A power converter for AC / DC hybrid and a control method thereof

Abstract

The technical scheme of the present application is: a power converter and a control method thereof, comprising a switching module, a plurality of ports, a DC bus capacitor and a control analysis module; each port is provided with a switch; one end of the switching module is connected with the DC bus capacitor, and the other end is connected with the switch of each port; one end of the port is connected with a power supply or a load, and the other end is connected with the switch of the port; when the switch of any port is closed, the switches of other ports are opened; one side of the DC bus capacitor is connected with the ground, and the other side is connected with the switching module for energy exchange; the control analysis module is connected with the switches of each port and the switching module through a control line, and generates a driving signal of the switching module and the switches based on the power supply or the load connected with each port. The present application can output different forms of electric energy in time sequence.

Description

Technical Field

[0001] This invention belongs to the field of electrical technology, specifically relating to an AC / DC multiplexed power converter and its control method. Background Technology

[0002] The Energy Internet can be understood as a new type of power network that comprehensively utilizes advanced power electronics, information technology, and intelligent management technology to interconnect a large number of nodes in a new power network, consisting of distributed energy harvesting devices, distributed energy storage devices, and various types of loads, to achieve bidirectional energy flow and peer-to-peer energy exchange and sharing. From the perspective of government administrators, the Energy Internet is a new energy system architecture that is compatible with the traditional power grid, can fully, widely, and effectively utilize distributed renewable energy, and meets the diverse electricity needs of users. From the perspective of operators, the Energy Internet is an energy consumption market that can interact with consumers and is subject to competition; only by improving the quality of energy services can they win market competition. From the perspective of consumers, the Energy Internet not only possesses the power supply function of the traditional power grid but also provides a public energy exchange and sharing platform for various consumers.

[0003] When various types of energy devices are connected to the energy internet, energy conversion is required. Traditional controllers, when handling the connection of different types of energy devices, need to achieve efficient energy conversion through complex AC / DC analog conversion equipment or transformers. Furthermore, each conversion requires different equipment; for example, DC-DC conversion and DC-AC conversion, where the AC voltage, frequency, and phase may vary. To meet the needs of different electrical devices, the conversion system requires a large number and variety of power supplies, resulting in large device size, complex power supply schemes, increased system losses, and is detrimental to the stable operation of the entire system. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the aforementioned background technology and provide an AC / DC multiplexed power converter and its control method, which can output different forms of electrical energy in a time-sequential manner.

[0005] The technical solution adopted in this invention is as follows: an AC / DC multiplexed power converter, comprising a switching module, several ports, a DC bus capacitor, and a control and analysis module; each port is equipped with a switch; one end of the switching module is connected to the DC bus capacitor, and the other end is connected to the switch of each port; one end of each port is connected to a power source or load, and the other end is connected to the switch of that port; when the switch configured on any port is closed, the switches on other ports are open; one side of the DC bus capacitor is grounded, and the other side is connected to the switching module for energy exchange; the control and analysis module is connected to the switches and switching modules of each port through control lines, and is based on the connections of each port... The power supply or load generates drive signals for the switching module and the switch; the drive signals of the switching module are divided into multiple timing switching cycles according to the number of ports, and each timing switching cycle corresponds to one port; the control and analysis module drives the switch corresponding to any port to close during the timing switching cycle, and simultaneously drives the switching module to output electrical energy of the corresponding voltage and frequency to the port or to receive electrical energy output from the port; the DC bus capacitor is used in the energy system; the energy system supplies power to the loads connected to each port through the DC bus capacitor and the switching module or receives electrical energy output from the power supply connected to each port through the switching module and the DC bus capacitor.

[0006] In the above technical solution, the control analysis module calculates the corresponding voltage amplitude, frequency, and output power of the load or power supply connected to each port based on the voltage, current, and frequency of the load or power supply connected to each port, and determines the power supply cycle and timing required for the normal operation of the load connected to each port, thereby determining the control parameters of the drive signal of the switch module and the switch.

