CN116436278A - AC/DC multiplexing power converter and control method thereof - Google Patents

Abstract

The technical scheme adopted by the invention is as follows: an AC/DC multiplexing power converter and a control method thereof are provided: the device comprises a switch module, a plurality of ports, a direct current bus capacitor and a control analysis module; each path of port is provided with a switch; one end of the switch module is connected with the direct current bus capacitor, and the other end of the switch module is connected with a switch of each path of port; one end of the port is connected with a power supply or a load, and the other end of the port is connected with a switch of the port; when the switch configured by any one path of port is closed, the other paths of switches are opened; one side of the direct current bus capacitor is grounded, and the other side of the direct current bus capacitor is connected with the switch module to exchange energy; the control analysis module is connected with the switch of each port and the switch module through control lines, and generates driving signals of the switch module and the switch based on power supplies or loads connected with each port. The invention can output electric energy in different forms in time sequence.

Description

AC/DC multiplexing power converter and control method thereof

Technical Field

The invention belongs to the technical field of electricity, and particularly relates to an alternating current-direct current multiplexing power converter and a control method thereof.

Background

The energy internet can be understood as a novel power network node formed by a large number of distributed energy acquisition devices, distributed energy storage devices and various loads, which is formed by comprehensively applying advanced power electronic technology, information technology and intelligent management technology, so as to realize energy peer-to-peer exchange and sharing network of energy bidirectional flow.

Various types of energy devices need to perform energy conversion when accessing the energy internet. When a conventional controller processes access of various types of energy devices, effective conversion of energy needs to be achieved through complicated ac-dc analog conversion devices or transformers for different types of energy devices, and each conversion needs different devices, such as dc-dc conversion and dc-ac conversion, wherein the voltage, frequency and phase of ac may be different. In order to meet the requirements of different electric equipment, the conversion system is provided with more power supplies, so that the device is large in size, the power supply scheme is complex, the system loss is increased, and the stable operation of the whole system is not facilitated.

Disclosure of Invention

The invention aims to solve the defects in the background technology and provide an AC/DC multiplexing power converter and a control method thereof, which can output electric energy in different forms in a time-sharing way.

The technical scheme adopted by the invention is as follows: an AC/DC multiplexing power converter: the device comprises a switch module, a plurality of ports, a direct current bus capacitor and a control analysis module; each path of port is provided with a switch; one end of the switch module is connected with the direct current bus capacitor, and the other end of the switch module is connected with a switch of each path of port; one end of the port is connected with a power supply or a load, and the other end of the port is connected with a switch of the port; when the switch configured by any one path of port is closed, the other paths of switches are opened; one side of the direct current bus capacitor is grounded, and the other side of the direct current bus capacitor is connected with the switch module to exchange energy; the control analysis module is connected with the switch and the switch module of each port through control lines and generates driving signals of the switch module and the switch based on power supplies or loads connected with each port; the driving signals of the switch module are divided into a plurality of time sequence switch periods according to the number of ports, and each time sequence switch period corresponds to one port respectively; the control analysis module drives the switch corresponding to any port to be closed in a time sequence switching period corresponding to the port, and simultaneously drives the switch module to output electric energy with corresponding voltage and frequency to the port or receive electric energy output by the port; the direct current bus capacitor is applied to an energy system; the energy system supplies power to loads connected with the ports through the direct current bus capacitors and the switch modules or receives electric energy output by a power supply connected with the ports through the switch modules and the direct current bus capacitors.

According to the technical scheme, the control analysis module calculates the voltage, the current and the frequency of the load or the power supply connected with each port to obtain the corresponding voltage amplitude, the frequency and the output power of each port according to the voltage, the current and the frequency of the load or the power supply connected with each port, and determines the power supply period and the time sequence required by the normal operation of the load connected with each port, so as to determine the control parameters of the switch module and the driving signals of the switch.

