CN212627721U

CN212627721U - Linear power supply

Info

Publication number: CN212627721U
Application number: CN202021545596.0U
Authority: CN
Inventors: 陈人杰; 毕宝云; 马锋
Original assignee: Schneider Electric China Co Ltd
Current assignee: Schneider Electric China Co Ltd
Priority date: 2020-07-30
Filing date: 2020-07-30
Publication date: 2021-02-26
Anticipated expiration: 2030-07-30

Abstract

The utility model relates to a linear power supply, include: a rectifying unit for converting an alternating current voltage input from a three-phase power supply into a rectified voltage; the voltage transformation unit is connected to the rectifying unit and used for adjusting the rectified voltage output by the rectifying unit, wherein the voltage transformation unit comprises a voltage reduction transistor switch and a control transistor switch; the voltage reduction transistor switch is connected between the output end of the rectification unit and the output end of the voltage transformation unit and is used for bearing the voltage difference between the output end of the rectification unit and the output end of the voltage transformation unit; and the control transistor switch is connected between the control end of the step-down transistor and the output end of the voltage transformation unit, and the control end of the control transistor switch is controlled by the rectified voltage output by the rectification unit, so that the step-down transistor switch is controlled to be turned off when the rectified voltage output by the rectification unit is greater than a threshold value.

Description

Linear power supply

Technical Field

The utility model relates to a power especially relates to three-phase linear power supply.

Background

The linear power supply based on the semiconductor switches such as the transistors has the characteristics of low cost, small volume, simple design, wide input voltage range, stability, reliability and the like, and is widely used in various electrical equipment with low-power loads. However, such a linear power supply has the disadvantages of low power efficiency, severe heat generation, etc., so many electrical appliances have to select a switching power supply, which results in a large size and high cost of the product. Compared with the two power supplies, a novel power supply which has both power supply efficiency and cost needs to be developed.

SUMMERY OF THE UTILITY MODEL

The utility model provides a can be according to the high efficiency three-phase linear power supply of electric wire netting frequency self-adaptation switch, it can reduce whole average power consumption, extends the application scope of linear power supply to can also reach the purpose of low cost, miniaturization, wide input range, high reliability.

According to the utility model discloses an embodiment provides a linear power supply, include: a rectifying unit for converting an alternating current voltage input from a three-phase power supply into a rectified voltage; the voltage transformation unit is connected to the rectifying unit and used for adjusting the rectified voltage output by the rectifying unit, wherein the voltage transformation unit comprises a voltage reduction transistor switch and a control transistor switch; the voltage reduction transistor switch is connected between the output end of the rectification unit and the output end of the voltage transformation unit and is used for bearing the voltage difference between the output end of the rectification unit and the output end of the voltage transformation unit; and the control transistor switch is connected between the control end of the voltage reduction transistor switch and the output end of the voltage transformation unit, and the control end of the control transistor switch is controlled by the rectified voltage output by the rectification unit, so that the voltage reduction transistor switch is controlled to be turned off when the rectified voltage output by the rectification unit is greater than a threshold value.

Optionally, the voltage transformation unit further includes a first resistor, a first voltage regulation tube module, a second resistor, a second voltage regulation tube module, and a third resistor; a first end of the buck transistor switch is connected to an output end of the rectifying unit, a second end of the buck transistor switch is connected to an output end of the transforming unit, and a control end of the buck transistor switch is connected to the first end of the buck transistor switch through the first resistor; a first end of the first resistor is connected to a first end of the buck transistor switch, and a second end of the first resistor is connected to a control end of the buck transistor switch; the first end of the first voltage-stabilizing tube module is connected to the second end of the first resistor, the second end of the first voltage-stabilizing tube module is connected to the ground end, and the first end of the first voltage-stabilizing tube module is the voltage-stabilizing end of the first voltage-stabilizing tube module; a first end of the control transistor switch is connected to a control end of the buck transistor switch, a second end of the control transistor switch is connected to a second end of the buck transistor switch, and the control end of the control transistor switch is connected to an output end of the rectifying unit through the second voltage stabilizing tube module and the third resistor; the first end of the second voltage-stabilizing tube module is connected to the second end of the third resistor, the second end of the second voltage-stabilizing tube module is connected to the control end of the control transistor switch, the first end of the third resistor is connected to the output end of the rectifying unit, and the first end of the second voltage-stabilizing tube module is the voltage-stabilizing end of the second voltage-stabilizing tube module; and a first terminal of the second resistor is connected to the control terminal of the control transistor switch and a second terminal of the second resistor is connected to the second terminal of the control transistor switch.

