Direct current converter and direct current charging pile
By connecting two switch tubes and two original winding winding in the DC converter, the voltage of the DC voltage is achieved, and the problem of high voltage of the switching tube is solved, and the difficulty and cost of selection are reduced.
Patent Information
- Application Number
- CN202420856783.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-23
- Publication Date
- 2025-01-28
- Estimated Expiration
- 2034-04-23
AI Technical Summary
In existing DC converters, the switching tubes bear high voltage, which leads to difficulty in selecting and high cost.
Design a DC transformation, connects the two switch tubes and two original winding winding, connects to both ends of the DC source, to achieve the voltage of the DC voltage, thereby reducing the voltage of each switch tube.
Through pressure technology, the difficulty and cost of the selection of the switch tube are reduced, and the design of the DC transformer is optimized.
Smart Images
Figure CN222423523U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of power electronics technology, and in particular to a DC converter and a DC charging pile. Background Art
[0002] In the field of power electronics, many high-voltage DC power supplies need to be converted into low-voltage DC power supplies. For example, the power supply for equipment control generally uses low-voltage DC, that is, the auxiliary power supply is generally low-voltage DC. Another example is the application scenario of DC charging piles. The power supply for the control, cooling fan, etc. corresponding to the internal power converter of the DC charging pile is generally obtained from the DC bus of the rectifier and then the flyback circuit is used to obtain low-voltage DC.
[0003] However, the current DC bus voltage is getting higher and higher. For example, some voltages reach thousands of volts. Some isolation converters also have reflected voltage. The DC bus voltage is superimposed on the reflected voltage, resulting in a higher voltage on the switch tube connected in series with the primary winding. This is not conducive to the selection of the switch tube. The higher the voltage resistance level of the switch tube, the higher the cost of the switch tube. Utility Model Content
[0004] In view of this, the present application provides a DC converter and a DC charging pile, which can reduce the voltage borne by the switching tube, thereby reducing the selection cost of the switching tube.
[0005] The DC converter provided in an embodiment of the present application includes: a first switch tube, a second switch tube, a transformer, a rectifier circuit and a sampling resistor; the transformer includes: a first primary winding, a second primary winding and a secondary winding; the first primary winding, the first switch tube, the second primary winding, the second switch tube and the sampling resistor are connected in series and connected between the positive and negative electrodes of a DC source; the first end of the secondary winding is connected to the first end of the rectifier circuit, the second end of the rectifier circuit is used as a positive output end, and the second end of the secondary winding is used as a negative output end.
[0006] In a possible implementation manner, the number of turns of the first primary winding is the same as the number of turns of the second primary winding; and the first switch tube and the second switch tube are of the same type.
[0007] In a possible implementation manner, the same-name end of the first primary winding is connected to the positive electrode of the DC source, and the opposite-name end of the first primary winding is connected to the same-name end of the second primary winding through the first switch tube.
[0008] In a possible implementation manner, the first end of the secondary winding is an opposite-name end, and the second end of the secondary winding is a like-name end.
[0009] In a possible implementation, the rectifier circuit includes a diode, an anode of the diode is connected to the first end of the secondary winding, and a cathode of the diode serves as the positive output end.
[0010] A possible implementation also includes: a controller; the controller is connected to the sampling resistor, the first switch tube and the second switch tube; the controller is used to control the switching state of the first switch tube and the second switch tube according to the current on the sampling resistor.
[0011] In one possible implementation, the switching state of the first switch tube is the same as the switching state of the second switch tube. When the first switch tube and the second switch tube are turned on, the first primary winding and the second primary winding of the converter store energy; when the first switch tube and the second switch tube are turned off, the first primary winding and the second primary winding of the converter release energy to the secondary winding.
[0012] In a possible implementation manner, the DC converter is a step-down DC converter.
[0013] An embodiment of the present application also provides a DC charging pile, including the DC converter introduced above; and also including: a DC load; the DC converter is used to step down the voltage of the DC source and then supply power to the DC load; the DC load is a DC load in the DC charging pile.
[0014] In a possible implementation, the DC load is a control circuit or a heat dissipation device in the DC charging pile.
