and is used for adjusting the amplification factor to adapt to the signal input requirement of the DSP module; the operational amplifier module is a differential amplifier, and the input end of the differential amplifier is connected with the positive and negative output ends of the local load current sampling circuit; the EMI circuit module is connected with the signal input end of the external energy storage PCS device through a shielded wire.

[0038] As shown in Figure 1 , the implementation mode of current sharing signal acquisition is shown. The load current of each device is divided by the series resistor in the sampling circuit, and a current sharing signal sampling point is formed. Through these sampling points, hardware average of the actual current of the plurality of devices can be realized, thereby providing data support for subsequent current sharing control. The current sharing design of the series resistor ensures high precision and consistency of signal acquisition, and realizes current average calculation at the hardware level, thereby liberating dsp resources. As shown in Figure 2As shown in FIG. 1, the signal processing flow of the entire current-sharing control circuit is shown. Starting from the collection of the load current signal, the signal is preliminarily amplified by an operational amplifier, and then the electrical isolation between the input and output is realized through a linear optical coupling. The isolated signal enters the post-stage operational amplifier for enhancement, ensuring the integrity and accuracy of the transmission signal. Subsequently, the signal enters the EMI circuit to complete multi-level shielding and filtering of electromagnetic interference. The processed signal is finally transmitted to the DSP, which calculates the average current of multiple devices according to the received signal and adjusts the output in real time to ensure the stability of the current-sharing operation of the parallel machines. As shown in FIG. 2, the hardware structure of the current-sharing circuit is shown. The entire circuit is composed of a load current collection module, a signal amplification module, an isolation module, a current-sharing signal feedback module, and a DSP control module. The voltage signal generated by the sampling circuit is sent to the isolation optical coupling module after being amplified by a first operational amplifier, realizing the electrical isolation of the signal and ensuring that the DSP is not affected by external interference. After the amplified signal passes through the EMI filter module to eliminate high-frequency interference, it is transmitted to the current-sharing signal feedback module. The current-sharing signal feedback module calculates the current-sharing error through the difference between the two current signals and sends the current-sharing adjustment signal to the DSP, completing the dynamic control of the output current of the parallel machine devices. This hardware current-sharing design significantly improves the anti-interference ability and reliability of the system. Figure 3

[0039] Example 1:

[0040] In the multi-machine parallel operation of the home energy storage PCS (power conversion system), load current sharing control is an important link to ensure system stability, device safety, and efficient energy utilization. In existing home energy storage systems, to meet the demand for greater power output, multiple PCS devices are usually operated in parallel. However, during parallel operation, the load currents of each device may be unbalanced due to differences in circuit characteristics, external interference, and other reasons, leading to overloading and even damage to some devices, and a decrease in overall system efficiency. Traditional technology directly connects the current-sharing signal to the DSP module to realize real-time adjustment of the load current, but this scheme faces problems such as poor anti-interference ability and low reliability.

[0041] The present embodiment provides a home energy storage PCS solution based on an isolated parallel circuit to solve the above problems in traditional technology and significantly improve the anti-interference ability and current-sharing stability of the system. The specific implementation is as follows:

[0042] ​The circuit comprises the following key modules: an operational amplifier module, an isolated linear optocoupler module, a post-stage operational amplifier module, an EMI circuit module, a current-sharing signal feedback module, and a DSP module. The specific implementation is described below in combination with the application scenarios and module functions: In actual applications, each energy storage PCS device acquires the load current signal in real time through its own current sampling circuit and inputs the signal to the operational amplifier module. The operational amplifier module differentially amplifies the acquired current signal to eliminate common-mode interference and ensure the high precision and stability of the signal. The amplified signal is output to the isolated linear optocoupler module. The isolated linear optocoupler module is a key innovative part in this embodiment. It realizes electrical isolation between the input and output through the transmission of optical signals. Specifically, the load current signal is converted into an optical signal by the optical signal transmitting unit, transmitted to the optical signal receiving unit, and then restored into an electrical signal for output. This isolation method completely blocks the static electricity and electromagnetic interference that may be introduced by external parallel connection signal lines, thereby avoiding the problem that the interference directly acts on the DSP module in the traditional scheme. The isolated signal is further amplified and enhanced by the post-stage operational amplifier module to ensure that there is no distortion in the signal transmission process. Subsequently, the signal enters the EMI circuit module, which filters the signal through a filter to eliminate high-frequency noise in the transmission process. The processed signal enters the current-sharing signal feedback module, which accurately divides the voltage through a series resistor and generates a feedback signal related to current sharing by the current sampling circuit, and finally outputs to the DSP module. The DSP module receives the output signal of the current-sharing signal feedback module and compares the local load current with the current-sharing signal through a real-time signal comparison algorithm. When an inconsistency is detected, the DSP module generates an adjustment signal to dynamically adjust the output current of the local device until the load current and the current-sharing signal are consistent. This closed-loop adjustment mechanism ensures the dynamic balance of the current of multiple energy storage PCS devices during operation.

[0043] In a typical home energy storage system, for example, the parallel operation scenario of three PCS devices is included: when the output current of a device is abnormal due to load fluctuation, the current-sharing signal feedback module immediately acquires and transmits the signal, and the DSP module quickly detects the inconsistency and adjusts the output current of the device. The electrical isolation of the isolated linear optocoupler module effectively avoids the interference of external electromagnetic interference and static electricity on the DSP signal processing, and the EMI circuit module further improves the stability of the signal. Through this multi-module collaborative design, the entire system realizes rapid response, significantly improves current-sharing stability, and significantly reduces the risk of device damage.