[0007] The above technical solution includes the following steps: After the energy system is turned on, the control and analysis module sorts and divides the switching cycles of the switching module according to the power characteristics of the loads or power supplies connected to the n ports, and determines the corresponding dead time for each switching cycle: In the i-th switching cycle, the switch of the i-th port is closed, and the switches of all other ports are open. The control and analysis module drives the switching module to work. If the i-th port is connected to a load, the power in the DC bus capacitor is output to the i-th port through the switching module based on the power characteristics of the load. If the i-th port is connected to a load, the power in the DC bus capacitor is output to the i-th port through the switching module. If the i ports are connected to a power source, the power output from that power source is sent to the DC bus capacitor via the switching module based on the power source's energy characteristics. At the end of the i-th switching cycle, the switch of the i-th port is turned off. During the dead time, the control analysis module turns off the switches of all ports and controls the switching module to stop working. After the dead time, the (i+1)-th switching cycle begins and the above process is repeated. After completing the input to the n-th port in the n-th switching cycle, it will return to the 1-th switching cycle to re-supply the load of the first port or receive the power output from the power source connected to that port.

[0008] In the above technical solution, the process by which the control and analysis module generates drive signals for the switching module and switches based on the power supply or load connected to each port includes: the control module acquiring the input voltage of the load connected to each port or the output voltage of the power supply connected to each port, and calculating the duty cycle of each port based on the DC bus capacitor voltage; and determining the switching period T of each port based on the following formula. i , i=1,2,...,n; V i =D i V DC (1) (2) D i T < T i (3) Among them, V DC V represents the DC bus capacitor voltage; i D represents the input voltage of the load connected to the i-th port or the output voltage of the power supply connected to it; i T represents the input voltage of the load connected to the i-th port or the duty cycle of the power supply connected to it; i The input voltage of the load connected to the i-th port or the duty cycle of the connected power supply is represented by f; f and T represent the operating frequency and period of the switching module, respectively. The beneficial effects of this invention are as follows: By reusing the same control module, this invention can simultaneously meet the efficient operation requirements of different types and categories of production equipment, thus eliminating the need for independent power supplies of different electrical systems. By connecting the switching module to different input and output ports and using a linear bus capacitor for charging and discharging, the number and types of power supplies required are reduced, further compressing the device size, simplifying the power supply scheme, and contributing to the stable operation of the entire system. Simultaneously, the flexible and effective AC / DC multiplexing function achieved through digital control can greatly improve energy conversion efficiency and enhance the overall performance of the energy router and even the energy internet.

[0009] Furthermore, the control and analysis module of the present invention determines the timing cycle based on the load and power supply connected to each port, ensuring that the devices connected to multiple ports can be used normally at the same time, thereby improving the overall utilization rate of the energy system.

[0010] Furthermore, the drive signal of the switching module of the present invention is divided into multiple timing switching cycles according to the number of ports, and the timing and dead time corresponding to each port are set to ensure the overall safety and stability of the energy system.

[0011] Furthermore, the control and analysis module of the present invention reasonably calculates the timing and switching cycle of each port based on the power characteristics of each port, ensuring that the devices connected to each port can be used normally. Attached Figure Description

[0012] Figure 1 This is a structural diagram of a power converter that provides AC / DC multiplexing and time-sequential output of different forms of electrical energy according to an embodiment of this application.

[0013] Figure 2 Figure a shows the control signals for a power converter that provides AC / DC multiplexing and time-sequential output of different forms of electrical energy in an embodiment of this application.

[0014] Figure 3 Figure b shows the control signals of a power converter that provides AC / DC multiplexing and time-sequential output of different forms of electrical energy in an embodiment of this application.

[0015] Figure 4 The flowchart of the AC / DC multiplexed power converter that outputs different forms of electrical energy in a time-sequence manner is provided in the embodiments of this application. Detailed Implementation

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments to facilitate a clear understanding of the present invention, but these descriptions do not constitute a limitation on the present invention.

