A variable structure photovoltaic electric vehicle charging pile

Abstract

The present invention provides a variable structure photovoltaic electric vehicle charging pile, including: photovoltaic, main circuit, control circuit and topology selection circuit; the main circuit is used to convert the photovoltaic output into a controllable output under the control of the control circuit to power the load; the main circuit is provided with two conversion topologies with different voltage gain ranges; the topology selection circuit obtains the output after the main circuit conversion, and compares the current output value with the reference value, and selects the conversion topology corresponding to the voltage gain range according to the size relationship between the two. The charging pile of the present invention has two working topologies and a wide voltage range. At the same time, different topological structures are selected to meet the load requirements when the load and input change, which has strong adaptability.

Description

Technical Field

[0001] The present invention belongs to the technical field of charging piles, and in particular relates to a variable structure photovoltaic electric vehicle charging pile. Background Art

[0002] The topology of traditional power electronic converters is fixed, and the voltage gain is limited by the form of the topology. The voltage gain can be changed by adjusting parameters such as the duty cycle, and is applied to electric vehicle charging piles.

[0003] However, existing traditional power electronic converters still have the following problems: (1) The converter voltage gain is limited by the topology structure, which makes it difficult to meet the needs of high gain; (2) The circuit flexibility is low, which makes it difficult to meet the needs under complex working conditions; (3) The circuit makes it difficult to ensure the normal operation of the system in the event of a fault. Summary of the invention

[0004] In view of this, the present invention aims to propose a variable structure photovoltaic electric vehicle charging pile, which is used to at least solve the problem that the converter voltage gain of traditional power electronic converters is limited by the topological structure and is difficult to meet the occasions requiring high gain.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A variable structure photovoltaic electric vehicle charging pile, comprising: photovoltaic, main circuit, control circuit and topology selection circuit;

[0007] The main circuit is used to convert the photovoltaic output into a controllable output under the control of the control circuit so as to supply power to the load;

[0008] The main circuit is provided with two conversion topologies with different voltage gain ranges;

[0009] The topology selection circuit obtains the output after the main circuit transformation, compares the current output value with the reference value, and selects the transformation topology corresponding to the voltage gain range according to the size relationship between the two.

[0010] Further, the topology selection circuit includes: a group of relays and comparators;

[0011] The comparator is used to compare the transformed output of the main circuit with a reference value, and if the output is less than the reference value, a signal for switching to the first topology is generated; otherwise, a signal for switching to the second topology is generated;

[0012] A group of relays is connected to the main circuit, and is used to switch the conversion topology of the main circuit to the first conversion topology according to the switching first topology signal or to switch the conversion topology of the main circuit to the second conversion topology according to the switching second topology signal.

[0013] Further, the first conversion topology includes a first inductor, a second inductor, a first switch tube, and a second switch tube;

[0014] The first inductor serves as the first branch, one end of which is connected to the negative electrode of the first switch tube and then connected between the photovoltaic end and the load end, and the other end of which is connected to the negative electrode of the second switch tube and then connected between the photovoltaic end and the load end;

[0015] The second inductor serves as the second branch, one end of which is connected to the positive electrode of the first switch tube and then connected between the photovoltaic end and the load end, and the other end of which is connected to the positive electrode of the second switch tube and then connected between the photovoltaic end and the load end;

[0016] The first switch tube and the second switch tube are both controlled by a control circuit.

[0017] Furthermore, the voltage gain of the first conversion topology is as follows:

[0018]

[0019] Wherein, G1 is the voltage gain of the first conversion topology, and d is the duty cycle of the switch tube controlled by the control circuit.

[0020] Further, the second conversion topology includes a first coupled inductor, a second coupled inductor, a first switch tube, and a second switch tube;

[0021] The first coupled inductor serves as the first branch, one end of which is connected to the negative electrode of the first switch tube and then connected between the photovoltaic end and the load end, and the other end of which is connected to the negative electrode of the second switch tube and then connected between the photovoltaic end and the load end;

[0022] The second coupled inductor serves as the second branch, one end of which is connected to the positive electrode of the first switch tube and then connected between the photovoltaic end and the load end, and the other end of which is connected to the positive electrode of the second switch tube and then connected between the photovoltaic end and the load end;

[0023] The first switch tube and the second switch tube are both controlled by a control circuit.

[0024] Further, the first coupled inductor and the second coupled inductor each include two inductors and two diodes;

[0025] The same-name end of the first inductor of the two inductors is used as one end of the branch, and the opposite-name end is connected to the anodes of the two diodes respectively;

[0026] The same-name end of the second inductor of the two inductors is connected to the cathode of one of the two diodes, and the opposite-name end is connected to the cathode of the other diode to serve as the other end of the branch.

