One-way DC converter
By connecting the primary winding of the transformer to the input power supply and the secondary winding to the series filter capacitor in a single-pass DC-DC converter, and introducing an additional winding, the problems of limited output voltage regulation range and large dynamic loss are solved, achieving full-cycle energy transmission and loss reduction.
Patent Information
- Application Number
- CN202480015820.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-02-02
- Filing Date
- 2024-02-02
- Publication Date
- 2025-11-11
AI Technical Summary
It is known that the output voltage adjustment range of a DC-DC converter is limited, a large air gap is required in the transformer magnetic circuit, and the current of the adjustment key is trapezoidal, resulting in large dynamic losses.
In a single-pass DC-DC converter, the primary winding of the transformer is connected to the input DC power supply via an adjustment key, and the secondary winding is connected to two series-connected filter capacitors via rectifier diodes. The load is connected in parallel with the filter capacitors, and an additional winding is introduced to optimize the magnetization and demagnetization of the transformer.
It enables energy transfer to the load throughout the entire converter cycle, expands control and power capabilities, reduces dynamic losses when the regulator is turned on, and the rectangular shape of the current flowing through the regulator reduces losses when it is turned off.
Smart Images
Figure CN120937236A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to electrical engineering, and more particularly to a single-pass DC-DC converter that can be used in secondary power supply systems to convert, stabilize, and regulate DC output power, while providing electrical isolation from the input DC power. Background Technology
[0002] It is known that DC-DC converters have the characteristic of electrically separating the output DC power from the input DC power [1].
[0003] The known disadvantages of DC-to-DC converters are that the output voltage adjustment range is limited, the requirements for the air gap in the transformer's magnetic circuit are high, the current flowing through the adjustment key is trapezoidal, and the dynamic loss of the adjustment key is large when it is turned on and off.
[0004] In terms of technical essence, the device most similar to the proposed device is a DC-DC converter, whose energy is transferred to the output circuit on the return (flyback) route. It includes the primary winding of a transformer, which is connected to the terminal of the input DC power supply via a control key. The secondary winding of the transformer is connected to a capacitor filter via a rectifier diode and is connected in parallel with the load [1].
[0005] The disadvantage of this converter is that energy is only transferred to the load during the time interval when the regulator is closed, which limits the regulation capability of the voltage converter, requires a fairly large air gap size in the magnetic circuit, and generates related losses in the transformer. During the time interval when the regulator is open and closed, a large dynamic power loss is generated in the regulator, which is related to the trapezoidal shape of the current flowing through the regulator. Summary of the Invention
[0006] The purpose of this invention is to eliminate the above-mentioned disadvantages.
[0007] The above objective is achieved in the following manner: In a single-pass DC-DC converter, the primary winding of the transformer is connected to the terminal of the input DC power supply via an adjustment key, the secondary winding of the transformer is connected to the first filter capacitor via a rectifier diode, and is connected to the second filter capacitor connected in series with the first filter capacitor via another rectifier diode, and the load is connected in parallel with the filter capacitor. Attached Figure Description
[0008] Figure 1 and Figure 2 The circuit schematic of the proposed single-pass DC-DC converter embodiment is shown in the figure. Figure 1 The circuit schematic of a single-pass DC-DC converter is shown in the figure; Figure 2 The circuit diagram of a single-pass DC-DC converter with an additional winding is shown. Detailed Implementation
[0009] in( Figure 1 The primary winding 1 of transformer 2 is connected to the positive terminal of the DC input source, and the end of the primary winding 1 is connected to the negative terminal of the DC input source via a switch 3 controlled by pulse width controller 10. The anode of rectifier diode 5 is connected to the beginning of the secondary winding 4 of transformer 2, and its cathode is connected to one terminal of capacitor 6. The second terminal of capacitor 6 is connected to the end of winding 4. One end of winding 4 is connected to one terminal of capacitor 7, and the other end of capacitor 7 is connected to the anode of rectifier diode 8. The cathode of rectifier diode 8 is connected to the beginning of winding 4. Load 9 is connected in parallel with series capacitors 6 and 7.
[0010] exist Figure 2 In the transformer 2, one end of the additional lead winding 11 is connected to one terminal of the capacitor 7, the other end of the capacitor 7 is connected to the anode of the rectifier diode 8, and the cathode of the rectifier diode 8 is connected to the beginning of the winding 4.
[0011] We will consider the operating principle of the proposed single-pass AC converter based on the following assumptions: ideal key elements, stable operating mode, and continuous change of magnetic flux in the core of transformer 2.
