High-frequency rectification output series-parallel dynamic thermal switching circuit
By employing a high-frequency rectified output series-parallel dynamic hot-switching circuit in the LLC resonant converter, and utilizing a switching switch to achieve series-parallel switching, the problem of high voltage withstand capability of the high-frequency rectified output capacitor is solved, extending capacitor life and reducing cost.
Patent Information
- Application Number
- CN202520131212.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-21
- Publication Date
- 2026-02-10
- Estimated Expiration
- 2035-01-21
AI Technical Summary
In LLC resonant converters, the high voltage withstand requirement of the high-frequency rectified output capacitor leads to increased cost, size, and weight. At the same time, the capacitor's lifespan is shortened and it needs to be replaced frequently, which affects the miniaturization of the equipment and maintenance costs.
A high-frequency rectified output series-parallel dynamic hot-switching circuit is adopted. By setting a switching switch between the secondary winding of the transformer and the full-bridge rectifier unit, the series-parallel switching is realized. When connected in parallel, the capacitor withstand voltage requirement is reduced, and the capacitor life is extended by the discharge circuit.
Without interrupting the output current and voltage, the voltage withstand requirement of the output capacitor is reduced, the capacitor lifespan is extended, the cost is reduced, and the miniaturization requirements of the equipment are met.
Smart Images
Figure CN223899132U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a high-frequency rectified output series-parallel dynamic hot-switching circuit, belonging to the field of switching circuit technology. Background Technology
[0002] In the field of industrial power supplies, LLC resonant converters convert input DC voltage into high-frequency AC voltage through an inverter. After rectification by a resonant network and a transformer, a stable DC voltage is obtained at the output. In LLC resonant converters, the equivalent parameters of the resonant network can be adjusted by changing the connection method of the resonant elements or circuits through series-parallel switching circuits, thereby affecting the voltage gain of the converter. Furthermore, due to the high operating frequency, a series of characteristics different from low-frequency rectification will be introduced, such as the parasitic capacitance having a more significant impact on circuit performance at high frequencies.
[0003] Therefore, in the conventional design of series-parallel switching circuits, in order to meet the voltage adaptation of different series-parallel modes, it is necessary to select output capacitors with extremely high withstand voltage values, which directly leads to a significant increase in capacitor costs. Moreover, due to the high withstand voltage requirements, the size and weight of the capacitors also increase, which becomes a serious constraint for electronic devices that pursue miniaturization and lightweight design, as well as systems with space requirements. In addition, the complex circuit conditions also cause the capacitors to be frequently subjected to high voltage stress, which greatly reduces the lifespan of the capacitors, forcing frequent capacitor replacements and further increasing the maintenance costs and downtime frequency of the equipment. Utility Model Content
[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-frequency rectifier output series-parallel dynamic hot-switching circuit, which can realize the series-parallel switching of the output circuit without interrupting the output current and voltage, while reducing the voltage withstand requirement of the output capacitor, improving the capacitor life and reducing costs.
[0005] To solve the above-mentioned technical problems, this utility model is implemented using the following technical solution:
[0006] In a first aspect, this utility model provides a high-frequency rectified output series-parallel dynamic hot-switching circuit, including a transformer, a full-bridge rectifier unit, and a switching switch. It includes at least two sets of transformers, each set having one primary winding and at least two secondary windings. The number of full-bridge rectifier units is the same as the number of secondary windings in each set of transformers, and the secondary windings in each set of transformers are independent of each other. Each secondary winding is electrically connected to each full-bridge rectifier unit, and a switching switch is provided between at least one secondary winding in each set of transformers and the full-bridge rectifier unit. The full-bridge rectifier units are electrically connected through the switching switch to achieve series-parallel switching between them. Each full-bridge rectifier unit is connected in parallel to a capacitor branch, and at least one capacitor branch is connected in parallel to a bleeder resistor branch. A switching switch is provided on the bleeder resistor branch.