Optionally, the rectifying unit includes a first diode, a second diode, a third diode, and a fourth diode; the anode of the first diode is connected to a first phase line of the three-phase power supply, and the cathode of the first diode is connected to the output end of the rectifying unit; the anode of the second diode is connected to a second phase line of the three-phase power supply, and the cathode of the second diode is connected to the output end of the rectifying unit; the cathode of the third diode is connected to a third phase line of the three-phase power supply, and the anode of the third diode is connected to a ground terminal; and a cathode of the fourth diode is connected to a neutral line of the three-phase power supply, and an anode of the fourth diode is connected to a ground terminal.

Optionally, the rectifying unit further includes a fifth diode and a sixth diode; the cathode of the fifth diode is connected to the second phase line of the three-phase power supply, and the anode of the fifth diode is connected to the ground terminal; and an anode of the sixth diode is connected to a neutral line of the three-phase power supply, and a cathode of the sixth diode is connected to an output terminal of the rectification unit.

Optionally, the voltage transformation unit further includes a start transistor switch, and the start transistor switch is connected between the second end of the buck transistor switch and the second end of the control transistor switch.

Optionally, the voltage transformation unit further includes a fourth resistor, a third voltage regulation tube module, and a fifth resistor; the first end of the starting transistor switch is connected to the second end of the buck transistor switch, the second end of the starting transistor switch is connected to the second end of the control transistor switch, and the control end of the starting transistor switch is connected to the ground end through the fourth resistor and the third voltage stabilizing tube module; the first end of the fourth resistor is connected to the control end of the starting transistor switch, the second end of the fourth resistor is connected to the first end of the third voltage-stabilizing tube module, the second end of the third voltage-stabilizing tube module is connected to the ground end, and the first end of the third voltage-stabilizing tube module is the voltage-stabilizing end of the third voltage-stabilizing tube module; and a first terminal of the fifth resistor is connected to the control terminal of the start transistor switch and a second terminal of the fifth resistor is connected to the second terminal of the start transistor switch.

Optionally, the transformation unit further includes a capacitor module, and the capacitor module includes one or more capacitors connected between the output terminal and the ground terminal of the transformation unit.

Optionally, the linear power supply further includes a dc-dc converter, and the dc-dc converter is connected to the output end of the voltage transformation unit.

Optionally, the step-down transistor switch is an IGBT, a control end of the step-down transistor switch is a gate of the IGBT, a first end of the step-down transistor switch is a collector of the IGBT, and a second end of the step-down transistor switch is an emitter of the IGBT.

Optionally, the control transistor switch is an NPN-type triode, a control end of the control transistor switch is a base of the NPN-type triode, a first end of the control transistor switch is a collector of the NPN-type triode, and a second end of the control transistor switch is an emitter of the NPN-type triode.

Optionally, the starting transistor switch is a PNP type triode, the control end of the starting transistor switch is a base electrode of the PNP type triode, the first end of the control transistor switch is a collector electrode of the PNP type triode, and the second end of the control transistor switch is an emitter electrode of the PNP type triode.

Drawings

These and/or other aspects, features and advantages of the present invention will become more apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 shows a block diagram of a circuit configuration of a linear power supply according to an embodiment of the present invention.

Fig. 2 shows a schematic circuit diagram of a voltage transformation unit according to an embodiment of the present invention.

Fig. 3 shows a schematic circuit diagram of a voltage transformation unit according to another embodiment of the present invention.

Fig. 4 shows a schematic circuit diagram of a rectifying unit according to an embodiment of the present invention.

Fig. 5 shows a schematic circuit diagram of a rectifying unit according to another embodiment of the present invention.

Fig. 6 shows a schematic circuit diagram of a rectifying unit according to another embodiment of the present invention.

Fig. 7 shows a schematic diagram of a rectified output according to an embodiment of the invention.

Fig. 8 shows a schematic circuit diagram of a linear power supply according to an embodiment of the present invention.

Fig. 9A-9B show schematic performance graphs of a linear power supply according to an embodiment of the invention.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings so that those skilled in the art can easily practice the present disclosure. However, the present invention is not limited to the embodiments described herein, which may be embodied in various different forms. The described embodiments are intended only to be exhaustive and complete, and to fully convey the concept of the invention to those skilled in the art. Features of the various embodiments described may be combined with each other or substituted for each other unless expressly excluded or otherwise excluded in context. Moreover, in the drawings and throughout the specification, like/similar reference numerals designate like elements.

In the embodiments of the present invention, unless otherwise specifically stated, "connected" does not mean that "directly connected" or "directly in contact" is necessary, but only needs to be electrically connected. Furthermore, the terms "first," "second," and the like, herein are used solely to distinguish one element from another, and do not denote any order or priority, nor do they denote whether values of parameters for two elements are the same or different.