The technical scheme comprises the following steps: after the energy system is started, the control analysis module orders and divides the switching period of the switching module according to the number of the n ports and the electric energy characteristics of the power supply, and determines the corresponding dead time of each switching period, wherein the switch of the ith port is closed in the ith switching period, the switches of all other ports are opened, the control analysis module drives the switching module to work, if the ith port is connected with the load, the electric energy in the direct current bus capacitor is output to the ith port through the switching module based on the electric energy characteristics of the load, and if the ith port is connected with the power supply, the electric energy output by the power supply is output to the direct current bus capacitor through the switching module based on the electric energy characteristics of the power supply; when the ith switching period is finished, the switch of the ith port is disconnected; in the dead time, controlling the analysis module to disconnect the switches of all ports and controlling the switch module to stop working; after the dead time, the (i+1) th switching period starts and the process is repeated; after the input of the nth switching period to the nth port is completed, the 1 st switching period is returned to, and the load of the first port is supplied with power again or the electric energy output by the power supply connected with the port is received.

In the above technical solution, the process of generating the driving signals of the switch module and the switch by the control analysis module based on the power source or the load connected to each port includes: the control module obtains the input voltage of a connected load or the output voltage of a connected power supply of each port, and calculates the duty ratio of each port based on the DC bus capacitor voltage; determining the switching period T of each port based on _i ，i＝1,2,...,n；

V _i ＝D _i *V _DC (1)

D _i ＜T _i (3)

Wherein V is _DC Representing the voltage of a direct current bus capacitor; v (V) _i Representing the input voltage of the connected load of the i-th port or the output voltage of the connected power supply; d (D) _i Representing the input voltage of the connected load of the i-th port or the duty cycle of the connected power supply; t (T) _i The input voltage of the connected load of the i-th port or the duty cycle of the connected power supply; f and T respectively represent the operating frequency and period of the switch module

The beneficial effects of the invention are as follows: the invention can meet the requirements of high-efficiency operation of different types and different kinds of production equipment by multiplexing the same control module, and is not restricted by independent power supply of electric energy of different electric systems. The switch modules are connected through different input and output ports, and the linear bus capacitors are used for realizing charge and discharge, so that the number and types of the matched power supplies are reduced, the device volume is further reduced, the power supply scheme is simplified, and the stable operation of the whole system is facilitated. Meanwhile, the flexible and effective AC/DC multiplexing function is realized through digital control, so that the energy conversion efficiency can be greatly improved, and the overall performance of the energy router and even the energy Internet can be improved.

Furthermore, the control analysis module determines the time sequence period based on the load and the power supply connected with each port, so that the equipment connected with a plurality of ports can be used normally at the same time, and the overall utilization rate of the energy system is improved.

Furthermore, the driving signal of the switch module is divided into a plurality of time sequence switch periods according to the number of ports, and the time sequence and dead time corresponding to each port are set, so that the overall safety and stability of the energy system are ensured.

Furthermore, the control analysis module reasonably calculates the time sequence and the switching period of each port based on the electric energy characteristics of each port, and ensures that the equipment connected with each port can be normally used.

Drawings

Fig. 1 is a block diagram of a power converter for outputting different forms of electric energy in a time-sharing sequence by ac/dc multiplexing according to an embodiment of the present application.

Fig. 2 is a control signal diagram a of a power converter for outputting different forms of electric energy in a time-sharing manner by ac/dc multiplexing according to an embodiment of the present application.

Fig. 3 is a control signal diagram b of a power converter for outputting different forms of electric energy in a time-sharing manner by ac/dc multiplexing according to an embodiment of the present application.

Fig. 4 is a flowchart of an ac/dc multiplexed time-division power converter for outputting different forms of power according to an embodiment of the present application.

Detailed Description

The invention will now be described in further detail with reference to the drawings and specific examples, which are given for clarity of understanding and are not to be construed as limiting the invention.

As shown in fig. 1, the present invention provides an ac-dc multiplexed power converter: the device comprises a switch module, a plurality of ports, a direct current bus capacitor and a control analysis module; each path of port is provided with a switch; one end of the switch module is connected with the direct current bus capacitor, and the other end of the switch module is connected with a switch of each path of port; one end of the port is connected with a power supply or a load, and the other end of the port is connected with a switch of the port; when the switch configured by any one path of port is closed, the other paths of switches are opened; one side of the direct current bus capacitor is grounded, and the other side of the direct current bus capacitor is connected with the switch module to exchange energy; the control analysis module is connected with the switch and the switch module of each port through control lines and generates driving signals of the switch module and the switch based on power supplies or loads connected with each port; the driving signals of the switch module are divided into a plurality of time sequence switch periods according to the number of ports, and each time sequence switch period corresponds to one port respectively; the control analysis module drives the switch corresponding to any port to be closed in a time sequence switching period corresponding to the port, and simultaneously drives the switch module to output electric energy with corresponding voltage and frequency to the port or receive electric energy output by the port; the direct current bus capacitor is applied to an energy system; the energy system supplies power to loads connected with the ports through the direct current bus capacitors and the switch modules or receives electric energy output by a power supply connected with the ports through the switch modules and the direct current bus capacitors.

