Voltage conversion circuit

Abstract

The utility model discloses a voltage conversion circuit, which comprises a first conversion module, a second conversion module and a parallel switch, and is characterized in that the first conversion module and the second conversion module receive a power supply, output direct current to electric equipment and convert the voltage of the power supply into the voltage required by the electric equipment; the first conversion module outputs a first direct current to the electric equipment, and the second conversion module outputs a second direct current to the electric equipment; the parallel switch is coupled between the second conversion module and the electric equipment and is used for switching the direct current input into the electric equipment; when the electric equipment works by using the first direct current, the efficiency of the first conversion module is greater than or equal to a first threshold value; and when the electric equipment works by using the second direct current, the efficiency of the second conversion module is greater than or equal to a second threshold value. And when the power requirements of the electric equipment are different, the conversion module is switched to meet the circuit design requirement of keeping high efficiency in a full power range.

Description

TECHNICAL FIELD

[0001] The utility model relates to power supply circuit technical field especially relates to a voltage conversion circuit. BACKGROUND

[0002] In the power supply circuit, the voltage conversion circuit needs to consider the power demand of the electrical equipment and the efficiency of the voltage conversion circuit under the power demand in the design process. The efficiency of the voltage conversion circuit is the ratio of the output power to the input power. The general power supply circuit has a higher requirement for the efficiency of the voltage conversion circuit only when it is full load, that is, when the power demand of the electrical equipment is high. When it is light load, the efficiency is not considered. With the development of new energy technology, the design scheme of the power supply circuit has higher requirements on efficiency.

[0003] In the prior art, the power supply circuit usually uses a main circuit and an auxiliary source circuit to supply power to the power consumption device and the auxiliary circuit respectively. The auxiliary circuit is generally a circuit such as a sampling circuit, a logic control circuit, a driving circuit, and an MCU circuit to ensure the normal operation of the power consumption device. The rated output power of the auxiliary source circuit is generally lower than that of the main circuit. When the power demand of the power consumption device is high, the main circuit is in full load state, and the efficiency is usually high. When the power demand of the power consumption device is low, the main circuit is in light load state, and the efficiency is low, which cannot meet the design requirement of the power supply circuit with high efficiency in the full power range. SUMMARY

[0004] The present application provides a voltage conversion circuit to solve the problem that the voltage conversion circuit in the prior art cannot maintain high efficiency in the full power range.

[0005] The present application provides a voltage conversion circuit, which includes a first conversion module, a second conversion module, and a parallel switch. The first conversion module and the second conversion module receive a power supply and output direct current to an electrical equipment, converting the voltage of the power supply to the voltage required by the electrical equipment. The first conversion module outputs first direct current to the electrical equipment, and the second conversion module outputs second direct current to the electrical equipment. The parallel switch is coupled between the second conversion module and the electrical equipment, used to switch the direct current input to the electrical equipment. When the electrical equipment works using the first direct current, the efficiency of the first conversion module is greater than or equal to a first threshold value. When the electrical equipment works using the second direct current, the efficiency of the second conversion module is greater than or equal to a second threshold value.

[0006] Further, the power utilization device comprises a main power utilization device and an auxiliary power utilization device, the auxiliary power utilization device is configured to control or drive the main power utilization device; the first conversion module comprises a high-voltage side and a low-voltage side, the high-voltage side is configured to receive the power supply, and a switch unit is arranged between a high-voltage end and a grounding end of the power supply, and is configured to control the on-off between the first conversion module and the power supply, and the low-voltage side is configured to output the first direct current to the main power utilization device; the second conversion module comprises a high-voltage side and a low-voltage side, the high-voltage side is configured to receive the power supply, the low-voltage side is configured to output the second direct current to the auxiliary power utilization device, and a parallel switch is coupled between the low-voltage side and the main power utilization device; when the parallel switch is closed, the switch unit is opened, and the second conversion module outputs the second direct current to the main power utilization device.

[0007] Further, when the input power of the main power utilization device is greater than 10% of the rated output power of the first conversion module, the parallel switch is opened, the switch unit is closed, and the efficiency of the first conversion module is greater than or equal to a first threshold value; when the input power of the main power utilization device is less than or equal to 10% of the rated output power of the first conversion module, the parallel switch is closed, the switch unit is opened, and the efficiency of the second conversion module is greater than or equal to a second threshold value.