[0015] It can be seen that this application has the following beneficial effects:
[0016] The DC converter provided in the embodiment of the present application includes two switching tubes, two primary windings and one secondary winding. The two switching tubes and the two primary windings are connected in series and connected to the two ends of the DC source. The switching tubes and the primary windings correspond to each other one by one. Since the two primary windings can divide the voltage of the DC source, the two switching tubes must withstand the voltage of the entire DC source. The voltage borne by each switching tube is reduced, and then a switching tube with a lower voltage resistance can be selected, which is beneficial to the selection of the switching tube and reduces the cost of the switching tube. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 is a schematic diagram of a DC converter;
[0018] Figure 2 A schematic diagram of a DC converter provided in an embodiment of the present application;
[0019] Figure 3 is a schematic diagram of yet another DC converter;
[0020] Figure 4 A schematic diagram of a DC charging pile provided in an embodiment of the present application. DETAILED DESCRIPTION
[0021] In order to enable those skilled in the art to better understand the technical solution provided by the embodiments of the present application, a specific DC converter is first introduced below with reference to the accompanying drawings.
[0022] See also Figure 1 , which is a schematic diagram of a DC converter.
[0023] Figure 1 The figure shows an isolation converter, which is a DC-DC converter and is often used as an auxiliary power supply. The DC converter includes a switch tube Q1, a sampling resistor R1, a transformer T1 and a diode D1.
[0024] Figure 1 Since the same-named ends of the primary winding N1 and the secondary winding N2 are in opposite positions, Figure 1 The DC converter shown is a flyback converter.
[0025] Vout is the output voltage. The controller outputs a drive signal to control the on and off of Q1, thereby transferring the energy of the primary winding to the secondary winding.
[0026] For ease of understanding, for example, when the voltage of the DC source DC is designed according to the minimum value Vdcmin of 360V, the maximum value Vdcmax of 1000V, the output voltage Vout of 12V, the turns ratio of 10, the maximum duty cycle Dmax of 45%, and the parasitic parameters such as the leakage inductance of the transformer are not considered, the reflected voltage Vor = (Dmax / 1-Dmax)*Vdcmin. At this time, the highest voltage that Q1 withstands Vdsmax = (Vor+Vdcmax) / 0.85 is approximately equal to 1500V. Therefore, the selection of Q1 can be selected from a switch tube with a withstand voltage of about 1500V. The withstand voltage of most switch tubes is several hundred volts. Therefore, Figure 1 The selection of the switch tube in the DC converter shown is difficult and the cost of the switch tube is relatively high.
[0027] In order to reduce the voltage borne by the switching tube, the DC converter provided in the embodiment of the present application samples two switching tubes connected in series, and each switching tube corresponds to a primary winding, so that the DC source can be divided and the voltage borne by each switching tube is reduced, thereby making the selection of the switching tube easier and reducing the selection cost of the switching tube.
[0028] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the embodiments of the present application are further described in detail below in conjunction with the accompanying drawings and specific implementation methods.
[0029] See also Figure 2 , which is a schematic diagram of a DC converter provided in an embodiment of the present application.
[0030] The DC converter provided in the embodiment of the present application is characterized by comprising: a first switch tube Q1, a second switch tube Q2, a transformer T1, a rectifier circuit and a sampling resistor R1; the transformer T1 comprises: a first primary winding N1, a second primary winding N2 and a secondary winding N3.
[0031] The first primary winding N1, the first switch tube Q1, the second primary winding N2, the second switch tube Q2 and the sampling resistor R1 are connected in series and connected between the positive electrode and the negative electrode of the direct current source DC;
[0032] The embodiment of the present application does not specifically limit the specific types of the first switch tube Q1 and the second switch tube Q2. For example, they can be a Metal-Oxide-Semiconductor Field-Effect Transistor (MOS) or an Insulate-Gate Bipolar Transistor (IGBT).
[0033] The first end of the secondary winding N3 is connected to the first end of the rectifier circuit, the second end of the rectifier circuit serves as the positive output end, and the second end of the secondary winding serves as the negative output end. The output voltage of the DC converter is Vout. The embodiment of the present application does not specifically limit the specific implementation form of the rectifier circuit. Figure 2 In the description, the rectifier circuit including the diode D1 is taken as an example. It should be understood that the rectifier circuit may also be a rectifier circuit of other topologies, such as half-wave rectification or full-bridge rectification. Figure 2 The middle rectifier circuit comprises a diode D1, an anode of the diode D1 is connected to the first end of the secondary winding N3, and a cathode of the diode D1 serves as a positive output end of the DC converter.