The utility model discloses an optimize linear step-down circuit topological structure for this linear step-down circuit topological structure turn-offs when high pressure differential, switches on when low pressure differential, thereby realizes the switching characteristic who suits with the electric wire netting frequency. And moreover, by the optimized design of the three-phase rectifier bridge, the three-phase rectification output voltage can be matched with the linear voltage reduction circuit topological structure of the power frequency switch. Therefore, the utility model discloses can provide a high efficiency three-phase linear power according to electric wire netting frequency self-adaptation switch, it can reduce whole average power consumption, extends linear power's application scope to can also reach low cost, miniaturized, wide input range, high reliability's purpose

Referring to fig. 1, a linear power supply 100 according to an embodiment of the present invention receives an ac voltage input from a three-phase power supply. For example, a three-phase power supply may consist of three alternating potentials (three phase lines A, B, C) of the same frequency, of equal amplitude, and sequentially 120 ° out of phase with each other, and may also include a neutral line N, i.e. the non-inverting terminal of the three phase lines.

According to the embodiment of the present invention, the linear power supply 100 may include a port protection module 101, a rectification unit 102, a voltage transformation unit 103, and a dc-dc converter 104.

As shown in fig. 1, the port protection module 101 is connected between the output terminals (A, B, C and N) of the three-phase power source and the input terminal of the rectification unit 102, and is used for limiting the voltage or current on each phase line to protect the three-phase power source to meet the related electromagnetic Compatibility (EMC) standard. The port guard module 101 may employ any existing port guard.

The rectifying unit 102 is connected between the port protection module 101 and the transforming unit 103, and is configured to convert an ac voltage input from a three-phase power supply into a rectified voltage (denoted as VA) and output the rectified voltage to the transforming unit 103.

The transforming unit 103 is connected to an output terminal of the rectifying unit 102, and is configured to adjust a rectified Voltage (VA) output from the rectifying unit 102, for example, to lower the rectified voltage from a higher value (e.g., about several hundred volts) to a desired lower value (e.g., about several tens of volts) so as to be supplied to a load.

The dc-dc converter 104 is connected to the output terminal of the transforming unit 103 for further reducing the voltage (denoted as VDD) output by the transforming unit 103 to a voltage (denoted as VCC) suitable for a specific certain load, for example, in one embodiment, the dc-dc converter 104 may be a BUCK circuit.

It should be noted that, in the linear power supply 100 according to the embodiment of the present invention, the port protection module 101 and the dc-dc converter 104 are optional, that is, the linear power supply 100 may not include the port protection module 101 and/or the dc-dc converter 104.

Fig. 2 shows a schematic circuit diagram of the voltage transforming unit 203 according to an embodiment of the present invention. The transforming unit 203 may be used as the transforming unit 103 in fig. 1.

The transforming unit 203 includes a step-down transistor switch T1 and a control transistor switch T2.

The buck transistor switch T1 is connected between the output terminal of the rectifying unit 102 and the output terminal of the transforming unit 203, and is used for carrying a voltage difference between the output terminal of the rectifying unit 102 and the output terminal of the transforming unit 203. In one embodiment, the buck Transistor switch T1 may be an Insulated Gate Bipolar Transistor (IGBT). In one embodiment, the buck Transistor switch T1 may be a Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET).

The control transistor switch T2 is connected between the control terminal of the buck transistor switch T1 and the output terminal of the transforming unit 203, and the control terminal of the control transistor switch T2 is controlled by the rectified voltage VA output by the rectifying unit 102, so that the buck transistor switch T1 is controlled to turn off when the rectified voltage VA output by the rectifying unit 102 is greater than a set threshold. In one embodiment, the control transistor switch T2 may be a transistor, such as an NPN transistor.

The following description is given by taking as an example an embodiment in which the step-down transistor switch T1 is an IGBT and the control transistor switch T2 is an NPN transistor, and it is obvious to those skilled in the art that other similar transistor switches can be adopted to implement the embodiments of the present invention.

According to the utility model discloses vary voltage unit 203 can turn off step-down transistor switch T1 when step-down transistor switch T1 both ends high-pressure differential through control transistor switch T2, and turn on step-down transistor switch T1 when step-down transistor switch T1 both ends low-pressure differential for energy transmits high-efficiently, thereby realizes low-cost, miniaturization, wide input range.

Specifically, in one embodiment, referring to fig. 2, the transforming unit 203 further includes a first resistor R1, a first voltage regulation pipe module Z1, a second resistor R2, a second voltage regulation pipe module Z2, and a third resistor R3.