[0008] Further, the voltage conversion circuit further comprises a detection unit coupled to the low-voltage side of the first conversion module, configured to detect the power of the first direct current and output a control signal; and a control unit configured to receive the control signal and coupled to the switch unit, and control the on-off of the switch unit.

[0009] Further, the switch unit comprises two MOS tubes connected in series between the high-voltage end and the grounding end of the power supply, and the gate ends of the two MOS tubes are coupled to the control unit; the control unit controls the on-off of the switch unit through the gate ends of the MOS tubes.

[0010] Further, the parallel switch is a relay; or, the parallel switch is a MOS tube or a triode, and is coupled to the detection unit or the control unit to keep on or off according to the control signal.

[0011] Further, the first threshold value is 92%, and the second threshold value is 90%.

[0012] Further, the rated output power of the first conversion module is greater than or equal to 300W; and the rated output power of the second conversion module is less than or equal to 100W.

[0013] Further, the rated output power of the second conversion module is less than or equal to 10% of the rated output power of the first conversion module.

[0014] Further, the first conversion module is any one of an LLC circuit, a CLLC circuit or a phase-shifted full-bridge circuit; and the second conversion module is any one of a flyback circuit, a forward circuit, a boost\buck circuit or a cuk circuit.

[0015] Through one of the above embodiments or multiple embodiments in the utility model, at least the following technical effects can be realized:

[0016] When the power demand of the electrical equipment is large, the first conversion module supplies power to the electrical equipment, so that the first conversion module is in a heavy load or full load state; when the power demand of the electrical equipment is small, i.e., in a light load state, the second conversion module supplies power to the electrical equipment through the parallel switch, so that the second conversion module is still in a heavy load or full load state, so that the voltage conversion circuit maintains high efficiency in the full power range. BRIEF DESCRIPTION OF DRAWINGS

[0017] The technical scheme and other beneficial effects of the utility model will be apparent through the following detailed description of the specific implementation manners of the utility model in combination with the drawings.

[0018] Figure 1 A module block diagram of the voltage conversion circuit of the first embodiment of the application;

[0019] Figure 2 A module block diagram of the voltage conversion circuit of the second embodiment of the application;

[0020] Figure 3 A circuit structure schematic diagram of the voltage conversion circuit of the second embodiment of the application;

[0021] Figure 4 A circuit structure schematic diagram of the voltage conversion circuit of the third embodiment of the application.

[0022] BRIEF DESCRIPTION OF DRAWINGS

[0023] 1, power supply; 2, first conversion module; 21, high-voltage side of the first conversion module 2; 22, low-voltage side of the first conversion module 2; 23, switch unit; 3, second conversion module; 31, high-voltage side of the second conversion module 3; 32, low-voltage side of the second conversion module 3; 4, parallel switch; 5, electrical equipment; 51, main electrical equipment; 52, auxiliary electrical equipment; 6, detection unit; 7, control unit. DETAILED DESCRIPTION

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0025] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the term "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Furthermore, the character " / " in this document, unless otherwise specified, generally indicates that the preceding and following related objects have an "or" relationship.

[0026] Figure 1 This is a block diagram of the voltage conversion circuit according to Embodiment 1 of this application. Figure 1 As shown, the voltage conversion circuit converts the high-voltage DC (HVDC) power supply 1 into the low-voltage DC power required by the electrical device 5. The voltage conversion circuit includes a first conversion module 2, a second conversion module 3, and a parallel switch 4. The first conversion module 2 and the second conversion module 3 are connected in parallel between the power supply 1 and the electrical device 5. The first conversion module 2 outputs a first DC power (LVDC1) to the electrical device 5, and the second conversion module 3 outputs a second DC power (LVDC2) to the electrical device 5. The parallel switch 4 is connected between the second conversion module 3 and the electrical device 5 and is used to switch the DC power input to the electrical device 5. When the electrical device 5 operates using the first DC power (LVDC1), the efficiency of the first conversion module 2 is greater than or equal to a first threshold. When the electrical device 5 operates using the second DC power (LVDC2), the efficiency of the second conversion module 3 is greater than or equal to a second threshold.