According to the technical scheme, the control analysis module calculates the voltage, the current and the frequency of the load or the power supply connected with each port to obtain the corresponding voltage amplitude, the frequency and the output power of each port according to the voltage, the current and the frequency of the load or the power supply connected with each port, and determines the power supply period and the time sequence required by the normal operation of the load connected with each port, so as to determine the control parameters of the switch module and the driving signals of the switch.

The technical scheme comprises the following steps: after the energy system is started, the control analysis module orders and divides the switching period of the switching module according to the number of the n ports and the electric energy characteristics of the power supply, and determines the corresponding dead time of each switching period, wherein the switch of the ith port is closed in the ith switching period, the switches of all other ports are opened, the control analysis module drives the switching module to work, if the ith port is connected with the load, the electric energy in the direct current bus capacitor is output to the ith port through the switching module based on the electric energy characteristics of the load, and if the ith port is connected with the power supply, the electric energy output by the power supply is output to the direct current bus capacitor through the switching module based on the electric energy characteristics of the power supply; when the ith switching period is finished, the switch of the ith port is disconnected; in the dead time, controlling the analysis module to disconnect the switches of all ports and controlling the switch module to stop working; after the dead time, the (i+1) th switching period starts and the process is repeated; after the input of the nth switching period to the nth port is completed, the 1 st switching period is returned to, and the load of the first port is supplied with power again or the electric energy output by the power supply connected with the port is received.

The direct current bus capacitor can be a common capacitor in principle, and can be a super capacitor with larger electricity storage capacity, faster charge and discharge speed and longer cycle life according to actual conditions.

The pulse width modulation is based on the area equivalent principle, namely that when narrow pulses with equal impulses and different shapes are added to links with inertia, the effect is basically the same, thereby proving the feasibility of carrying out AC-DC conversion based on PWM.

Based on the PWM principle, the AC/DC multiplexing port equipment can realize the functions of chopping, rectifying, inverting and the like of the traditional circuit in a digital mode through controlling the charge and discharge time sequence of a switch device (IGBT, MOSFET and the like) module in the port.

The invention provides a power converter for outputting electric energy in different forms in a time-sharing mode by AC/DC multiplexing. Under the condition that multiple forms of electric energy are needed, the control analysis module is used for controlling the switch module, the switch driving signal is divided into multiple time sequence switch periods according to the number of output ports, and each time sequence switch period corresponds to an independent port, so that the purpose of outputting multiple paths of electric energy with different voltages and frequencies by the same switch module is achieved. The system not only can provide electric energy with different systems for each port, but also reduces the quantity and types of power sources originally required to be provided by the system, compresses the volume of the device, simplifies the power supply scheme, improves the system stability, reduces unnecessary system loss caused by a plurality of power sources, improves the energy conversion efficiency, and improves the overall performance of the energy router and even the energy Internet.

The output voltage of n ports and the bus direct current voltage related to the invention are determined by the duty ratio:

V _i ＝D _i *V _DC (1)

the duty cycle is related to the working frequency f of the switch module, and the switch period of each port is slightly larger than the duty cycle of each port so as to ensure that dead time exists in the adjacent switch periods, so that the adjacent switch periods cannot be mutually influenced.

D _i ＜T _i (3)

Wherein V is _DC Representing the voltage of a direct current bus capacitor; v (V) _i Representing the input voltage of the connected load of the i-th port or the output voltage of the connected power supply; d (D) _i Representing the input voltage of the connected load of the i-th port or the duty cycle of the connected power supply; t (T) _i The input voltage of the connected load of the i-th port or the duty cycle of the connected power supply; f and T represent the operating frequency and period of the switching module, respectively.

In one embodiment, a power converter for outputting different forms of electric energy in a time-sharing manner by ac/dc multiplexing includes some or all of the following technical features:

in one embodiment, an ac/dc multiplexing simultaneous power supply port device, the bus voltage is set to V _DC =800 VDC, output dc voltage V from port 1 ₁ =100 VDC, port 2 output ac voltage V ₂ =220 VAC, port 3 output ac voltage V ₃ =110 VAC three main operating mode procedures.