[0012] We denote the duration of the conduction state of switch 3 relative to period T as D. At this time, switch 3, made of a field-effect transistor (MOSFET), is in the closed state, and energy is transferred to the load through the forward-biased rectifier diode 5 and winding 4. Meanwhile, due to the charge balance of capacitor 6 at time intervals DT and (1-D)T, the current I... L / D flows through rectifier diode 5, where I L Given the load current, the voltage across capacitor 7 is given by the expression nV. IN Determine, where n is the turns ratio of winding 4 to winding 1.
[0013] After switch 3 is disconnected, the voltage on the winding of transformer 2 changes sign within the time interval (1-D)T. As a result, rectifier diode 5 turns off and diode 8 turns on. The energy accumulated in transformer 2 during the time interval DT when switch 3 is on is output to capacitor 7 through rectifier diode 8 and the secondary winding 4 of transformer 2. At this time, due to the charge balance of capacitor 7, the current I... L / (1-D) flows through rectifier diode 8, and the voltage across capacitor 7 is given by the expression nV. IN D / (1-D) is determined. The output voltage nV across the load is determined. IN / (1-D) is determined by the sum of the voltages across the series capacitors 6 and 7.
[0014] When energy is transferred to the output circuit during time interval DT, two processes occur when switch 3 is turned on: one is related to the energy transfer from the input power supply V along the primary winding 1 of transformer 2.IN Magnetization and the voltage nV along the secondary winding 4 from capacitor 6 IN Magnetization is also related. As a result of this magnetization, the current increases linearly in proportion. In the secondary winding 4, this increase in current causes a decrease in the current flowing through the rectifier diode 5, which is in a conducting state during this time interval. The linear decrease in the current flowing through the rectifier diode 5 is transferred to the primary winding 1 and compensates for the linear increase in the current flowing through the primary winding 1, which causes the current flowing through the regulating key 3 to become rectangular.
[0015] The second process is related to the timing of opening control key 3. When control key 3 is closed, the voltage on the transformer winding reverses polarity, causing rectifier diode 8 to disconnect and rectifier diode 5 to connect. However, there is a time delay between the connection of rectifier diode 5 and the conduction of control key 3. This delay is due to the finite time of voltage change on transformer winding 2 and the fact that the positive potential at the cathode of rectifier diode 5 is equal to nV. IN Caused by.
[0016] The time delay in energy transfer to the output circuit when the adjustment key 3 is turned on causes the leading edges of the current and voltage on the adjustment key 3 to separate, thereby reducing the dynamic loss when turned on.
[0017] As mentioned above, the current flowing through the adjustment key 3 is essentially rectangular, which reduces the losses of the adjustment key 3 when it is turned off, since the switch is turned off at a lower current.
[0018] As can be seen from the working principle of this single-pass DC-DC converter, the magnetization and demagnetization of transformer 2 occur along the output winding 4 of transformer 2. To optimize transformer 2 and reduce its gaps, an additional winding 11 can be introduced to magnetize and demagnetize from different windings, such as... Figure 2 As shown.
[0019] Therefore, compared with known devices, the proposed single-pass DC-DC converter allows energy to be transferred to the load throughout the entire cycle T of the converter's operation, thereby expanding control and power capabilities. Furthermore, due to the characteristic of transferring energy to the output circuit in the form of voltage and current pulses, a time delay is created when energy is transferred to the output circuit when the regulating key 3 is turned on, thereby dispersing the increase in current and decrease in voltage through the regulating key. This significantly reduces power loss when the key is turned on, and the rectangular shape of the current flowing through the key 3 reduces losses when the key is turned off.
[0020] 1. [Polikapov AG, Sergienko EF, Single-pass converter in power supply unit for electronic equipment, Radio and Communications, 1989, p. 47] Figure 2 .1).
Claims
1. A single-ended DC-DC converter, comprising a transformer, wherein the primary winding of the transformer is connected to the input terminal of a DC voltage source via a control key, and the secondary winding is connected to the output terminal of a filter capacitor via a rectifier diode, characterized in that, In order to generate a DC output voltage from a DC input voltage and reduce dynamic power loss, the secondary winding of the transformer is connected to the terminals of the first capacitor via a series diode, and connected to the terminals of the second capacitor connected in series with the first capacitor via a second series diode removed from the transformer and not used for power input. The load is connected in parallel with the second capacitor.
2. The single-pass DC-DC converter according to claim 1, characterized in that... Transformer optimization is achieved by connecting diodes to the additional secondary winding of the transformer, thereby eliminating the transformer's non-functional quantities.