[0027] Furthermore, the voltage gain of the second conversion topology is as follows:

[0028]

[0029] Wherein, G2 is the voltage gain of the second conversion topology, d is the duty cycle of the switch tube controlled by the control circuit, and n is the turns ratio between the two inductors.

[0030] Furthermore, the number of relays in a group is set to 4, wherein the first branch of the first conversion topology is connected to the main circuit through a static contact of the first relay and a static contact of the third relay, the second branch is connected to the main circuit through a static contact of the second relay and a static contact of the fourth relay, the first branch of the second conversion topology is connected to the main circuit through another static contact of the first relay and another static contact of the third relay, and the second branch is connected to the main circuit through another static contact of the second relay and another static contact of the fourth relay.

[0031] Furthermore, the process of the topology selection circuit selecting the conversion topology corresponding to the voltage gain range specifically includes:

[0032] When the output of the main circuit after the conversion is less than the reference value, the comparator outputs a low-level signal, which is divided into four signals, two of which are directly used as control signals of the second relay and the fourth relay to control the second branch of the first conversion topology to connect to the main circuit, and the other two signals are passed through the NOT gate to obtain two high-level signals as control signals of the first relay and the third relay to control the first branch of the first conversion topology to connect to the main circuit;

[0033] When the output of the main circuit after transformation is compared and is not less than the reference value, the comparator outputs a high-level signal, and the high-level signal is divided into four signals, two of which are directly used as control signals of the second relay and the fourth relay to control the second branch of the second conversion topology to be connected to the main circuit, and the other two signals are passed through the NOT gate to obtain two low-level signals as control signals of the first relay and the third relay to control the first branch of the second conversion topology to be connected to the main circuit.

[0034] Furthermore, it also includes: an energy storage module;

[0035] The energy storage module is connected to the photovoltaic through the main circuit;

[0036] The energy storage module is used to store excess photovoltaic power and directly supply power to the load under set working conditions.

[0037] In summary, the present invention provides a variable structure photovoltaic electric vehicle charging pile, including: photovoltaic, main circuit, control circuit and topology selection circuit; the main circuit is used to convert the photovoltaic output into a controllable output under the control of the control circuit to power the load; the main circuit is provided with two conversion topologies with different voltage gain ranges; the topology selection circuit obtains the output after the main circuit conversion, and compares the current output value with the reference value, and selects the conversion topology corresponding to the voltage gain range according to the size relationship between the two. The charging pile of the present invention has two working topologies and a wide voltage range. At the same time, different topological structures are selected to meet the load requirements when the load and input change, which has strong adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 A topological diagram of a variable structure photovoltaic electric vehicle charging pile provided in an embodiment of the present invention;

[0040] Figure 2 A topological structure diagram of a first conversion topology connected to a main circuit provided by an embodiment of the present invention;

[0041] Figure 3 A topological structure diagram of a second conversion topology connected to a main circuit provided by an embodiment of the present invention;

[0042] Figure 4 A schematic diagram of a charging mode when there is no electric vehicle provided by an embodiment of the present invention;

[0043] Figure 5 A schematic diagram of the power supply mode of the variable structure photovoltaic electric vehicle charging pile energy storage module provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] An embodiment of the present invention provides a variable-structure photovoltaic electric vehicle charging pile, including: photovoltaic, main circuit, control circuit and topology selection circuit; the main circuit is used to convert the photovoltaic output into a controllable output under the control of the control circuit to power the load; the main circuit is provided with two conversion topologies with different voltage gain ranges; the topology selection circuit obtains the output after the main circuit conversion, and compares the current output value with the reference value, and selects the conversion topology corresponding to the voltage gain range according to the size relationship between the two.

[0046] In one embodiment of the present invention, the topology selection circuit includes: a group of relays and comparators;

[0047] The comparator is used to compare the transformed output of the main circuit with a reference value, and if the output is less than the reference value, a signal for switching to the first topology is generated; otherwise, a signal for switching to the second topology is generated;

[0048] A group of relays is connected to the main circuit, and is used to switch the conversion topology of the main circuit to the first conversion topology according to the switching first topology signal or to switch the conversion topology of the main circuit to the second conversion topology according to the switching second topology signal.

[0049] The first conversion topology, the second conversion topology and their switching are described in detail below through further embodiments.