[0044] Embodiment 2:

[0045] In a small commercial energy storage system, the system is composed of multiple PCS devices and a set of battery modules, which is used to supply power to the load at peak electricity price and store electricity at off-peak electricity price. Multiple PCS devices of the system operate in parallel to meet higher power demand. However, due to the complex environment and large load fluctuation, the following problems are prone to occur in the traditional parallel connection scheme: insufficient current sharing control accuracy of the load current, system stability decline caused by electromagnetic interference, and insufficient real-time performance caused by excessive dependence on the computing power of the DSP. To solve these problems, an isolated parallel connection circuit is adopted in the embodiment, which combines an isolated linear optocoupler module and a hardware current sharing signal feedback module to optimize the parallel connection performance of multiple PCS devices.

[0046] For example, in an actual use scenario, when the system is running, the load current of each PCS device is collected in real time through the current sampling circuit of each PCS device. The current signal is preliminarily amplified by the operational amplifier module to eliminate the common-mode interference in the signal, and then transmitted to the isolated linear optocoupler module. The isolated linear optocoupler module realizes electrical isolation through optical signal transmission to ensure that the signal quality will not be affected by external electromagnetic interference or electrostatic shock during signal transmission.

[0047] The isolated signal is further amplified by the post-stage operational amplifier module and transmitted to the EMI circuit module. The EMI circuit module is composed of an input filter unit and an output filter unit, which filters out high-frequency interference in the signal to ensure the stability of the signal. The filtered signal enters the current sharing signal feedback module, which realizes accurate voltage division of the current sharing signal through a series resistor and generates a current sharing signal by the current sampling circuit; the current sharing signal is transmitted to the DSP module through electrical connection, and the DSP module dynamically adjusts the output current of the PCS device based on the comparison result of the received current sharing signal and the local load current, so that the load currents of each device remain consistent. Through this closed-loop control method, the system can realize real-time current sharing adjustment, and can maintain current sharing stability even in the case of rapid load fluctuation or strong external interference, significantly improving the parallel connection performance of multiple PCS devices in complex commercial energy storage scenarios, avoiding problems such as poor anti-interference performance, insufficient current sharing accuracy and system instability in traditional technologies, and providing reliable protection for efficient and stable energy storage system operation.

[0048] In the utility model, unless another definite provision and limitation, the terms "mount", "set", "connect", "fix", "screw" and so on should do the broad sense understanding, for example, can be fixed connection, also can be detachable connection, or be integrated, can be mechanical connection, also can be electrical connection, can be direct connection, also can pass through the indirect connection of intermediate medium, can be the communication of two element interiors or the interaction of two elements, unless another definite limitation, for the ordinary skilled person in the art, can understand the concrete meaning of the above terms in the utility model according to the specific situation.

[0049] It is apparent for a person skilled in the art that the present application is not limited to the details of the above-described exemplary embodiments, but that it can be implemented in other concrete forms without departing from the spirit or the essential characteristics of the present application. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, the scope of the present application being defined by the appended claims rather than the above description, and all changes coming within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. An isolated parallel circuit suitable for home energy storage PCS, characterized in that, include: The operational amplifier module is used to amplify and output the acquired local load current signal; An isolated linear optocoupler module, whose input terminal is connected to the output terminal of the operational amplifier module, is used to receive the output signal of the operational amplifier module and output the signal after electrical isolation between the input terminal and the output terminal; The input terminal of the post-operational amplifier module is connected to the output terminal of the isolated linear optocoupler module, and is used to amplify and enhance the isolated signal; An EMI circuit module, whose input terminal is connected to the output terminal of the subsequent operational amplifier module, is used to perform electromagnetic interference filtering on the amplified signal and is electrically connected to the signal input terminal of an external energy storage PCS device. The current sharing signal feedback module includes a series resistor and a current sampling circuit. The series resistor is electrically connected to the output terminal of the EMI circuit module. The current sampling circuit is used to sample the current signals of multiple PCS through the series resistor and the current sampling circuit, and to perform current sharing processing on the sampled current signals to achieve average current distribution. It is also electrically connected to the input terminal of the DSP module through an electrical connection. The DSP module, whose input is connected to the output of the current sharing signal feedback module, is used to receive the current signal of current sharing and adjust the load current output.

2. The isolated parallel circuit suitable for home energy storage PCS according to claim 1, characterized in that, The isolated linear optocoupler module includes an electrical isolation structure, which includes a photosensitive receiving unit and an optical signal transmitting unit. The photosensitive receiving unit and the optical signal transmitting unit are located between the input and output ends of the isolated linear optocoupler module, respectively, and are used to achieve signal isolation between the input and output ends through optical signals.

3. The isolated parallel circuit suitable for home energy storage PCS according to claim 1, characterized in that, The series resistor of the current sharing signal feedback module includes multiple sets of resistors with the same resistance value, and each set of resistors is evenly distributed in the current sampling circuit.

4. An isolated parallel circuit suitable for home energy storage PCS according to claim 1, characterized in that, The EMI circuit module includes an input filtering unit and an output filtering unit. The input filtering unit is connected to the output terminal of the subsequent operational amplifier module, and the output filtering unit is connected to the input terminal of the current sharing signal feedback module.

5. An isolated parallel circuit suitable for home energy storage PCS according to claim 1, characterized in that, The post-amplifier module includes a feedback resistor and two operational amplifiers, with the feedback resistor connected between the two operational amplifiers.

6. An isolated parallel circuit suitable for home energy storage PCS according to claim 5, characterized in that, The operational amplifier module is a differential amplifier, and the input terminal of the differential amplifier is connected to the positive and negative output terminals of the local load current sampling circuit.

7. An isolated parallel circuit suitable for home energy storage PCS according to claim 1, characterized in that, The EMI circuit module is connected to the signal input terminal of the external energy storage PCS device via shielded wires.

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