A first terminal (e.g., a collector c of the IGBT) of the step-down transistor switch T1 is connected to the output terminal of the rectifying unit 102, a second terminal (e.g., an emitter e of the IGBT) of the step-down transistor switch T1 is connected to the output terminal of the transforming unit 203, and a control terminal (e.g., a gate g of the IGBT) of the step-down transistor switch T1 is connected to a first terminal of the step-down transistor switch T1 through a first resistor R1. A first terminal of the first resistor R1 is connected to a first terminal of the buck transistor switch T1, and a second terminal of the first resistor R1 is connected to a control terminal of the buck transistor switch T1. The first terminal of the first zener diode module Z1 is connected to the second terminal of the first resistor R1, the second terminal of the first zener diode module Z1 is connected to ground, the first zener diode module Z1 may include one or more zener diodes ZD1 connected in series, and the first terminal of the first zener diode module Z1 is its zener terminal, i.e., the terminal corresponding to the cathode of the zener diode. A first terminal (e.g., a collector c of the NPN transistor) of the control transistor switch T2 is connected to the control terminal of the buck transistor switch T1, a second terminal (e.g., an emitter e of the NPN transistor) of the control transistor switch T2 is connected to the second terminal of the buck transistor switch T1, and a control terminal (e.g., a base b of the NPN transistor) of the control transistor switch T2 is connected to the output terminal of the rectification unit through the second zener diode module Z2 and the third resistor R3. The first end of the second zener diode module Z2 is connected to the second end of the third resistor R3, the second end of the second zener diode module Z2 is connected to the control end of the control transistor switch T2, the first end of the third resistor R3 is connected to the output end of the rectifying unit, the second zener diode module Z2 may include one or more zener diodes ZD2, ZD3 connected in series, and the first end of the second zener diode module Z2 is its zener end, i.e., the end corresponding to the cathode of the zener diode. A first terminal of the second resistor R2 is connected to the control terminal of the control transistor switch T2, and a second terminal of the second resistor R2 is connected to the second terminal of the control transistor switch T2.

According to the embodiment of the present invention, as shown in fig. 2, when T2 is turned on, the voltage between the collector of T2 and the emitter of T2 is very low, i.e., the voltage between the gate of T1 and the emitter of T1 is very low, so that T1 is turned off; when T2 is turned off, a voltage difference is obtained between the gate of T1 and the emitter of T1, so that T1 is turned on.

The control terminal voltage of the control transistor switch T2 is controlled by the rectified voltage VA and the regulator block Z2, in other words, the on-off state of the control transistor switch T2 is associated with the variation of the rectified voltage VA and the parameters of the regulator block Z2. Therefore, the set threshold of the rectified voltage VA as described above can be set by appropriately configuring the zener module Z2 such that the control transistor switch T2 controls the buck transistor switch T1 to turn off when the rectified voltage VA is greater than or equal to the set threshold, and the control transistor switch T2 controls the buck transistor switch T1 to turn on when the rectified voltage VA is less than the set threshold. In addition, the magnitude of the output voltage VDD is mainly determined by configuring the first regulator tube module Z1.

In one embodiment, the transforming unit 203 further includes a capacitor module 2031. For example, the capacitor module 2031 may include one or more capacitors connected between the output terminal of the transforming unit 203 and the ground terminal, such as C1, C2, and C3 connected in parallel. The capacitor module 2031 is used to filter the output voltage VDD and buffer voltage variations in the circuit. For example, as the transistor switch T1 is also periodically switched due to the periodic variation of VA, the charging and discharging of the capacitor module 2031 stabilizes the output voltage.

Fig. 3 shows a schematic circuit diagram of the voltage transforming unit 303 according to another embodiment of the present invention.

The transforming unit 303 of fig. 3 is a modification of the transforming unit 203 of fig. 2. As shown in fig. 3, the transforming unit 303 further comprises a start transistor switch T3. The enabling transistor switch T3 is connected between the second terminal of the buck transistor switch T1 and the second terminal of the control transistor switch T2 for ensuring that the circuit can be enabled for fast start-up, in other words, to enable the buck transistor switch to turn on quickly at power-up. When the transforming unit 303 is powered on, the enabling transistor switch T3 is turned off first, so that the dropping transistor switch T1 can be turned on even if the controlling transistor switch T2 is turned on, i.e., the dropping transistor switch T1 is turned on. In one embodiment, the enabling transistor switch T3 may be a transistor, such as a PNP transistor.

The following description will be made by taking an example in which the start transistor switch T3 is a PNP type transistor.

Specifically, in one embodiment, the transforming unit 303 further includes a fourth resistor R4, a third zener diode module Z3, and a fifth resistor R5.