[0007] In conjunction with the first aspect, optionally, the transformer includes a first transformer and a second transformer. The first transformer includes a primary winding NP1, a first secondary winding NS1, and a second secondary winding NS2. The second transformer includes a primary winding NP2, a third secondary winding NS3, and a fourth secondary winding NS4. The full-bridge rectifier unit includes a first full-bridge rectifier unit and a second full-bridge rectifier unit.
[0008] In conjunction with the first aspect, optionally, the first full-bridge rectifier unit includes diodes D1, D2, D3, and D4, wherein diodes D1 and D2 are connected in series to form a first series branch, and diodes D3 and D4 are connected in series to form a second series branch, and the first series branch and the second series branch are connected in parallel; the second full-bridge rectifier unit includes diodes D5, D6, D7, and D8, wherein diodes D5 and D6 are connected in series to form a third series branch, and diodes D7 and D8 are connected in series to form a fourth series branch, and the third series branch and the fourth series branch are connected in parallel.
[0009] In conjunction with the first aspect, optionally, a switching switch S1 is connected in series between the same-name terminal of the first secondary winding NS1 and diodes D1 and D2, and the opposite-name terminal of the first secondary winding NS1 is electrically connected between diodes D3 and D4; the opposite-name terminal of the second secondary winding NS2 is electrically connected between diodes D5 and D6, and the same-name terminal of the second secondary winding NS2 is electrically connected between diodes D7 and D8; a switching switch S2 is connected in series between the same-name terminal of the third secondary winding NS3 and diodes D1 and D2, and the opposite-name terminal of the third secondary winding NS3 is electrically connected between diodes D3 and D4; the opposite-name terminal of the fourth secondary winding NS4 is electrically connected between diodes D5 and D6, and the same-name terminal of the fourth secondary winding NS4 is electrically connected between diodes D7 and D8.
[0010] In conjunction with the first aspect, optionally, the first full-bridge rectifier unit is connected in parallel with capacitor C1, and the second full-bridge rectifier unit is connected in parallel with capacitor C2. Capacitor C1 is connected in parallel with a bleeder resistor branch, which includes a resistor R1 connected in series and a switching switch S6. One end of capacitor C1 is connected to the positive terminal of diode D9, and the negative terminal of diode D9 is the output terminal A1. The other end of capacitor C2 is the output terminal A2, and one end of capacitor C2 is the output terminal B1. The other end of capacitor C2 is the output terminal B2. A switching switch S3 is connected in series between output terminals A1 and B1, a switching switch S4 is connected in series between output terminals A2 and B2, and a switching switch S5 is connected in series between output terminals A2 and B1.
[0011] In conjunction with the first aspect, optionally, the switching switch is at least one of a MOSFET and an IGBT.
[0012] In conjunction with the first aspect, optionally, the primary circuit of the transformer is one of the following: a phase-shifted full-bridge topology, a phase-shifted half-bridge topology, a single-phase LLC full-bridge topology, or a single-phase LLC half-bridge topology.
[0013] Compared with the prior art, the beneficial effects achieved by this utility model are as follows:
[0014] This invention provides switching switches at the secondary windings of each transformer and at the connection points of each full-bridge rectifier unit. The switching switches enable series-parallel switching between the secondary windings and the full-bridge rectifier units. Simultaneously, through the discharge circuit and the switching switches, the voltage withstand requirement of the output capacitor is reduced without interrupting the output current and voltage, thereby indirectly improving the capacitor's lifespan and reducing costs. Attached Figure Description
[0015] Figure 1 This is a circuit diagram of a high-frequency rectified output series-parallel dynamic hot-switching circuit according to an embodiment of this utility model. Detailed Implementation
[0016] The technical solution of this utility model will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments and specific features in the embodiments are detailed descriptions of the technical solution of this application, rather than limitations thereof.
[0017] In the description of this utility model, the terms "first" and "second" are used only to distinguish technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features or the order of the technical features.