[0034] The DC converter provided in the embodiment of the present application includes two primary windings connected in series, and therefore, the DC voltage of the DC source can be divided. It should be understood that the closer the number of turns of the two primary windings connected in series is, the closer the DC voltage of the two primary windings connected in series is. In order to make the voltages borne by the two switching tubes the same, the number of turns of the first primary winding and the number of turns of the second primary winding can be set to be the same; in this way, the type of the first switching tube and the type of the second switching tube can be the same, which is more convenient for control. In addition, it should be understood that if the number of turns of the first primary winding and the second primary winding is slightly different, it will not affect the selection of the first switching tube and the second switching tube. Since the voltage borne by each switching tube is reduced, the selection of the switching tube is convenient.
[0035] For example, if the DC voltage is 1000V and N1 and N2 have the same number of turns, 1000V will be evenly divided, so Q1 and Q2 will each withstand a voltage of 500V, which is beneficial for the selection of Q1 and Q2.
[0036] For example, when the voltage of the DC source DC is designed according to the minimum value Vdcmin of 360V, the maximum value Vdcmax of 1000V, the output voltage Vout of 12V, the turns ratio of 10, the maximum duty cycle Dmax of 45%, and the parasitic parameters such as the leakage inductance of the transformer are not considered, the reflected voltage Vor = (Dmax / 1-Dmax)*Vdcmin. At this time, the highest voltage Vdsmax that Q1 withstands is approximately equal to 760V, so the selection of Q1 and Q2 can be selected to be a switch tube of about 800V. Because N1 and N2 are connected in series, only one set of current sampling resistors is needed for current monitoring on the input side. Therefore, the DC converter provided in the embodiment of the present application can optimize the selection of the switch tube.
[0037] The embodiment of the present application does not specifically limit the specific form of the DC converter, for example, it can be a forward converter or a flyback converter.
[0038] In the DC converter provided in the embodiment of the present application, the same-name end of the first primary winding N1 is connected to the positive electrode of the DC source, and the opposite-name end of the first primary winding N1 is connected to the same-name end of the second primary winding N2 through the first switch tube Q1.
[0039] The first end of the secondary winding N3 is an opposite-name end, and the second end of the secondary winding N3 is a same-name end, that is, the positions of the same-name ends of N1, N2 and N3 introduced above indicate that Figure 2 The DC converter shown is a flyback converter.
[0040] Continue to see Figure 2 ,The DC converter provided in the embodiment of the present application further includes: a controller ,100;
[0041] The controller 100 connects the sampling resistor R1 and the first switch tube Q1 and the second switch tube Q2;
[0042] The controller 100 is used to control the first switch tube Q1 and the second switch tube Q2 according to the current on the sampling resistor R1.
[0043] It should be understood that the switching state of the first switch tube Q1 is the same as the switching state of the second switch tube Q2. That is, when Q1 is turned on, Q2 is also turned on. When Q1 is turned off, Q2 is also turned off. When Q1 and Q2 are turned on at the same time, current flows through N1 and N2, and N1 and N2 of the transformer T1 store energy. When Q1 and Q2 are turned off at the same time, the energy stored in N1 and N2 of the transformer T1 is then transferred to the output end through the secondary winding N3. The controller can complete the transfer of energy from the primary winding of the transformer to the secondary winding by continuously controlling the simultaneous actions of Q1 and Q2.
[0044] The embodiment of the present application does not specifically limit the specific implementation method of the controller, for example, it can be a single-chip microcomputer or a microprocessor.
[0045] The embodiment of the present application does not specifically limit the type of DC converter, for example, it may be a buck converter, for example, reducing a voltage of several hundred volts to an output of several tens of volts or more than ten volts.
[0046] In order to further highlight the beneficial effects of the DC converter provided in the embodiment of the present application, another DC converter is introduced below.
[0047] See also Figure 3 , which is a schematic diagram of another DC converter.