[0017] like Figure 1 As shown, this invention provides an AC / DC multiplexed power converter: including a switching module, several ports, a DC bus capacitor, and a control and analysis module; each port is equipped with a switch; one end of the switching module is connected to the DC bus capacitor, and the other end is connected to the switch of each port; one end of each port is connected to a power source or load, and the other end is connected to the switch of that port; when the switch configured for any port is closed, the switches of other ports are open; one side of the DC bus capacitor is grounded, and the other side is connected to the switching module for energy exchange; the control and analysis module is connected to the switches and switching modules of each port through control lines, and is based on the power source connected to each port. Alternatively, the load generates drive signals for the switching module and the switch; the drive signals of the switching module are divided into multiple timing switching cycles according to the number of ports, with each timing switching cycle corresponding to one port; the control and analysis module drives the switch corresponding to any port to close during the timing switching cycle, and simultaneously drives the switching module to output electrical energy of the corresponding voltage and frequency to the port or to receive electrical energy output from the port; the DC bus capacitor is used in the energy system; the energy system supplies power to the loads connected to each port through the DC bus capacitor and the switching module or receives electrical energy output from the power supply connected to each port through the switching module and the DC bus capacitor.

[0018] In the above technical solution, the control analysis module calculates the corresponding voltage amplitude, frequency, and output power of the load or power supply connected to each port based on the voltage, current, and frequency of the load or power supply connected to each port, and determines the power supply cycle and timing required for the normal operation of the load connected to each port, thereby determining the control parameters of the drive signal of the switch module and the switch.

[0019] The above technical solution includes the following steps: After the energy system is turned on, the control and analysis module sorts and divides the switching cycles of the switching module according to the power characteristics of the loads or power supplies connected to the n ports, and determines the corresponding dead time for each switching cycle: In the i-th switching cycle, the switch of the i-th port is closed, and the switches of all other ports are open. The control and analysis module drives the switching module to work. If the i-th port is connected to a load, the power in the DC bus capacitor is output to the i-th port through the switching module based on the power characteristics of the load. If the i-th port is connected to a load, the power in the DC bus capacitor is output to the i-th port through the switching module. If the i ports are connected to a power source, the power output from that power source is sent to the DC bus capacitor via the switching module based on the power source's energy characteristics. At the end of the i-th switching cycle, the switch of the i-th port is turned off. During the dead time, the control analysis module turns off the switches of all ports and controls the switching module to stop working. After the dead time, the (i+1)-th switching cycle begins and the above process is repeated. After completing the input to the n-th port in the n-th switching cycle, it will return to the 1-th switching cycle to re-supply the load of the first port or receive the power output from the power source connected to that port.

[0020] The DC bus capacitor can be a regular capacitor in principle, or a supercapacitor with a larger energy storage capacity, faster charging and discharging speed, and longer cycle life can be selected according to the actual situation.

[0021] Pulse width modulation is based on the principle of area equivalence, that is, when narrow pulses with equal impulse but different shapes are applied to a component with inertia, their effects are basically the same, thus proving the feasibility of AC-DC conversion based on PWM.

[0022] Based on the PWM principle, the AC / DC multiplexing port device can simultaneously realize the functions of chopping, rectification and inversion of traditional circuits in a digital manner by controlling the charging and discharging timing of the switching devices (IGBT, MOSFET, etc.) modules in the port.

[0023] This invention provides a power converter that multiplexes AC and DC power and outputs different forms of electrical energy in a time-sequential manner. When multiple forms of electrical energy are required, a control and analysis module controls a switching module, dividing its switching drive signal into multiple time-sequential switching cycles according to the number of output ports. Each time-sequential switching cycle corresponds to a separate port, thereby achieving the output of multiple channels of electrical energy with different voltages and frequencies from a single switching module. This not only provides different electrical systems to each port simultaneously, but also reduces the number and types of power supplies required by the system, compresses the device size, simplifies the power supply scheme, improves system stability, reduces unnecessary system losses caused by multiple power supplies, improves energy conversion efficiency, and enhances the overall performance of energy routers and even the energy internet.

[0024] The output voltage of the n ports and the DC bus voltage involved in this invention are determined by their duty cycles: V i =D i V DC (1) The duty cycle is related to the operating frequency f of the switching module. The switching cycle of each port is slightly larger than its duty cycle to ensure that there is a dead time between adjacent switching cycles so that they will not affect each other.

[0025] (2) D i T < T i (3) Among them, V DC V represents the DC bus capacitor voltage; i D represents the input voltage of the load connected to the i-th port or the output voltage of the power supply connected to it; i T represents the input voltage of the load connected to the i-th port or the duty cycle of the power supply connected to it; i The input voltage of the load connected to the i-th port or the operating cycle of the power supply connected to it is indicated; f and T represent the operating frequency and cycle of the switching module, respectively.