[0018] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0019] Example 1:
[0020] like Figure 1 As shown, this utility model provides a high-frequency rectified output series-parallel dynamic hot-switching circuit, including a transformer, a full-bridge rectifier unit, and a switching switch. In some embodiments, the switching switch is at least one of a MOSFET and an IGBT; it includes at least two sets of transformers, each set of transformers having one primary winding and at least two secondary windings. The number of full-bridge rectifier units is the same as the number of secondary windings in each set of transformers. In one embodiment, such as... Figure 1 As shown, the transformer includes a first transformer and a second transformer. In some embodiments, the first transformer is a positive transformer and the second transformer is a negative transformer. The first transformer includes a primary winding NP1, a first secondary winding NS1, and a second secondary winding NS2. The second transformer includes a primary winding NP2, a third secondary winding NS3, and a fourth secondary winding NS4. The full-bridge rectifier unit includes a first full-bridge rectifier unit and a second full-bridge rectifier unit.
[0021] The secondary windings in each group of transformers are independent of each other, and each secondary winding is electrically connected to each full-bridge rectifier unit. At least one secondary winding in each group of transformers is connected to a switching switch between the full-bridge rectifier unit and the full-bridge rectifier unit. The full-bridge rectifier units are electrically connected through the switching switches to realize the series-parallel switching between the full-bridge rectifier units. Each full-bridge rectifier unit is connected in parallel with a capacitor branch, and at least one capacitor branch is connected in parallel with a discharge resistor branch. A switching switch is provided on the discharge resistor branch.
[0022] In some embodiments, the first full-bridge rectifier unit includes diodes D1, D2, D3, and D4. Diodes D1 and D2 are connected in series to form a first series branch, and diodes D3 and D4 are connected in series to form a second series branch. The first series branch and the second series branch are connected in parallel. The second full-bridge rectifier unit includes diodes D5, D6, D7, and D8. Diodes D5 and D6 are connected in series to form a third series branch, and diodes D7 and D8 are connected in series to form a fourth series branch. The third series branch and the fourth series branch are connected in parallel.
[0023] A switch S1 is connected in series between the same-name terminal of the first secondary winding NS1 and diodes D1 and D2, and the opposite-name terminal of the first secondary winding NS1 is electrically connected between diodes D3 and D4; the opposite-name terminal of the second secondary winding NS2 is electrically connected between diodes D5 and D6, and the same-name terminal of the second secondary winding NS2 is electrically connected between diodes D7 and D8; a switch S2 is connected in series between the same-name terminal of the third secondary winding NS3 and diodes D1 and D2, and the opposite-name terminal of the third secondary winding NS3 is electrically connected between diodes D3 and D4; the opposite-name terminal of the fourth secondary winding NS4 is electrically connected between diodes D5 and D6, and the same-name terminal of the fourth secondary winding NS4 is electrically connected between diodes D7 and D8.
[0024] A capacitor C1 is connected in parallel to the first full-bridge rectifier unit, and a capacitor C2 is connected in parallel to the second full-bridge rectifier unit. Capacitor C1 is connected in parallel with a bleeder resistor branch, which includes a resistor R1 connected in series and a switch S6. Capacitor C1, resistor R1, and switch S6 constitute a bleeder circuit. When switch S6 is closed, the bleeder circuit operates; when switch S6 is open, the bleeder circuit stops operating. One end of capacitor C1 is connected to the anode of diode D9, and the cathode of diode D9 is the output terminal A1. The other end of capacitor C2 is the output terminal A2. One end of capacitor C2 is output terminal B1, and the other end of capacitor C2 is output terminal B2; a switch S3 is connected in series between output terminals A1 and B1, a switch S4 is connected in series between output terminals A2 and B2, and a switch S5 is connected in series between output terminals A2 and B1; the positive terminal of output port A is output terminal A1, and the negative terminal of output port A is output terminal A2; the positive terminal of output port B is output terminal B1, and the negative terminal of output port B is output terminal B2; the positive terminal of the whole machine's output terminal is output port A1, and the negative terminal of the whole machine's output terminal is output port B2.