Since the maximum value of the alternating voltage is the effective value multiplied by

Then

From the formula (1), D can be calculated ₁ ＝0.125；D ₂ ＝0.39；D ₃ =0.2; thereafter set T ₁ ＝0.2；T ₂ ＝0.5；T ₃ ＝0.3。

As shown in fig. 2 and 3, each operating mode is divided into several operations.

In the direct-current voltage mode output by the port 1, in the 1 st and n+1st switching periods, the switch of the port 1 is closed, the switch of the port 2 and the switch of the port 3 are opened, and the control analysis module controls the switch module to output 100VDC.

In the mode of outputting alternating voltage by the port 2, in the 2 nd and n+2th switching periods, the switch of the port 2 is closed, the switches of the port 1 and the port 3 are opened, and the control analysis module controls the switching module to output alternating voltage with the peak value of 311V required by the port 2.

In the mode of outputting alternating voltage by the port 3, in the 3 rd and n+3 th switching periods, the switch of the port 3 is closed, the switches of the port 1 and the port 2 are opened, and the control analysis module controls the switching module to output the alternating voltage with the peak value of 155V required by the port 3.

In one embodiment, the structure of the ac-dc multiplexed simultaneous power supply port device includes: the system comprises a switch module, a plurality of output ports, port switches configured for each port, a direct current bus capacitor and a control analysis module.

The switch module is used for outputting electric energy with various voltages and various frequencies including direct current and alternating current. The port switch configured by each port is closed when the switch module outputs power to the port switch, the direct current bus capacitor is generally used as a power supply, and a super capacitor or a storage battery can be used in certain occasions.

The control analysis module is connected with each port switch and the switch module through a control line, receives data such as voltage, current, frequency and the like detected by the system, further obtains data such as power, current direction and the like, analyzes the state of equipment, and further controls the switch module to enter a corresponding working mode according to an analysis result, and adjusts control parameters.

The control analysis module is connected with devices such as a switch module, a direct current bus capacitor, a port switch and the like through control lines, and is responsible for receiving data such as voltage, current, frequency and the like detected by an energy system and further obtaining data such as power, harmonic conditions and the like, analyzing the state of the switch module, and further controlling the switch module to enter a corresponding working mode according to analysis results. The module comprises a power supply unit, a communication line, a control chip and an external interaction port. The power supply unit is responsible for supplying power to the module; the control chip is used for carrying out data processing on the voltage and current signals detected by the system, storing data and generating control signals; the communication line is used as a channel for signal transmission; the external interaction port is used for controlling the analysis module to interact information with the outside.

As shown in the structure of fig. 1, a power converter for outputting electric energy in different forms in a time-sharing sequence by using ac-dc multiplexing is operated according to the following steps:

as shown in fig. 4, after the energy system is turned on, the control analysis module divides the switching period into 3 parts according to the number of ports according to different electric energy characteristics such as voltage and frequency required by the three ports. Then, in the switching period 1, the control analysis module controls the port 1 to be switched on and switched off, and outputs the direct current voltage required by the port 1. And then, in the dead time, the control analysis module turns off all the port switches, and the switch module stops working. And then, the control analysis module controls the port 2 switch to be closed in the switching period 2, outputs the alternating voltage required by the port 2, and opens all the port switches in the subsequent dead time, so that the switching module stops working. Then, the control analysis module controls the port 3 switch to be closed in the switching period 3, outputs the alternating voltage required by the port 3, and opens all the port switches in the following dead time, so that the switching module stops working. After the dead time is over, the workflow in switching cycle 1 is repeated.

If the power supply is configured according to a conventional power supply, a set of 800VDC-100VDC (port 1) converters 1, a set of 800VDC-220VAC (port 2) converters 1 and a set of 800VDC-110VAC (port 3) converters 1 are needed, if each set of converters and converters adopts a full bridge circuit with 4 switching elements, 3×4=12 switching elements are needed, and each set of converters and converters is provided with a corresponding control chip and a driving circuit.

