energy storage converter

Abstract

The utility model provides a kind of energy storage converter, comprising: multiple power modules, each power module includes microcontroller and power unit, microcontroller is used to drive power unit to realize power conversion;Port circuit, port circuit is connected with each power module by power line, for realizing the input / output of power;Control circuit, control circuit is connected with each power module by communication line, control circuit is connected with direct current port circuit and alternating current port circuit by hard wire or communication line, control circuit is used to transmit control instruction to power module to realize power conversion.The utility model adopts two-level control architecture of one master and multiple slaves, realizes the reasonable distribution of controller resource overhead, and then the power expansion of multiple specifications products can be realized, and development and maintenance cost is also lower, convenient for the modularization extension of power, and each power module uses independent drive, eliminates the problem of uneven current, uneven heat dissipation, circulating current.

Description

Technical Field

[0001] This utility model relates to the field of power electronics technology, specifically to an energy storage converter. Background Technology

[0002] Currently, high-power energy storage converters typically employ power modules. These modules contain multiple IGBTs (Insulated Gate Bipolar Transistors) or MOSFETs (Metal-Oxide Semiconductor Field Effect Transistors), packaged in the same housing through parallel and series connections. For even higher power outputs, parallel connections of power modules are sometimes used. Therefore, driving these power modules requires numerous PWM (Pulse Width Modulation) control signals. For example, using two power modules in parallel in a three-phase diode-clamped three-level inverter requires 2 × 4 × 3 = 24 PWM control signals.

[0003] In related technologies, the driving of power modules mostly adopts a single-level architecture with a single controller. The number of PWM drives and current sampling channels is large, and the resource overhead of the controller is very large. Existing conventional commercial control chips cannot meet the control performance requirements and do not have the conditions for modular expansion. Furthermore, under a unified drive, multiple power modules connected in parallel will cause problems such as uneven current, uneven heat dissipation, and circulating current in each power device on the parallel branch. Utility Model Content

[0004] To solve the above-mentioned technical problems, this utility model provides an energy storage converter.

[0005] The technical solution adopted in this utility model is as follows: This utility model proposes an energy storage converter, comprising: multiple power modules, each power module including a microcontroller and a power unit, the microcontroller being used to control the power unit to achieve power conversion; a port circuit, the port circuit being connected to each power module via a power line, for realizing power input / output; and a control circuit, the control circuit being connected to each power module via a communication line, the control circuit being connected to the port circuit via a hard wire or a communication line, the control circuit being used to transmit control commands to the power modules to achieve power conversion.

[0006] The energy storage converter described above in this utility model also has the following additional technical features: Specifically, the control circuit includes: a DC voltage sampling circuit, a grid current sampling circuit, and a grid voltage sampling circuit; a communication controller, which is used to receive external control commands and provide feedback on the operating status of the energy storage converter; and a power controller, which is connected to the communication controller, the microcontroller, the DC voltage sampling circuit, the grid current sampling circuit, and the grid voltage sampling circuit. The power controller is used to generate a general control command based on the voltage and current information collected by the DC voltage sampling circuit, the grid current sampling circuit, and the grid voltage sampling circuit, and the control command received by the communication controller, and transmit it to the microcontroller so that the microcontroller generates a PWM drive signal according to the general control command to control the power unit to achieve power conversion.

[0007] Specifically, the power unit includes: an inverter unit, which includes a group of switching devices and interconnection circuits for power conversion; a power inductor, one of which is connected to the output terminal of one bridge arm of the inverter unit; a current sensor for detecting the real-time current of each power inductor; an isolation sampling circuit, which is connected to the current sensor and a microcontroller, and processes the real-time current of the power inductors collected by the current sensor before sending it to the microcontroller, so that the microcontroller generates a PWM drive signal based on the processed real-time current of the power inductors; and an isolation drive circuit, which is connected to the microcontroller and the inverter unit, and drives the switching devices of the inverter unit to achieve power conversion according to the PWM drive signal.

[0008] Furthermore, the switching device is a single-transistor IGBT or MOSFET.

[0009] Furthermore, the port circuit includes: a DC port circuit for DC power input; a DC link capacitor for stabilizing the DC bus voltage; and an AC port circuit for AC power output.

[0010] Specifically, the input terminal of the inverter unit is provided with a first capacitor and a second capacitor connected in series.