[0025] In some embodiments, the primary circuit of the transformer is one of a phase-shifted full-bridge topology, a phase-shifted half-bridge topology, a single-phase LLC full-bridge topology, or a single-phase LLC half-bridge topology.
[0026] Example 2:
[0027] This utility model provides a method for dynamic hot-switching of series and parallel high-frequency rectified outputs, using the dynamic hot-switching circuit for series and parallel high-frequency rectified outputs as described in Embodiment 1. The method includes:
[0028] Measure the voltage from output port A1 to output port A2, which is the voltage at output port A.
[0029] Measure the voltage from output port B1 to output port B2, which is the voltage at output port B.
[0030] Measure the voltage from output port A1 to output port B2; this is the total output voltage of the device.
[0031] Based on the circuit connection status, determine the relationship between the overall output voltage and the preset switching value;
[0032] Based on the judgment result, control the on / off state of each switching switch.
[0033] When the circuit is in parallel operation, switches S1, S2, S3, and S4 are closed, while switches S5 and S6 are open. Output ports A1 and B1 are short-circuited, and output ports A2 and B2 are short-circuited, meaning output ports A and B are connected in parallel. The circuit then checks if the overall output voltage exceeds a first preset switching value. In some embodiments, this first preset switching value is half the maximum output voltage plus a bias voltage. The specific value of the bias voltage depends on the gain curve of the resonant circuit; in one embodiment, the bias voltage is 10V. If the overall output voltage exceeds the first preset switching value, the parallel-to-series switching logic is activated.
[0034] The parallel-to-serial switching logic includes:
[0035] Simultaneously disconnect switch S1, switch S2, and switch S4;
[0036] The switching switch S6 is engaged to discharge the output capacitor C1. After the discharge is completed, the switching switch S6 is disengaged. In some embodiments, the method to determine whether the discharge of capacitor C1 is completed is to determine whether the voltage at the output port A is lower than a preset voltage. In one embodiment, the preset voltage is 10V.
[0037] Engagement switch S5, disengagement switch S3;
[0038] Simultaneously, switch S1 and switch S2 are activated, thus switching to the series operation state.
[0039] When the circuit is in series operation, switches S1 and S2 are closed, switches S3, S4, and S6 are open, and switch S5 is closed. At this time, output port A2 and output port B1 are short-circuited, meaning output port A and output port B are connected in series. Then, it is determined whether the overall output voltage is greater than the second preset switching value. In some embodiments, the second preset switching value is half the maximum output voltage minus the bias voltage. The specific value of the bias voltage depends on the gain curve of the resonant circuit; in one embodiment, the bias voltage is 10V. Next, it is determined whether the overall output voltage is less than the second preset switching value. If so, the series-to-parallel switching logic is activated.
[0040] The serial-to-parallel switching logic includes:
[0041] At the same time, switch S1 and switch S2 are pulled open. At this time, the voltage across capacitor C1 discharges through the output load. As the voltage of capacitor C1 gradually drops, the voltage of capacitor C2 gradually rises, keeping the overall output voltage of the machine constant.
[0042] When capacitor C1 gradually drops to zero, switch S3 is engaged and switch S5 is disengaged. At this time, output port B outputs only, and output port A has no energy output. In some embodiments, the voltage at output port A is used to determine whether capacitor C1 has dropped to zero. When the voltage at output port A is lower than the preset voltage, it is determined that capacitor C1 has dropped to zero.
[0043] When the switch S5 is engaged, output port A and output port B are connected in parallel. At the same time, due to the presence of the reverse connection protection diode D9, there will be no inrush current.
[0044] Simultaneously, switching switches S1 and S2 are activated, and output ports A and B output energy at the same time, thus switching to parallel operation mode.
[0045] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.