A first terminal (e.g., a collector c of the PNP transistor) of the enabling transistor switch T3 is connected to the second terminal of the buck transistor switch T1, a second terminal (e.g., an emitter e of the PNP transistor) of the enabling transistor switch T3 is connected to the second terminal of the control transistor switch T2, and a control terminal (e.g., a base b of the PNP transistor) of the enabling transistor switch T3 is connected to the ground terminal through the fourth resistor R4 and the third zener diode module Z3. A first terminal of the fourth resistor R4 is connected to the control terminal of the enabling transistor switch T3, a second terminal of the fourth resistor R4 is connected to a first terminal of the third zener diode module Z3, a second terminal of the third zener diode module Z3 is connected to the ground terminal, the third zener diode module Z3 may include one or more zener diodes ZD4, and the first terminal of the third zener diode module Z3 is its zener terminal, i.e., the terminal corresponding to the cathode of the zener diode. A first terminal of the fifth resistor R5 is connected to the control terminal of the enabling transistor switch T3, and a second terminal of the fifth resistor R5 is connected to the second terminal of the enabling transistor switch T3.

According to the embodiment of the present invention, in the case where the start transistor switch T3 is not provided, that is, in the voltage transforming unit 203 shown in fig. 2, when power is turned on, VA instantaneously raises the high voltage to turn on the control transistor switch T2, so that the step-down transistor T1 is turned off. As shown in fig. 3, in the transforming unit 303 provided with the start transistor switch T3, when power is applied, VA rises instantaneously to a high voltage to turn on the control transistor switch T2. However, before the pull-down transistor T1 is turned on, the output voltage VDD is zero, the gate voltage of T1 is low, and the emitter voltage of T3 is low. The very low emitter voltage of T3 cannot break down the third zener module Z3 to form a current, and thus cannot turn on T3. When T2 is turned on and T3 is turned off, the voltage between the gate of T1 and the emitter of T1 is not clamped to a low voltage by the turn-on of T2, so that T1 can be turned on more quickly to enter an operating state to transmit a voltage.

Therefore, by providing the start transistor switch T3, the transforming unit 303 can start up more quickly at power up. After the transformer unit 303 is started, the emitter voltage of the start transistor switch T3 rises quickly to keep it in a conducting state, and does not affect the control of the buck transistor switch T1 by the control transistor switch T2.

Fig. 4-7 show a circuit configuration of a rectifying unit and its rectified output voltage according to an embodiment of the present invention.

Fig. 4 shows a schematic circuit diagram of the rectifying unit 402 according to an embodiment of the present invention.

Referring to fig. 4, the rectifying unit 402 may include 8 diodes D01-D08 for converting an ac voltage output from a three-phase power supply via the port guard module 401 into a rectified voltage VA 1. The three-phase power supply comprises three phase lines V1, V2, V3 and a neutral line N. The port guard module 401 may include port guard resistors R01-R04. The embodiment of the present invention may not include the port protection module 401, and the rectifying unit 402 directly receives the ac voltage from the three-phase power supply.

As shown in fig. 4, the anode of the diode D01 is connected to the first phase line V1 of the three-phase power supply, and the cathode of the diode D01 is connected to the output terminal of the rectifying unit. An anode of the diode D02 is connected to the second phase line V2 of the three-phase power supply, and a cathode of the diode D02 is connected to the output terminal of the rectifying unit. The anode of the diode D03 is connected to the third phase line V3 of the three-phase power supply, and the cathode of the diode D03 is connected to the output terminal of the rectifying unit. The anode of the diode D04 is connected to the neutral line N of the three-phase power supply, and the cathode of the diode D04 is connected to the output terminal of the rectifying unit. The cathode of the diode D05 is connected to the first phase line V1 of the three-phase power supply, and the anode of the diode D05 is connected to the ground terminal. The cathode of the diode D06 is connected to the second phase line V2 of the three-phase power supply, and the anode of the diode D06 is connected to the ground terminal. The cathode of the diode D07 is connected to the third phase line V3 of the three-phase power supply, and the anode of the diode D07 is connected to the ground terminal. The cathode of the diode D08 is connected to the neutral line N of the three-phase power supply, and the anode of the diode D08 is connected to the ground.

The rectifying unit 402 described above can achieve rectification of an alternating voltage, however, the rectified voltage output by the rectifying unit in such a structure may have a very high direct current component, for example, as shown in fig. 7, VA1 has a direct current component of at least 480V. Therefore, such a rectified voltage does not fall below the set off threshold at any one time, and the entire linear power supply does not output any more. Therefore, it is necessary to improve the rectifying unit 402 so that the rectified voltage output by it can periodically fall below the set turn-off threshold.

Fig. 5 shows a schematic circuit diagram of a rectifying unit 502 according to another embodiment of the present invention.