[0011] The beneficial effects of this utility model are: This utility model adopts a two-level control architecture with one master and multiple slaves to achieve reasonable allocation of controller resource overhead, thereby enabling power expansion of various product specifications. It also has low development and maintenance costs, facilitates modular expansion of power, and each power module adopts independent drive to eliminate problems such as uneven current, uneven heat dissipation, and circulating current. Attached Figure Description

[0012] Figure 1This is a schematic diagram of the structure of an energy storage converter according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of an energy storage converter according to another embodiment of the present invention; Figure 3 This is a topological schematic diagram of an inverter unit according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a filter according to an embodiment of the present invention. Detailed Implementation

[0013] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0014] Figure 1 This is a schematic diagram of the structure of an energy storage converter according to an embodiment of the present invention, as shown below. Figure 1 As shown, the energy storage converter includes: multiple power modules 1 ( Figure 1 (Taking 3 as an example), port circuit 2 and control circuit 3.

[0015] Each power module 1 includes a microcontroller 11 and a power unit 12. The microcontroller 11 is used to control the power unit 12 to achieve power conversion. The port circuit 2 is connected to each power module 1 through a power line and is used to realize power input / output. The control circuit 3 is connected to each power module 1 through a communication line. The control circuit 3 is connected to the port circuit 2 through a hard wire or a communication line and is used to transmit control commands to the power module 1 to achieve power conversion.

[0016] Specifically, such as Figure 1As shown, this utility model proposes a novel, modularly expandable two-level control architecture energy storage converter, comprising a control circuit 3, multiple (2, 3, 4…) identical power modules 1, and port circuits 2. The control circuit 3 acts as the master controller, communicating with the multiple power modules 1 to transmit control and feedback commands. The control circuit 3 and port circuits 2 are connected via hardwires and signal lines, respectively. Each power module 1 is connected to the port circuit 2 via a power line. The communication methods include, but are not limited to, one or more combinations of SPI (Serial Peripheral Interface), SCI (Serial Communication Interface), and fiber optics. Each power module 1 is driven by a separate microcontroller as a slave controller. The control circuit 3 generates a general control command based on the collected voltage and current information and control commands, and transmits it to the microcontroller 11. The microcontroller 11 receives the general control command from the control circuit 3 and the detected output current of the power unit, generating a corresponding PWM drive signal to the corresponding power unit 12, thereby driving the power unit 12 to perform the basic switching action of power conversion. The power conversion can be rectification or inversion. The microcontroller 11 includes, but is not limited to, small DSPs (Digital Signal Processing), FPGAs (Field Programmable Gate Arrays), CPLDs (Complex Programmable Logic Devices), and other control chips suitable for power electronic drive control, as well as the loaded control software.

[0017] Therefore, this utility model adopts a two-level control architecture with one master and multiple slaves, and uses a mature, commercially available, low-cost small-scale controller to achieve a reasonable allocation of controller resource overhead. This enables power expansion for various product specifications, and the development and maintenance costs are also low. It facilitates modular expansion of power, and each power module is driven independently, eliminating problems such as uneven current, uneven heat dissipation, and circulating current.

[0018] In one embodiment of this utility model, such as Figure 2 As shown, the control circuit 3 includes: a DC voltage sampling circuit 31, a grid current sampling circuit 32, a grid voltage sampling circuit 33, a communication controller 34, and a power controller 35.

[0019] The communication controller 34 is used to receive external control commands and feedback the operating status of the energy storage converter. The power controller 35 is connected to the communication controller 34, the microcontroller 11, the DC voltage sampling circuit 31, the grid current sampling circuit 32, and the grid voltage sampling circuit 33. The power controller 35 is used to generate a general control command based on the voltage and current information collected by the DC voltage sampling circuit 31, the grid current sampling circuit 32, and the grid voltage sampling circuit 33, and the control command received by the communication controller 34. The general control command is then transmitted to the microcontroller 11 so that the microcontroller 11 generates a PWM drive signal based on the general control command to control the power unit 12 to achieve power conversion.

[0020] Specifically, the power controller 35 can be a control chip suitable for power electronic drive control, such as a DSP, FPGA, or CPLD, along with its loaded control software; the communication controller 34 includes various types of control chips, such as an ARM (Advanced RISC Machine, RISC microprocessor) architecture uC controller (a type of PWM controller), and its loaded control software. The power controller 35 and the communication controller 34 communicate to transmit the required information, regardless of the specific communication method used. The DC voltage sampling circuit 31, the mains current sampling circuit 32, and the mains voltage sampling circuit 33 transmit the collected voltage and current information to the power controller 35 for power regulation.

[0021] In one embodiment of this utility model, such as Figure 2 As shown, the power unit 12 includes: an inverter unit, a power inductor, a current sensor, an isolation sampling circuit, and an isolation drive circuit.