[0050] In a further embodiment of the present invention, the first conversion topology may include a first inductor L1, a second inductor L2, a first switch tube S1 and a second switch tube S2;

[0051] The first inductor L1 is used as a first branch, one end of which is connected to the negative electrode of the first switch tube S1 and then connected to the photovoltaic end, and the other end of which is connected to the negative electrode of the second switch tube S2 and then connected to the load end;

[0052] The second inductor L2 serves as the second branch, one end of which is connected to the positive electrode of the first switch tube S1 and then connected to the photovoltaic end, and the other end of which is connected to the positive electrode of the second switch tube S2 and then connected to the load end;

[0053] The first switch tube S1 and the second switch tube S2 are both controlled by a control circuit.

[0054] Figure 1 The topological structure diagram of the variable structure photovoltaic electric vehicle charging pile. Among them, the load end includes an electric vehicle. The present invention aims to provide a charging pile with a wider voltage regulation range, which is mainly achieved through two conversion topologies set by the main circuit. Therefore, the circuit design of the photovoltaic end and the load end refers to the prior art and will not be repeated here.

[0055] Figure 2 This is the topological structure diagram of the first conversion topology connected to the main circuit. According to its structure, the voltage gain of topology 1 is:

[0056]

[0057] Wherein, G1 is the voltage gain of the first conversion topology, and d is the duty cycle of the switch tube controlled by the control circuit.

[0058] When the load or input changes, such as the addition of electric vehicles and the uncertainty of new energy photovoltaics, the output voltage V o The load demand may not be met, so the structure needs to be changed to meet the load demand. The real-time output voltage V o The value of the reference voltage V ref2 After comparison by the comparator, a switching topology signal is generated. For topology 1, when V o <V ref2 When the first topology is switched, the comparator generates a signal for switching the first topology, so that a group of relays control the first conversion topology to be connected to the main circuit.

[0059] In a further embodiment of the present invention, the second conversion topology includes a first coupled inductor, a second coupled inductor, a first switch tube S1 and a second switch tube S2;

[0060] The first coupling inductor is used as the first branch, one end of which is connected to the negative electrode of the first switch tube S1 and then connected between the photovoltaic end and the load end, and the other end of which is connected to the negative electrode of the second switch tube S2 and then connected between the photovoltaic end and the load end;

[0061] The second coupled inductor serves as the second branch, one end of which is connected to the positive electrode of the first switch tube S1 and then connected between the photovoltaic end and the load end, and the other end of which is connected to the positive electrode of the second switch tube S2 and then connected between the photovoltaic end and the load end;

[0062] The first switch tube S1 and the second switch tube S2 are both controlled by a control circuit.

[0063] Further, the first coupled inductor and the second coupled inductor each include two inductors and two diodes.

[0064] For the first coupled inductor, the first inductor L of the two inductors 11 The same-name end of the first switch tube S1 is connected to the cathode of the first switch tube S1 and then connected between the photovoltaic end and the load end. The opposite-name end is connected to the anodes of the two diodes D1 and D2 respectively.

[0065] The second inductor L of the two inductors 12 The same-name end is connected to the cathode of one of the two diodes D2, and the opposite-name end is connected to the cathode of the other diode D1 as the other end of the branch, which is connected to the negative electrode of the second switch tube S2 and then connected between the photovoltaic end and the load end.

[0066] For the second coupled inductor, the first inductor L21 The same-name end of the first switch tube S1 is connected to the positive electrode of the first switch tube S1 and then connected between the photovoltaic end and the load end. The opposite-name end is connected to the anodes of the two diodes D3 and D4 respectively.

[0067] The second inductor L of the two inductors 22 The same-name end is connected to the cathode of one of the two diodes D4, and the opposite-name end is connected to the cathode of the other diode D3 as the other end of the branch, which is connected to the positive electrode of the second switch tube S2 and then connected between the photovoltaic end and the load end.

[0068] Figure 3 This is the topological structure diagram of the second conversion topology connected to the main circuit. According to its structure, the voltage gain of topology 2 is:

[0069]

[0070] Wherein, G2 is the voltage gain of the second conversion topology, d is the duty cycle of the control circuit controlling the switch tube, and n is the turns ratio between the two inductors.

[0071] When the main circuit outputs voltage V o The value of the reference voltage V ref2 The comparator generates a switching topology signal. For topology 2, when V o Not less than V ref2 When the first topology is switched, the comparator generates a signal for switching the first topology, so that a group of relays control the first conversion topology to be connected to the main circuit.