[0048] from Figure 3 and Figure 2 In comparison, Figure 3 There is a DC bus midpoint O in the circuit, and there are two sampling resistors, R1 and R2. The DC bus midpoint O evenly divides the DC voltage. However, Figure 3 compared to Figure 2 For example, it is necessary to add a set of current sampling resistors. At this time, it is also necessary to consider that R1 and R2 do not share a common ground, and an isolation circuit needs to be introduced into one of the sets of current sampling resistors. Figure 2 Compared with the solution shown in the figure, the hardware cost is increased. Figure 1 For the solution, the overall cost advantage is not great.
[0049] The embodiments of the present application provide Figure 2 The DC converter does not need to introduce the DC bus midpoint, and only requires one sampling resistor, corresponding to one current sampling circuit, so there is no isolation circuit.
[0050] Based on a DC converter provided in the above embodiment, the embodiment of the present application further provides a DC charging pile, which is described in detail below with reference to the accompanying drawings.
[0051] See also Figure 4 , which is a schematic diagram of a DC charging pile provided in an embodiment of the present application.
[0052] The DC charging pile provided in the embodiment of the present application includes the DC converter 100 introduced in the above embodiment; and also includes: a DC load 200;
[0053] The DC converter 100 is used to step down the voltage of the DC source and then supply power to the DC load 200;
[0054] The DC load 200 is a DC load in a DC charging pile.
[0055] In a possible implementation, the DC load 200 is a control circuit or a heat dissipation device in the DC charging pile.
[0056] Since the DC charging pile provided in the embodiment of the present application includes a DC converter, the DC converter can be used as an auxiliary power supply inside the DC charging pile to power the DC load in the DC charging pile. Since the selection of the switch tube in the DC converter is easy and the cost is low, the cost of the entire DC charging pile can be reduced. In addition, since the currents flowing through the two switch tubes are the same, only one resistor is needed, which saves the size of the hardware circuit and can also save the cost of the hardware circuit.
[0057] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.
[0058] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A DC converter, characterized in that: include: A first switch tube, a second switch tube, a transformer, a rectifier circuit and a sampling resistor; the transformer comprises: a first primary winding, a second primary winding and a secondary winding; The first primary winding, the first switch tube, the second primary winding, the second switch tube and the sampling resistor are connected in series and connected between the positive electrode and the negative electrode of the DC source; The first end of the secondary winding is connected to the first end of the rectifier circuit, the second end of the rectifier circuit serves as a positive output end, and the second end of the secondary winding serves as a negative output end.
2. The DC converter according to claim 1, characterized in that: The number of turns of the first primary winding is the same as the number of turns of the second primary winding; The first switch tube and the second switch tube are of the same type.
3. The DC converter according to claim 1 or 2, characterized in that: The same-name end of the first primary winding is connected to the positive electrode of the DC source, and the opposite-name end of the first primary winding is connected to the same-name end of the second primary winding through the first switch tube.
4. The DC converter according to claim 3, characterized in that: The first end of the secondary winding is an opposite-name end, and the second end of the secondary winding is a like-name end.
5. The DC converter according to claim 1 or 2, characterized in that: The rectifier circuit includes a diode, an anode of the diode is connected to the first end of the secondary winding, and a cathode of the diode serves as the positive output end.
6. The DC converter according to claim 1 or 2, characterized in that: Also includes: Controller; The controller is connected to the sampling resistor, the first switch tube and the second switch tube; The controller is used to control the switching states of the first switch tube and the second switch tube according to the current on the sampling resistor.
7. The DC converter according to claim 6, characterized in that: The switching state of the first switching tube is the same as the switching state of the second switching tube. When the first switching tube and the second switching tube are turned on, the first primary winding and the second primary winding of the converter store energy; when the first switching tube and the second switching tube are turned off, the first primary winding and the second primary winding of the converter release energy to the secondary winding.
8. The DC converter according to claim 1 or 2, characterized in that: The DC converter is a step-down DC converter.
9. A DC charging pile, characterized in that: The DC converter comprises any one of claims 1 to 8; and further comprises: a DC load; The DC converter is used to step down the voltage of the DC source and then supply power to the DC load; The DC load is a DC load in a DC charging pile.
10. The DC charging pile according to claim 9, characterized in that: The DC load is a control circuit or a heat dissipation device in the DC charging pile.