[0022] The inverter unit includes a group of switching devices and interconnection circuits for power conversion. One power inductor is connected to the output of one bridge arm of the inverter unit. An isolation sampling circuit is used to detect the real-time current of each power inductor. The isolation sampling circuit is connected to the current sensor and the microcontroller 11. The isolation sampling circuit processes the real-time current of the power inductor collected by the current sensor and sends it to the microcontroller 11 so that the microcontroller 11 can generate a PWM drive signal based on the processed real-time current of the power inductor. The isolation drive circuit is connected to the microcontroller 11 and the inverter unit. The isolation drive circuit drives the switching devices of the inverter unit to achieve power conversion according to the PWM drive signal.

[0023] Specifically, the isolation sampling circuit, current sensor, and isolation drive circuit are only shown as one path for ease of illustration. In reality, there are multiple isolation drive circuits and three current sensors and isolation sampling circuits in the three-phase bridge arm. The inverter unit can be a three-level inverter unit or a two-level half-bridge inverter, and the number of isolation drive circuits corresponds accordingly.

[0024] In one embodiment of this invention, the switching device is a single-transistor IGBT or MOSFET. Therefore, using a single-transistor power device enables high-power converter power integration, while also significantly reducing the size and cost of magnetic components.

[0025] In one embodiment of this utility model, such as Figure 3 As shown, the input terminal of the inverter unit is equipped with a first capacitor Ct and a second capacitor Cb connected in series.

[0026] Specifically, such as Figure 3 As shown, the system includes a first capacitor Ct, a second capacitor Cb, power switches (Sa1-Sa4, Sb1-Sb4, Sc1-Sc4), power diodes (Da1-Da6, Db1-Db6, Dc1-Dc6), current sensors detecting currents ia, ib, and ic, and power inductors La, Lb, and Lc. The power units (Sa1-Sa4, Sb1-Sb4, Sc1-Sc4) receive drive signals from the microcontroller 11 to achieve AC / DC or DC / AC power conversion. The current sensors output current signals ia, ib, and ic to the isolation sampling circuit, and the power inductors are used to store and release energy for the switching devices.

[0027] Inverter units can be connected in an interleaved parallel configuration, thereby expanding the capacity of power devices that need to be connected in parallel and solving the problems of uneven current and uneven losses. The power units and inverter units within each power module are driven independently and receive unified scheduling control from the control circuit. Independent carrier phase control, carrier in-phase control, or carrier phase-shift control can be adopted according to actual engineering needs.

[0028] In one embodiment of this utility model, the port circuit 2 includes: a DC port circuit 21, a DC link capacitor 22, and an AC port circuit 23. The DC port circuit 21 is used for DC power input; the DC link capacitor 22 is used to stabilize the DC bus voltage; and the AC port circuit 23 is used for AC power output.

[0029] Specifically, the DC port circuit 21 includes a DC input interface, filtering, protection, and pre-charging circuit; the DC link capacitor 22 includes a bus capacitor, a multilayer bus, and a discharge circuit; and the AC port circuit 23 includes filtering, protection, pre-charging, and output interface circuits. Together with the power module 1, the port circuit 2 realizes the power conversion and basic rectification / inversion functions of the converter.

[0030] This embodiment also provides a structural form of an AC output filter, such as... Figure 4As shown, the output terminals of the power inductors La1, La2, and La3 in the three power modules are connected in parallel and then connected to the capacitor Cfa and the grid-side inductor Lga to form the A-phase AC output filter circuit of the inverter unit. The output terminals of Lb1, Lb2, and Lb3 are connected in parallel and then connected to the capacitor Cfb and the grid-side inductor Lgb to form the B-phase AC output filter circuit of the inverter unit. The output terminals of Lc1, Lc2, and Lc3 are connected in parallel and then connected to the capacitor Cfc and the power frequency inductor Lgc to form the C-phase AC output filter circuit of the inverter unit. The advantages of this design are that the power inductors La1, La2, and La3 are separate units with large inductance and small current, resulting in lower cost, smaller size, and lower ripple, while the grid-side inductors Lga, Lgb, and Lgc are integrated units with small inductance and large current, offering even better cost and size.