[0072] In order to achieve stable switching control, in a further embodiment of the present invention, the number of relays is set to 4. Among them, the first branch of the first conversion topology is connected to the main circuit through a static contact of the first relay K1 and a static contact of the third relay K3, and the second branch is connected to the main circuit through a static contact of the second relay K2 and a static contact of the fourth relay K4. The first branch of the second conversion topology is connected to the main circuit through another static contact of the first relay K1 and another static contact of the third relay K3, and the second branch is connected to the main circuit through another static contact of the second relay K2 and another static contact of the fourth relay K4.

[0073] Based on the above design, the comparator compares and generates the signals of relays K1-K4, and the topology selection circuit selects the topology according to the relay signals, which is divided into the following two states:

[0074] (A) Topology 1: V o <V ref2 , high level signal 1 is connected to relays K1 and K3, and low level signal 0 is connected to relays K2 and K4;

[0075] (B) Topology 2: V ref2 <V o , low level signal 0 is connected to relays K1 and K3, and high level signal 1 is connected to relays K2 and K4.

[0076] For state A, when V o <V ref2 When V ref2 The specific value should be set according to the actual working conditions. The real-time output voltage V o With reference voltage V ref2 Comparison is made through the comparator, and the output is a low-level signal 0. a1 and a3 pass through the NOT gate to obtain two high-level signals 11, and are connected to relays K1 and K3. At this time, relays K1 and K3 are in action, K1 is connected to one end of the inductor L1 branch, and K3 is connected to the other end of the inductor L1 branch; a2 and a4 obtain a low-level signal 0, and are connected to relays K2 and K4. At this time, relays K2 and K4 are in action, K2 is connected to one end of the inductor L2 branch, and K4 is connected to the other end of the inductor L2 branch. The variable-structure photovoltaic electric vehicle charging pile selects topology 1, such as Figure 2 As shown, the voltage gain at this time is The photovoltaic input charges the energy storage module through topology 1 and supplies power to the electric vehicle. The drive circuit generates duty cycle signals d1 and d2 through the voltage error signal processing and PWM link of the main control circuit, drives the switch tubes S1 and S2, and increases the working stability of the circuit.

[0077] For state B, when V ref2 <V o When V ref2 The specific value should be set according to the actual working conditions. The real-time output voltage V o With reference voltage V ref2 The comparator compares the two signals and outputs a high-level signal 1. a1 and a3 pass through the NOT gate to obtain two low-level signals 00, which are then connected to relays K1 and K3. At this time, relays K1 and K3 are activated, and K1 is connected to the coupling inductor L. 11 The same-name end of the branch, K3 is connected to the coupled inductor L 12 The opposite end of the branch is connected to the cathode of the diode D1; a2 and a4 obtain a high level signal 1 and are connected to relays K2 and K4. At this time, relays K2 and K4 are activated, and K2 is connected to the coupling inductor L 22 The opposite end of the branch is connected to the cathode of diode D3, and K4 is connected to the coupling inductor L 21 The same-name end of the branch, the variable-structure photovoltaic electric vehicle charging pile selects topology 2, such as Figure 3 As shown, the voltage gain at this time is The photovoltaic input charges the energy storage module through topology 2 and supplies power to the electric vehicle. The drive circuit generates duty cycle signals d1 and d2 through the voltage error signal processing and PWM link of the main control circuit, drives the switch tubes S1 and S2, and increases the working stability of the circuit.

[0078] In addition, the variable structure photovoltaic electric vehicle charging pile is also equipped with an energy storage module. Figure 4 As shown, the new energy photovoltaic charges the energy storage module through the main circuit. Figure 5 As shown, new energy has problems such as uncertainty and randomness, especially in complex working conditions such as bad weather, night, and circuit failure. The energy storage module supplies power to electric vehicles to ensure the normal operation of the circuit.

[0079] The variable structure photovoltaic electric vehicle charging pile provided by the present invention has two working topologies, a wide voltage range, and can select different topologies to meet load requirements when the load and input change, and has strong adaptability. In addition, under complex working conditions such as circuit failure, the energy storage module ensures the normal operation of the circuit, and has high reliability.