In one embodiment, the rectifying unit 502 may include only 4 diodes D1-D4 for converting the ac voltage output from the three-phase power supply via the port protection module 501 into the rectified voltage VA 2. The three-phase power supply comprises three phase lines V1, V2, V3 and a neutral line N. The port guard module 501 is the same as the port guard module 401 in fig. 4, and the description thereof is omitted.

As shown in fig. 5, the anode of the diode D1 is connected to the first phase line V1 of the three-phase power supply, and the cathode of the diode D1 is connected to the output terminal of the rectifying unit. An anode of the diode D2 is connected to the second phase line V2 of the three-phase power supply, and a cathode of the diode D2 is connected to the output terminal of the rectifying unit. The cathode of the diode D3 is connected to the third phase line V3 of the three-phase power supply, and the anode of the diode D3 is connected to the ground terminal. The cathode of the diode D4 is connected to the neutral line N of the three-phase power supply, and the anode of the diode D4 is connected to the ground.

In the rectifying unit 502, since the alternating potentials of the three phase lines are not directed to the same end, the outputs of the three phases no longer form a rectified voltage having a higher direct current component due to complementation. As shown in fig. 7, the rectified voltage VA2 output by the rectifying unit with such a structure periodically falls below a set turn-off threshold, for example, the threshold may be set to a value in the range of 100V and 200V, such as 140V. Therefore, the control of the turn-on and turn-off of the step-down transistor switch T1 as described above can be realized, so that the average power consumption on the step-down transistor switch T1 can be reduced, and the overall efficiency can be improved.

Fig. 6 shows a schematic circuit diagram of a rectifying unit 602 according to another embodiment of the present invention.

In one embodiment, the rectifying unit 602 may include 6 diodes D1-D6 for converting an ac voltage output from a three-phase power source via the port guard module 601 into a rectified voltage VA 3. The three-phase power supply comprises three phase lines V1, V2, V3 and a neutral line N. The port guard module 601 is the same as the port guard module 401 in fig. 4 and the port guard module 501 in fig. 5, and the description thereof is omitted.

As shown in fig. 6, the diodes D1-D4 are connected between the four lines V1, V2, V3, and N of the three-phase power supply and the output terminal or the ground terminal of the rectifying unit 602 in the same manner as shown in fig. 5. The cathode of the diode D5 is connected to the second phase line V2 of the three-phase power supply, and the anode of the diode D5 is connected to the ground terminal. The anode of the diode D6 is connected to the neutral line N of the three-phase power supply, and the cathode of the diode D6 is connected to the output terminal of the rectifying unit.

Similar to the rectifying unit 502, in the rectifying unit 602, since the alternating voltages of the three phase lines are not directed to the same end, the outputs of the three phases no longer form a rectified voltage having a higher direct current component due to complementation. For example, as shown in fig. 7, the rectified voltage VA3 output by the rectifying unit with such a structure periodically falls below a set turn-off threshold, for example, the threshold may be set to a value in the range of 100V and 200V, such as 140V. Therefore, the control of the turn-on and turn-off of the step-down transistor switch T1 as described above can be realized, so that the average power consumption on the step-down transistor switch T1 can be reduced, and the overall efficiency can be improved.

The rectified voltage VA1 output by the rectifying unit 402 has a high dc component (e.g., about 500V, as shown in fig. 7), and the rectified voltage VA2 output by the rectifying unit 502 and the rectified voltage VA3 output by the rectifying unit 602 periodically drop to a very low voltage value (e.g., below 10V) and thus may drop below a set turn-off threshold, e.g., the threshold may be set to a value in the range of 100V to 200V, such as 140V.

Further, the performance of the rectifying unit 502 and the rectifying unit 602 are slightly different, as shown in table 1 below, where "√" indicates that the power supply between the several phase lines is normal, whereas "xx" indicates that the power supply between the several phase lines is abnormal (power loss or failure).

Table 1 comparison of performance of rectifying unit 502 and rectifying unit 602

Specifically, the rectifying unit 502 has advantages of a small number of diodes (4), and is more cost-effective, and has disadvantages that the single-phase power supplies AB and CN cannot work. The rectifying unit 602 has the disadvantage of having a large number of diodes (6), and has the advantage of operating normally for both single-phase and three-phase power supplies, ensuring high efficiency.

In view of practical situations (e.g., high cost, limited size of integrated module, power supply efficiency, etc.), those skilled in the art can make various suitable modifications to the rectifying

units

502 and 602, such as increasing or decreasing diodes connected between four lines of the three-phase power supply, the rectified output or the ground, to achieve the same purpose, i.e., periodically dropping the rectified voltage of the output below the threshold. Here, the periodic variation of the rectified voltage is obtained using the frequency of the three-phase power supply itself and the phase difference of the respective phase voltages, and therefore, it is not necessary to additionally provide an oscillation signal or a frequency source, thereby saving costs.