Claims
1. A high-frequency rectified output series-parallel dynamic hot-switching circuit, comprising a transformer, a full-bridge rectifier unit, and a switching switch, characterized in that: The system includes at least two sets of transformers, each set having one primary winding and at least two secondary windings. The number of full-bridge rectifier units is the same as the number of secondary windings in each set of transformers, and the secondary windings in each set of transformers are independent of each other. Each secondary winding is electrically connected to each full-bridge rectifier unit, and a switching switch is provided between at least one secondary winding and each full-bridge rectifier unit in each set of transformers. The full-bridge rectifier units are electrically connected to each other through the switching switches to achieve series-parallel switching between the full-bridge rectifier units. Each full-bridge rectifier unit is connected in parallel with a capacitor branch, and at least one capacitor branch is connected in parallel with a bleeder resistor branch, with a switching switch provided on the bleeder resistor branch.
2. The high-frequency rectified output series-parallel dynamic hot-switching circuit according to claim 1, characterized in that: The transformer includes a first transformer and a second transformer. The first transformer includes a primary winding NP1, a first secondary winding NS1 and a second secondary winding NS2. The second transformer includes a primary winding NP2, a third secondary winding NS3 and a fourth secondary winding NS4. The full-bridge rectifier unit includes a first full-bridge rectifier unit and a second full-bridge rectifier unit.
3. The high-frequency rectified output series-parallel dynamic hot-switching circuit according to claim 2, characterized in that: The first full-bridge rectifier unit includes diodes D1, D2, D3, and D4. Diodes D1 and D2 are connected in series to form a first series branch, and diodes D3 and D4 are connected in series to form a second series branch. The first series branch and the second series branch are connected in parallel. The second full-bridge rectifier unit includes diodes D5, D6, D7, and D8. Diodes D5 and D6 are connected in series to form a third series branch, and diodes D7 and D8 are connected in series to form a fourth series branch. The third series branch and the fourth series branch are connected in parallel.
4. The high-frequency rectified output series-parallel dynamic hot-switching circuit according to claim 3, characterized in that: A switching switch S1 is connected in series between the same-name terminal of the first secondary winding NS1 and diodes D1 and D2, and the opposite-name terminal of the first secondary winding NS1 is electrically connected between diodes D3 and D4; the opposite-name terminal of the second secondary winding NS2 is electrically connected between diodes D5 and D6, and the same-name terminal of the second secondary winding NS2 is electrically connected between diodes D7 and D8; a switching switch S2 is connected in series between the same-name terminal of the third secondary winding NS3 and diodes D1 and D2, and the opposite-name terminal of the third secondary winding NS3 is electrically connected between diodes D3 and D4; the opposite-name terminal of the fourth secondary winding NS4 is electrically connected between diodes D5 and D6, and the same-name terminal of the fourth secondary winding NS4 is electrically connected between diodes D7 and D8.
5. The high-frequency rectified output series-parallel dynamic hot-switching circuit according to claim 2 or 4, characterized in that: The first full-bridge rectifier unit has a capacitor C1 connected in parallel, and the second full-bridge rectifier unit has a capacitor C2 connected in parallel. The capacitor C1 is connected in parallel with a bleeder resistor branch, which includes a resistor R1 connected in series and a switching switch S6. One end of the capacitor C1 is connected to the positive terminal of the diode D9, and the negative terminal of the diode D9 is the output terminal A1. The other end of the capacitor C2 is the output terminal A2, and one end of the capacitor C2 is the output terminal B1. The other end of the capacitor C2 is the output terminal B2. A switching switch S3 is connected in series between the output terminals A1 and B1, a switching switch S4 is connected in series between the output terminals A2 and B2, and a switching switch S5 is connected in series between the output terminals A2 and B1.
6. The high-frequency rectified output series-parallel dynamic hot-switching circuit according to claim 1, characterized in that: The switching switch is at least one of a MOSFET and an IGBT.
7. The high-frequency rectified output series-parallel dynamic hot-switching circuit according to claim 1, characterized in that: The primary circuit of the transformer is one of the following: phase-shifted full-bridge topology, phase-shifted half-bridge topology, single-phase LLC full-bridge topology, and single-phase LLC half-bridge topology.