[0026] In one embodiment, a power converter that multiplexes AC and DC power and outputs different forms of electrical energy in a time-sequential manner includes some or all of the following technical features: In one embodiment, an AC / DC multiplexed simultaneous power supply port device has a bus voltage set to V. DC =800VDC, consisting of three main operating modes: DC voltage output from port 1 V1=100VDC, AC voltage output from port 2 V2=220VAC, and AC voltage output from port 3 V3=110VAC.

[0027] Since the maximum value of AC voltage is the effective value multiplied by ,but , According to formula (1), D1=0.125; D2=0.39; D3=0.2 can be calculated; then T1=0.2; T2=0.5; T3=0.3 are set.

[0028] like Figure 2 and Figure 3 As shown, each working mode is divided into several operations.

[0029] In the DC voltage output mode of port 1, during the first and (n+1)th switching cycles, the switch of port 1 is closed, and the switches of port 2 and port 3 are open. The control analysis module controls the switching module to output 100VDC.

[0030] In the AC voltage output mode of port 2, during the 2nd and n+2nd switching cycles, the switch of port 2 is closed, and the switches of port 1 and port 3 are open. The control analysis module controls the switch module to output the AC voltage required by port 2 with a peak value of 311V.

[0031] In the AC voltage output mode of port 3, during the 3rd and (n+3rd)th switching cycles, the switch of port 3 is closed, and the switches of port 1 and port 2 are open. The control analysis module controls the switch module to output the AC voltage required by port 3 with a peak value of 155V.

[0032] In one embodiment, the AC / DC multiplexed power supply port device includes: a switching module, several output ports, a port switch configured for each port, a DC bus capacitor, and a control and analysis module.

[0033] The switching module is used to output electrical energy at various voltages and frequencies, including DC and AC. The port switch configured on each port will close when the switching module outputs power. The DC bus capacitor is generally used as a power source, but in some scenarios, supercapacitors or batteries can also be used.

[0034] The control and analysis module is connected to each port switch and switch module via control lines. It receives data such as voltage, current, and frequency detected by the system and further obtains data such as power and current direction. It analyzes the state of the equipment and then controls the switch module to enter the corresponding working mode and adjust the control parameters according to the analysis results.

[0035] The control and analysis module is connected to the switching module, DC bus capacitor, port switches, and other devices via control lines. It receives voltage, current, and frequency data detected by the energy system and further obtains data such as power and harmonic status. It analyzes the state of the switching module and then controls it to enter the corresponding operating mode based on the analysis results. This module includes a power supply unit, communication lines, a control chip, and an external interaction port. The power supply unit provides power to the module; the control chip processes the voltage and current signals detected by the system, stores the data, and generates control signals; the communication lines serve as the signal transmission channel; and the external interaction port allows the control and analysis module to exchange information with external systems.

[0036] like Figure 1 As shown in the diagram, a power converter that multiplexes AC and DC power and outputs different forms of electrical energy in a time-division manner operates according to the following steps: like Figure 4 As shown, after the energy system is turned on, the control and analysis module divides the switching cycle into three parts based on the different electrical characteristics such as the required voltage and frequency of the three ports. During switching cycle 1, the control and analysis module controls port 1 to close and outputs the required DC voltage. Then, during the dead time, the control and analysis module disconnects all port switches, and the switching module stops working. Next, during switching cycle 2, the control and analysis module controls port 2 to close and outputs the required AC voltage. During the subsequent dead time, it disconnects all port switches, and the switching module stops working. Then, during switching cycle 3, the control and analysis module controls port 3 to close and outputs the required AC voltage. During the subsequent dead time, it disconnects all port switches, and the switching module stops working. After the dead time ends, the workflow in switching cycle 1 is repeated.

[0037] If configured using a standard power supply, one set of 800VDC-100VDC (port 1) converter, one set of 800VDC-220VAC (port 2) inverter, and one set of 800VDC-110VAC (port 3) inverter are required. If each inverter and converter uses a full-bridge circuit with four switching elements, then a total of 3... 4 = 12 switching elements, and each inverter and converter needs to be equipped with a corresponding control chip and drive circuit.