Fig. 8 shows a schematic circuit diagram of a linear power supply 800 according to an embodiment of the present invention.

According to the embodiment of the present invention, the linear power supply 800 may include a port protection module 801, a rectification unit 802, and a voltage transformation unit 803. As shown in fig. 8, in one embodiment, the port protection module 801 may be composed of port protection resistors R01-R04, the rectifying unit 802 may have the same structure as the rectifying unit 602 shown in fig. 6, and the transforming unit 803 may have the same structure as the transforming unit 303 shown in fig. 3. However, various combinations of substitutions and changes may be made by those skilled in the art to the various modules.

Next, the operation of the linear power supply 800 will be described by taking the linear power supply 800 shown in fig. 8 as an example.

Fig. 9A-9B show schematic performance graphs of a linear power supply 800, which are example simulation results, in accordance with embodiments of the present invention.

Fig. 9A shows a graph of the rectified voltage VA of the linear power supply 800, the voltage Vge between the gate and emitter of the buck transistor switch T1, and the voltage transforming unit output voltage VDD as a function of time. Fig. 9B shows a graph of the voltage drop Vce between the collector and the emitter of the buck transistor switch T1 and the current Ice over time. The operation of the linear power supply 800 can be divided into the following 4 stages P0-P3 in chronological order.

Starting phase P0: at power-up, since the enabling transistor switch T3 turns off to turn on the buck transistor switch T1 rapidly, thereby generating a momentarily large on current, Ice has a maximum value around 0ms (i.e., at power-up) (as shown in fig. 9B), and VDD rises rapidly (as shown in fig. 9A) since T1 is enabled to transmit voltage.

Thereafter, the emitter voltage of T3 rises rapidly to keep it on, thereby controlling the transistor switch T2 to resume control of the turn-on and turn-off of T1.

Stage P1: in the process of lowering VA from the highest value to the set threshold, T2 is in the on state because the control terminal input voltage is large enough, and T3 is also in the on state, so that the voltage between the gate and emitter of T1 is small and is in the off state.

In phase P1, the voltage Vce at T1 is relatively large, but the current Ice flowing through T1 is zero, as shown in fig. 9B.

Stage P2: as the VA value continues to decrease below the set threshold (approximately 140V as shown in FIG. 9A), T2 turns off and T1 turns on. The voltage Vge at the instant T1 turns on is larger and thus enters a saturation state, at the same time Ice has a maximum (as shown in fig. 9B) to charge the capacitor module 8031, and the capacitor module 8031 is rapidly charged. For T1, the voltage Vge at T1 drops from charging to full charge at the capacitor module 8031 to a constant value, so T1 self-regulates rapidly from saturation to amplification, maintaining a very low Ice. Here, the change of T1 between the saturation state and the amplification state is self-regulated by negative feedback.

In the phase P2, although there is always a voltage drop Vce across T1, the current is only large when T1 is on, and remains low for the rest of the time, so the average power consumption across T1 is still relatively low during this phase.

Stage P3:when VA rises back to the set threshold, T2 turns on, turning T1 off. When the VA change has passed the maximum, stage P1 is entered again.

In phase P3, similar to phase P1, the voltage Vce at T1 is relatively large, but the current Ice through T1 is zero, as shown in FIG. 9B.

During each operating cycle of the linear power supply 800 (phases P1-P3), the buck transistor switch T1 is periodically switched such that the current Ice is almost zero when the voltage difference Vce across T1 is large, and the voltage difference Vce varies over a lower range of values when the voltage difference Vce across T1 is large. Therefore, the overall average power consumption of T1 in the working period is lower, and the overall efficiency is improved. In other words, linear power supply 800 achieves the intended goal of turning on T1 only at low dropout or conducting current only at low dropout. Because the average power consumption is reduced, the working temperature is greatly reduced, and the working stability of the power supply is improved.

To sum up, the utility model discloses can realize following function or advantage: the linear power supply is self-adaptive to switch according to the frequency of the power grid, the switching frequency changes along with the power grid, and an oscillation signal does not need to be additionally provided; the rectified voltage after rectification can drop periodically, and high-efficiency energy transmission is realized through a rear-stage linear power supply at the voltage drop point; the voltage transformation unit is matched with the rectification unit, so that the switch of the voltage reduction transistor is switched on and has low power consumption when the voltage is lower than a set threshold, and the switch of the voltage reduction transistor is switched off and has no power consumption when the voltage is higher than the set threshold; the advantages of wide input range, high starting speed and EMC (electro magnetic compatibility) characteristics of the linear power supply are reserved; the higher efficiency makes possible the use of low cost linear power supplies in more appliances; the reduction of selected components is beneficial to the miniaturization of products.