[0080] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A variable structure photovoltaic electric vehicle charging pile, characterized in that: include: Photovoltaic, main circuit, control circuit and topology selection circuit; The main circuit is used to convert the photovoltaic output into a controllable output under the control of the control circuit, so as to supply power to the load; The main circuit is provided with two conversion topologies with different voltage gain ranges; The topology selection circuit obtains the output of the main circuit after transformation, compares the current output value with the reference value, and selects the transformation topology corresponding to the voltage gain range according to the magnitude relationship between the two; The topology selection circuit includes: a group of relays and comparators; The comparator is used to compare the transformed output of the main circuit with the reference value, and if the output is less than the reference value, a signal for switching to the first topology is generated; otherwise, a signal for switching to the second topology is generated; The group of relays is connected to the main circuit, and is used to switch the conversion topology of the main circuit to the first conversion topology according to the switching first topology signal or to switch the conversion topology of the main circuit to the second conversion topology according to the switching second topology signal; The first conversion topology includes a first inductor, a second inductor, a first switch tube and a second switch tube; The first inductor is used as a first branch, one end of which is connected to the negative electrode of the first switch tube and then connected between the photovoltaic end and the load end, and the other end of which is connected to the negative electrode of the second switch tube and then connected between the photovoltaic end and the load end; The second inductor is used as a second branch, one end of which is connected to the positive electrode of the first switch tube and then connected between the photovoltaic end and the load end, and the other end of which is connected to the positive electrode of the second switch tube and then connected between the photovoltaic end and the load end; The first switch tube and the second switch tube are both controlled by the control circuit.

2. The variable structure photovoltaic electric vehicle charging pile according to claim 1, characterized in that: The voltage gain of the first conversion topology is as follows: ； in, is the voltage gain of the first conversion topology, The control circuit controls the duty cycle of the switch tube.

3. The variable structure photovoltaic electric vehicle charging pile according to claim 1, characterized in that: The second conversion topology includes a first coupled inductor, a second coupled inductor, a first switch tube and a second switch tube; The first coupled inductor is used as a first branch, one end of which is connected to the negative electrode of the first switch tube and then connected between the photovoltaic end and the load end, and the other end of which is connected to the negative electrode of the second switch tube and then connected between the photovoltaic end and the load end; The second coupled inductor serves as a second branch, one end of which is connected to the positive electrode of the first switch tube and then connected between the photovoltaic end and the load end, and the other end of which is connected to the positive electrode of the second switch tube and then connected between the photovoltaic end and the load end; The first switch tube and the second switch tube are both controlled by the control circuit.

4. The variable structure photovoltaic electric vehicle charging pile according to claim 3 is characterized in that: The first coupled inductor and the second coupled inductor each include two inductors and two diodes; The same-name end of the first inductor of the two inductors is used as one end of the branch, and the opposite-name end is connected to the anodes of the two diodes respectively; The same-name end of the second inductor of the two inductors is connected to the cathode of one of the two diodes, and the opposite-name end is connected to the cathode of the other diode to serve as the other end of the branch.

5. The variable structure photovoltaic electric vehicle charging pile according to claim 4, characterized in that: The voltage gain of the second conversion topology is as follows: ； in, is the voltage gain of the second conversion topology, The control circuit controls the duty cycle of the switch tube. is the turns ratio between the two inductors.

6. The variable structure photovoltaic electric vehicle charging pile according to claim 1, characterized in that: The number of relays in the group is set to 4, wherein the first branch of the first conversion topology is connected to the main circuit through a static contact of the first relay and a static contact of the third relay, and the second branch is connected to the main circuit through a static contact of the second relay and a static contact of the fourth relay, the first branch of the second conversion topology is connected to the main circuit through another static contact of the first relay and another static contact of the third relay, and the second branch is connected to the main circuit through another static contact of the second relay and another static contact of the fourth relay.

7. The variable structure photovoltaic electric vehicle charging pile according to claim 6, characterized in that: The process of the topology selection circuit selecting a conversion topology corresponding to a voltage gain range specifically includes: When the output of the main circuit after transformation is less than the reference value, the comparator outputs a low-level signal, and the low-level signal is divided into four signals, two of which are directly used as control signals of the second relay and the fourth relay to control the second branch of the first transformation topology to connect to the main circuit, and the other two signals are passed through the NOT gate to obtain two high-level signals as control signals of the first relay and the third relay to control the first branch of the first transformation topology to connect to the main circuit; When comparing that the output of the main circuit after transformation is not less than the reference value, the comparator outputs a high-level signal, and the high-level signal is divided into four signals, two of which are directly used as control signals of the second relay and the fourth relay to control the second branch of the second conversion topology to be connected to the main circuit, and the other two signals are passed through the NOT gate to obtain two low-level signals as control signals of the first relay and the third relay to control the first branch of the second conversion topology to be connected to the main circuit.

8. The variable structure photovoltaic electric vehicle charging pile according to claim 1, characterized in that: Also includes: Energy storage module; The energy storage module is connected to the photovoltaic through the main circuit; The energy storage module is used to store excess photovoltaic power and directly supply power to the load under set working conditions.

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