[0038] In this embodiment, the three output ports can be effectively reused by the same set of switching modules to simultaneously complete the output of 800VDC-100VDC (port 1), 800VDC-220VAC (port 2), and 800VDC-110VAC (port 3). Only one full-bridge circuit, i.e., four switching elements, is required. However, with the addition of port switches 1, 2, and 3, a total of six switching devices are needed, for a total of 4+6=10 switching elements. This effectively saves two switching elements and their corresponding control chips and drive circuits.

[0039] Similarly, if a 4-port output is used, 4 ports can be saved. 4-(4+2) 4) Cost of 4 switching elements. Therefore, compared with the prior art, this invention can not only effectively improve energy conversion efficiency but also further save equipment costs, thereby improving the overall economic benefits of the energy system.

[0040] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

Claims

1. An AC / DC multiplexed power converter, characterized in that: It includes a switch module, several ports, a DC bus capacitor, and a control and analysis module; each port is equipped with a switch; one end of the switch module is connected to the DC bus capacitor, and the other end is connected to the switch of each port; one end of each port is connected to a power supply or load, and the other end is connected to the switch of that port. When the switch configured on any port is closed, the other switches are open; one side of the DC bus capacitor is grounded, and the other side is connected to the switch module for energy exchange; the control and analysis module connects to the switches and switch modules of each port through control lines, and generates drive signals for the switch modules and switches based on the power supply or load connected to each port; the drive signals of the switch modules are divided into multiple timing switch cycles according to the number of ports, and each timing switch cycle corresponds to one port; in the timing switch cycle corresponding to any port, the control and analysis module drives the switch corresponding to that port to close, and at the same time drives the switch module to output electrical energy of the corresponding voltage and frequency to that port or receive electrical energy output from that port; the DC bus capacitor is used in the energy system; The energy system supplies power to the loads connected to each port through the DC bus capacitor and the switching module, or receives electrical energy from the power supply connected to each port through the switching module and the DC bus capacitor. After the energy system is turned on, the control and analysis module sorts and divides the switching cycles of the switching module according to the power characteristics of the loads or power supplies connected to the n ports, and determines the corresponding dead time for each switching cycle: During the i-th switching cycle, the switch of the i-th port is closed, and the switches of all other ports are open. The control and analysis module drives the switching module to work. If the i-th port is connected to a load, the power in the DC bus capacitor is output to the i-th port through the switching module based on the power characteristics of the load. If the i-th port is connected to a power supply, the power output by the power supply is output to the DC bus capacitor through the switching module based on the power characteristics of the power supply. At the end of the i-th switching cycle, the switch of the i-th port is opened. During the dead time, the control and analysis module opens the switches of all ports and controls the switching module to stop working. After the dead time, the (i+1)-th switching cycle begins and the above process is repeated. After completing the input to the n-th port in the n-th switching cycle, it will return to the 1-th switching cycle and re-supply the load of the first port or receive the power output from the power supply connected to that port.

2. The AC / DC multiplexed power converter according to claim 1, characterized in that: The control analysis module calculates the corresponding voltage amplitude, frequency, and output power of the load or power supply connected to each port based on the voltage, current, and frequency of the load or power supply connected to each port, and determines the power supply cycle and timing required for the normal operation of the load connected to each port, thereby determining the control parameters of the switch module and the drive signal of the switch.

3. A power converter for AC / DC multiplexing according to claim 1, characterized in that: The process by which the control analysis module generates drive signals for the switching module and switches based on the power supply or load connected to each port includes: the control module acquiring the input voltage of the load connected to each port or the output voltage of the power supply connected to each port, and calculating the duty cycle of each port based on the DC bus capacitor voltage; and determining the switching period T of each port based on the following formula. i , i=1,2,...,n; （1） （2） （3） Among them, V DC V represents the DC bus capacitor voltage; i D represents the input voltage of the load connected to the i-th port or the output voltage of the power supply connected to it; i T represents the input voltage of the load connected to the i-th port or the duty cycle of the power supply connected to it; i The input voltage of the load connected to the i-th port or the operating cycle of the power supply connected to it is indicated; f and T represent the operating frequency and cycle of the switching module, respectively.

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