[0027] In the embodiment one, the rated output power of the first conversion module 2 is set to be greater than or equal to 300W, in the application scenario where the power demand of the electrical equipment 5 is large, when the electrical equipment 5 receives the first direct current LVDC1 output by the first conversion module 2, the first conversion module 2 is in a heavy load or full load working state, at this time the efficiency of the first conversion module 2 is greater than or equal to 92%, that is, the first threshold is 92%; the rated output power of the second conversion module 3 is set to be less than or equal to 100W, in the application scenario where the power demand of the electrical equipment 5 is small, when the electrical equipment 5 receives the second direct current LVDC2 output by the second conversion module 3, the second conversion module 3 is also in a heavy load or full load working state, at this time the efficiency of the second conversion module 3 is greater than or equal to 90%, that is, the second threshold is 90%.

[0028] Figure 2 The module block diagram of the voltage conversion circuit of the embodiment two of the present application is shown. In the embodiment two, as shown in the figure, Figure 2 the electrical equipment is a main electrical equipment 51 and an auxiliary electrical equipment 52, the auxiliary electrical equipment 52 is used to drive or control the main electrical equipment 51. The first conversion module 2 includes a high-voltage side and a low-voltage side, wherein the high-voltage side receives the power supply 1, and is provided with a switching unit 23, the switching unit 23 is used to control the on-off between the high-voltage side 21 of the first conversion module 2 and the power supply 1, and the low-voltage side 22 of the first conversion module 2 outputs the first direct current LVDC1 to the main electrical equipment 51; the second conversion module 3 also includes a high-voltage side and a low-voltage side, wherein the high-voltage side 31 of the second conversion module 3 receives the power supply 1, and the low-voltage side 32 of the second conversion module 3 outputs the second direct current LVDC2 to the auxiliary electrical equipment 52, and the parallel switch 4 is coupled between the low-voltage side 32 of the second conversion module 3 and the main electrical equipment 51; when the parallel switch 4 is closed, the switching unit 23 is opened, and the low-voltage side 32 of the second conversion module 3 outputs the second direct current LVDC2 to the main electrical equipment 51.

[0029] Figure 3The circuit structure schematic diagram of the voltage conversion circuit of the second embodiment of the present application. In the present embodiment, the high voltage side 21 of the first conversion module 2 comprises a transformer primary side, a switching unit 23, a resonant network composed of two capacitors and an inductor; the low voltage side 22 of the first conversion module 2 comprises a transformer secondary side, a synchronous rectifier composed of two diode MOS tubes, a filter network composed of a capacitor and an inductor. Among them, the switching unit 23 comprises two series-connected diode MOS tubes, the inductor in the resonant network is connected between the two diode MOS tubes, the two capacitors in the resonant network are connected in series and then connected to the two ends of the switching unit 23, one end of the transformer primary side is connected with the inductor in the resonant network, and the other end is connected between the two capacitors, forming a half-bridge circuit to convert the high-voltage direct current HVDC input by the power supply 1 into high-frequency alternating current; the low voltage side 22 of the first conversion module 2 converts the high-frequency alternating current output by the transformer secondary side into the first direct current LVDC1 through the synchronous rectifier and the filter network. The high voltage side 31 of the second conversion module 3 comprises a transformer primary side, a diode MOS tube and an RCD circuit composed of a capacitor, a resistor and a diode, which is used to absorb voltage spikes to prevent the diode MOS tube from being damaged, and the low voltage side 32 of the second conversion module 3 comprises a transformer secondary side and a rectifier filter circuit composed of a diode and a capacitor. The second direct current LVDC2 is output after the low voltage side 32 of the second conversion module 3 is rectified and filtered. In addition, a capacitor is coupled between the high voltage line of the power supply 1 and the ground line AGND1 to filter out high-frequency alternating current noise, the high voltage side 21 of the first conversion module 2 is also provided with a ground protection line PE, and a protection resistor is connected between the ground line AGND2 of the low voltage side 22 of the first conversion module 2 and the main electrical equipment 51.