[0031] Figure 4 In the diagram, Grid_A, Grid_B, and Grid_C represent the A, B, and C phases of the inverter unit, respectively. A1 drives Driver_A1, which includes Driver_Sa1_1 to Driver_Sa1_4, and supplies power to the switching transistors Sa1_1 to Sa1_4 respectively. B1 drives Driver_B1, which includes Driver_Sb1_1 to Driver_Sb1_4, and supplies power to the switching transistors Sb1_1 to Sb1_4 respectively. C1 drives Driver_C1, which includes Driver_Sc1_1 to Driver_Sc1_4, and supplies power to the switching transistors Sc1_1 to Sc1_4 respectively. Similarly, A2 drives Driver_A2, B2 drives Driver_B2, C2 drives Driver_C2, and A3 drives Driver_A3, B3 drives Driver_B3, and C3 drives Driver_C3. These are controlled by the microcontrollers within the other two power modules and, after isolation and power amplification, are supplied to the corresponding switching transistors; these details will not be repeated here.

[0032] Driver_S[a..c][1..4] represents the driving waveforms of the first to fourth transistors of the A, B, and C phase modulation outputs of the three-level inverter unit. Their timing is determined according to the specific three-level inverter unit structure. The start times of Driver_Sa1_1, Driver_Sa2_1…Driver_San_1 are ta0, ta0+T / n, ta0+2*T / n…ta0+(n-1)*T / n respectively; the start times of Driver_Sb1_1, Driver_Sb2_1…Driver_Sbn_1 are tb0, tb0+T / n, tb0+2*T / n…tb0+(n-1)*T / n respectively; and the start times of Driver_Sc1_1, Driver_Sc2_1…Driver_Sac_1 are tc0, tc0+T / n, tc0+2*T / n…tc0+(n-1)*T / n respectively, where n is an integer greater than or equal to 2, ta0, tb0, and tc0 are the carrier start times of phases A, B, and C respectively, and T is the power frequency period of 20ms.

[0033] In summary, the energy storage converter according to the embodiment of this utility model adopts a two-level control architecture with one master and multiple slaves, which realizes the reasonable allocation of controller resource overhead, thereby enabling power expansion of various product specifications, and the development and maintenance costs are also low. It is convenient for modular expansion of power, and each power module adopts independent drive, eliminating problems such as uneven current, uneven heat dissipation, and circulating current.

[0034] In the description of this utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0035] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to 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 utility model according to the specific circumstances.

[0036] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0037] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An energy storage converter, characterized in that, include: Multiple power modules, each power module including a microcontroller and a power unit, wherein the microcontroller is used to control the power unit to achieve power conversion; Port circuits, which are connected to each power module via power lines, are used to realize power input / output; A control circuit is provided, which is connected to each of the power modules via a communication line. The control circuit is also connected to the port circuit via a hard wire or a communication line. The control circuit is used to transmit control commands to the power modules to achieve power conversion.

2. The energy storage converter according to claim 1, characterized in that, The control circuit includes: DC voltage sampling circuit, mains current sampling circuit, and mains voltage sampling circuit; The communication controller is used to receive external control commands and provide feedback on the operating status of the energy storage converter. A power controller is connected to the communication controller, the microcontroller, the DC voltage sampling circuit, the grid current sampling circuit, and the grid voltage sampling circuit. The power controller is used to generate a general control command based on the voltage and current information collected by the DC voltage sampling circuit, the grid current sampling circuit, and the grid voltage sampling circuit, and the control command received by the communication controller. The general control command is then transmitted to the microcontroller, so that the microcontroller generates a PWM drive signal based on the general control command to control the power unit to achieve power conversion.

3. The energy storage converter according to claim 1, characterized in that, The power unit includes: An inverter unit, comprising a group of switching devices and interconnection circuits, is used to realize power conversion; A power inductor, one power inductor being connected to the output terminal of one bridge arm of the inverter unit; A current sensor is used to detect the real-time current of each of the power inductors; An isolation sampling circuit is connected to the current sensor and the microcontroller. The isolation sampling circuit is used to process the real-time current of the power inductor collected by the current sensor and send it to the microcontroller so that the microcontroller can generate a PWM drive signal based on the processed real-time current of the power inductor. An isolation drive circuit is provided, which is connected to the microcontroller and the inverter unit. The isolation drive circuit is used to drive the switching devices of the inverter unit to achieve power conversion according to the PWM drive signal.

4. The energy storage converter according to claim 3, characterized in that, The switching device is a single-transistor IGBT or MOSFET.

5. The energy storage converter according to claim 1, characterized in that, The port circuit includes: DC port circuit for DC power input; DC link capacitors are used to stabilize the DC bus voltage. AC port circuit, used for AC power output.

6. The energy storage converter according to claim 1, characterized in that, The input terminal of the inverter unit is equipped with a first capacitor and a second capacitor connected in series.

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