In this embodiment, the 3 output ports can be effectively multiplexed into 1 set of switch modules, and simultaneously output 800VDC-100VDC (port 1), 800VDC-220VAC (port 2) and 800VDC-110VAC (port 3) is completed, and only one set of full bridge circuit, namely 4 switch elements, is needed, but the port switches 1, 2 and 3 are added to 6 switch elements, and 4+6=10 switch elements are added, so that 2 switch elements and control chips and driving circuits matched with the switch elements are effectively saved.

Similarly, if a 4-port output is used, the cost of 4*4- (4+2×4) =4 switching elements can be saved. Compared with the prior art, the invention not only can effectively improve the energy conversion efficiency, but also can further save the equipment cost, thereby improving the overall economic benefit of the energy system.

What is not described in detail in this specification is prior art known to those skilled in the art.

Claims (4)

1. An ac-dc multiplexed power converter, characterized by: the device comprises a switch module, a plurality of ports, a direct current bus capacitor and a control analysis module; each path of port is provided with a switch; one end of the switch module is connected with the direct current bus capacitor, and the other end of the switch module is connected with a switch of each path of port; one end of the port is connected with a power supply or a load, and the other end of the port is connected with a switch of the port; when the switch configured by any one path of port is closed, the other paths of switches are opened; one side of the direct current bus capacitor is grounded, and the other side of the direct current bus capacitor is connected with the switch module to exchange energy; the control analysis module is connected with the switch and the switch module of each port through control lines and generates driving signals of the switch module and the switch based on power supplies or loads connected with each port; the driving signals of the switch module are divided into a plurality of time sequence switch periods according to the number of ports, and each time sequence switch period corresponds to one port respectively; the control analysis module drives the switch corresponding to any port to be closed in a time sequence switching period corresponding to the port, and simultaneously drives the switch module to output electric energy with corresponding voltage and frequency to the port or receive electric energy output by the port; the direct current bus capacitor is applied to an energy system; the energy system supplies power to loads connected with the ports through the direct current bus capacitors and the switch modules or receives electric energy output by a power supply connected with the ports through the switch modules and the direct current bus capacitors.

2. An ac/dc multiplexed power converter as claimed in claim 1, wherein: the control analysis module calculates the load or the power supply connected with each port according to the voltage, the current and the frequency of the load or the power supply connected with each port to obtain the corresponding voltage amplitude, the frequency and the output power of each port, and determines the power supply period and the time sequence required by the normal operation of the load connected with each port, thereby determining the control parameters of the switch module and the driving signals of the switch.

3. The control method of the power converter based on the alternating current-direct current multiplexing as claimed in claim 1, wherein the control method comprises the following steps: the method comprises the following steps: after the energy system is started, the control analysis module orders and divides the switching period of the switching module according to the number of the n ports and the electric energy characteristics of the power supply, and determines the corresponding dead time of each switching period, wherein the switch of the ith port is closed in the ith switching period, the switches of all other ports are opened, the control analysis module drives the switching module to work, if the ith port is connected with the load, the electric energy in the direct current bus capacitor is output to the ith port through the switching module based on the electric energy characteristics of the load, and if the ith port is connected with the power supply, the electric energy output by the power supply is output to the direct current bus capacitor through the switching module based on the electric energy characteristics of the power supply; when the ith switching period is finished, the switch of the ith port is disconnected; in the dead time, controlling the analysis module to disconnect the switches of all ports and controlling the switch module to stop working; after the dead time, the (i+1) th switching period starts and the process is repeated; after the input of the nth switching period to the nth port is completed, the 1 st switching period is returned to, and the load of the first port is supplied with power again or the electric energy output by the power supply connected with the port is received.

4. A method according to claim 3, characterized in that: the process of the control analysis module generating the switch module and the driving signal of the switch based on the power source or the load connected to each port includes: the control module obtains the connection negative of each portThe load input voltage or the output voltage of a connected power supply, and the duty ratio of each port is calculated based on the DC bus capacitor voltage; determining the switching period T of each port based on _i ，i＝1,2,...,n；

V _i ＝D _i *V _DC (1)

D _i ＜T _i (3)

Wherein V is _DC Representing the voltage of a direct current bus capacitor; v (V) _i Representing the input voltage of the connected load of the i-th port or the output voltage of the connected power supply; d (D) _i Representing the input voltage of the connected load of the i-th port or the duty cycle of the connected power supply; t (T) _i The input voltage of the connected load of the i-th port or the duty cycle of the connected power supply; f and T represent the operating frequency and period of the switching module, respectively.

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