[0030] In the second embodiment, as shown in Figure 3 The first conversion module 2 applies LLC circuit topology, but it should be understood that the LLC topology is only one selectable topology of the first conversion module 2, and the first conversion module 2 can also select CLLC circuit, phase-shifted full-bridge and other topologies; the second conversion module 3 applies flyback circuit topology, which is only one selectable topology of the second conversion module 3, and the second conversion module 3 can also select forward circuit, boost\buck circuit or cuk circuit and other topologies.

[0031] Figure 4 The circuit structure schematic diagram of the voltage conversion circuit of the third embodiment of the present application. The circuit structure of the third embodiment is basically the same as that of the second embodiment, as shown in Figure 4As shown, the voltage conversion circuit further comprises a detection unit 6 and a control unit 7. The detection unit 6 is coupled to the input end of the main electrical equipment 51, receives the voltage or current signal of the first direct current LVCD1, and calculates the power consumption of the main electrical equipment 51 according to the voltage or current signal and sets a preset value to determine the working state of the circuit. When the power consumption of the main electrical equipment 51, i.e. the output power of the first conversion module 2, is less than or equal to the preset value, the detection unit 6 outputs a control signal Ctrl, and the preset value is the output power of the first conversion module 2 in the light load working state. The receiving end of the control unit 7 receives the control signal Ctrl, and the output end is coupled to the gate end of two MOS tubes in the switching unit 23. The control unit 7 controls the switching unit 23 according to the control signal Ctrl, and when the power consumption of the main electrical equipment 51, i.e. the output power of the first conversion module 2, is less than or equal to the preset value, the switching unit 23 is controlled to be disconnected, and at this time the parallel switch 4 is closed, so that the second conversion module 3 outputs the second direct current LVDC2 to the main electrical equipment 51.

[0032] In embodiment three, the parallel switch 4 is a relay or a contact switch, and the high-voltage line between the second conversion module 3 and the main electrical equipment 51 is connected to the relay or the contact switch, and the input current of the main electrical equipment 51 is switched by manual control. However, it should be understood that the parallel switch 4 in the embodiment can also be selected as a MOS tube or a triode, and the MOS tube or the triode is coupled to the control signal Ctrl output end of the detection unit 6 or the output end of the control unit 7, and the MOS tube or the triode is controlled by the logic control circuit to realize the switching of the input current of the main electrical equipment 51.

[0033] In embodiment two and embodiment three, when the input power of the main electrical equipment 51 is greater than 10% of the rated output power of the first conversion module 2, the parallel switch 4 is disconnected, the switching unit 23 is closed, and the efficiency of the first conversion module 2 is greater than or equal to 92%; when the input power of the main electrical equipment 51 is less than or equal to 10% of the rated output power of the first conversion module 2, the parallel switch 4 is closed, the switching unit 23 is disconnected, and the efficiency of the second conversion module 3 is greater than or equal to 90%. In order to meet the design requirements of the above power and efficiency, i.e. when the voltage conversion circuit works in the light load state under the power demand scene of different electrical equipment, the efficiency is still kept at a high level, the rated output power of the second conversion module 3 is set to be less than or equal to 10% of the rated output power of the first conversion module 2.

[0034] In the embodiment two and the embodiment three, when the second conversion module 3 supplies power to the auxiliary power device 52 with lower power requirement, it is a low-power application scenario, and the excellent topology circuit can make the efficiency reach about 90%, when the power requirement of the main power device 51 is close to the power requirement of the auxiliary power device 52, if the first direct-current voltage conversion circuit 1 is still used to work, the first conversion module 2 is in a light load working state, and the efficiency is reduced seriously, at this time, the parallel switch 4 is closed, and the voltage conversion circuit is switched to supply power to the main power device 51 through the second conversion module 3, so that the voltage conversion circuit can meet the design requirements of high and low power requirements in the application scenarios, and keep high efficiency.

[0035] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above-mentioned division of each functional circuit and module is exemplified, and in actual application, the above-mentioned functions can be completed by different functional circuits and modules according to needs, that is, the internal structure of the device is divided into different functional circuits or modules to complete all or part of the functions described above. Each functional circuit and module in the embodiment can be integrated in one processing circuit, or each circuit can exist physically, or two or more circuits can be integrated in one circuit, and the integrated circuit can be realized in the form of hardware or software functional circuit. In addition, the specific name of each functional circuit and module is only for easy distinction, and does not limit the protection scope of the utility model. The specific working process of the circuit and module in the above system can refer to the corresponding process in the foregoing method embodiment, which will not be repeated here.

[0036] The above-described embodiments are only used to illustrate the technical solutions of the utility model, but not limit them; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the utility model, and all should be included in the protection scope of the utility model.

Claims

1. A voltage conversion circuit, characterized by, The voltage conversion circuit comprises: a first conversion module, a second conversion module and a parallel switch; the first conversion module and the second conversion module receive a power supply and output direct current to a power consumer, and convert the voltage of the power supply to the voltage required by the power consumer; the first conversion module outputs first direct current to the power consumer, and the second conversion module outputs second direct current to the power consumer; the parallel switch is coupled between the second conversion module and the power consumer, and is used to switch the direct current input to the power consumer; when the power consumer works using the first direct current, the efficiency of the first conversion module is greater than or equal to a first threshold value; when the power consumer works using the second direct current, the efficiency of the second conversion module is greater than or equal to a second threshold value.

2. The voltage conversion circuit according to claim 1, wherein: the power consumer comprises a main power consumer and an auxiliary power consumer, and the auxiliary power consumer is used to control or drive the main power consumer; the first conversion module comprises a high-voltage side and a low-voltage side, wherein the high-voltage side receives the power supply, and a switch unit is arranged between the high-voltage end and the ground end of the power supply, and is used to control the on-off between the first conversion module and the power supply, and the low-voltage side outputs the first direct current to the main power consumer; the second conversion module comprises a high-voltage side and a low-voltage side, wherein the high-voltage side receives the power supply, and the low-voltage side outputs the second direct current to the auxiliary power consumer, and the parallel switch is coupled between the low-voltage side and the main power consumer; when the parallel switch is closed, the switch unit is opened, and the second conversion module outputs the second direct current to the main power consumer.

3. The voltage conversion circuit according to claim 2, wherein: when the input power of the main power consumer is greater than 10% of the rated output power of the first conversion module, the parallel switch is opened, the switch unit is closed, and the efficiency of the first conversion module is greater than or equal to the first threshold value; when the input power of the main power consumer is less than or equal to 10% of the rated output power of the first conversion module, the parallel switch is closed, the switch unit is opened, and the efficiency of the second conversion module is greater than or equal to the second threshold value.

4. The voltage conversion circuit according to claim 2, characterized by Further comprising: a detection unit coupled to the low-voltage side of the first conversion module, detecting the power of the first direct current, and outputting a control signal; a control unit receiving the control signal and coupled to the switch unit, controlling the on-off of the switch unit.

5. The voltage conversion circuit according to claim 4, wherein: the switch unit comprises two MOS tubes connected in series between the high-voltage end and the ground end of the power supply, and the gate ends of the two MOS tubes are coupled to the control unit; the control unit controls the on-off of the switch unit through the gate end of the MOS tube.

6. The voltage conversion circuit according to claim 4, wherein: the parallel switch is a relay; or the parallel switch is a MOS tube or a triode, and is coupled to the detection unit or the control unit to keep on or off according to the control signal.

7. The voltage conversion circuit according to claim 1, wherein: The first threshold value is 92%, and the second threshold value is 90%. 8.The voltage conversion circuit of claim 1, wherein, a rated output power of the first conversion module is greater than or equal to 300W; a rated output power of the second conversion module is less than or equal to 100W. 9.The voltage conversion circuit of claim 1, wherein, the rated output power of the second conversion module is less than or equal to 10% of the rated output power of the first conversion module. 10.The voltage conversion circuit of claim 1, wherein, the first conversion module is any one of an LLC circuit, a CLLC circuit, or a phase-shifted full-bridge circuit; the second conversion module is any one of a flyback circuit, a forward circuit, a boost\buck circuit, or a cuk circuit.

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