The block diagrams of circuits, devices, apparatus, devices, and systems presented herein are meant to be illustrative examples only and are not intended to require or imply that the blocks, devices, and systems shown in the block diagrams must be connected or arranged or configured in a manner consistent with the teachings of the block diagrams. As will be appreciated by one skilled in the art, these circuits, devices, apparatus, devices, systems may be connected, arranged, configured in any manner that achieves the intended purposes.

It should be understood by those skilled in the art that the foregoing specific embodiments are merely exemplary and not limiting, and that various modifications, combinations, sub-combinations and substitutions may be made in the embodiments of the invention depending upon design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.

Claims

1. A linear power supply, comprising:

a rectifying unit for converting an alternating current voltage input from a three-phase power supply into a rectified voltage; and

a voltage transformation unit connected to the rectification unit for adjusting the rectified voltage output by the rectification unit, wherein

The voltage transformation unit comprises a voltage reduction transistor switch and a control transistor switch;

the voltage reduction transistor switch is connected between the output end of the rectification unit and the output end of the voltage transformation unit and is used for bearing the voltage difference between the output end of the rectification unit and the output end of the voltage transformation unit; and is

The control transistor switch is connected between the control end of the voltage reduction transistor switch and the output end of the voltage transformation unit, and the control end of the control transistor switch is controlled by the rectified voltage output by the rectification unit, so that the voltage reduction transistor switch is controlled to be turned off when the rectified voltage output by the rectification unit is larger than a threshold value.

2. The linear power supply of claim 1, wherein:

the transformation unit further comprises a first resistor, a first voltage stabilizing tube module, a second resistor, a second voltage stabilizing tube module and a third resistor;

a first end of the buck transistor switch is connected to an output end of the rectifying unit, a second end of the buck transistor switch is connected to an output end of the transforming unit, and a control end of the buck transistor switch is connected to the first end of the buck transistor switch through the first resistor;

a first end of the first resistor is connected to a first end of the buck transistor switch, and a second end of the first resistor is connected to a control end of the buck transistor switch;

the first end of the first voltage-stabilizing tube module is connected to the second end of the first resistor, the second end of the first voltage-stabilizing tube module is connected to the ground end, and the first end of the first voltage-stabilizing tube module is the voltage-stabilizing end of the first voltage-stabilizing tube module;

a first end of the control transistor switch is connected to a control end of the buck transistor switch, a second end of the control transistor switch is connected to a second end of the buck transistor switch, and the control end of the control transistor switch is connected to an output end of the rectifying unit through the second voltage stabilizing tube module and the third resistor;

the first end of the second voltage-stabilizing tube module is connected to the second end of the third resistor, the second end of the second voltage-stabilizing tube module is connected to the control end of the control transistor switch, the first end of the third resistor is connected to the output end of the rectifying unit, and the first end of the second voltage-stabilizing tube module is the voltage-stabilizing end of the second voltage-stabilizing tube module; and is

A first terminal of the second resistor is connected to the control terminal of the control transistor switch and a second terminal of the second resistor is connected to the second terminal of the control transistor switch.

3. The linear power supply of claim 1 or 2, wherein:

the rectifying unit comprises a first diode, a second diode, a third diode and a fourth diode;

the anode of the first diode is connected to a first phase line of the three-phase power supply, and the cathode of the first diode is connected to the output end of the rectifying unit;

the anode of the second diode is connected to a second phase line of the three-phase power supply, and the cathode of the second diode is connected to the output end of the rectifying unit;

the cathode of the third diode is connected to a third phase line of the three-phase power supply, and the anode of the third diode is connected to a ground terminal; and is

The cathode of the fourth diode is connected to the neutral line of the three-phase power supply, and the anode of the fourth diode is connected to the ground terminal.

4. The linear power supply of claim 3, wherein:

the rectifying unit further comprises a fifth diode and a sixth diode;

the cathode of the fifth diode is connected to the second phase line of the three-phase power supply, and the anode of the fifth diode is connected to the ground terminal; and is

An anode of the sixth diode is connected to a neutral line of the three-phase power supply, and a cathode of the sixth diode is connected to an output terminal of the rectification unit.

5. The linear power supply of claim 1 or 2, wherein the transforming unit further comprises a start transistor switch connected between the second terminal of the buck transistor switch and the second terminal of the control transistor switch.

6. The linear power supply of claim 5, wherein:

the voltage transformation unit further comprises a fourth resistor, a third voltage stabilization tube module and a fifth resistor;

the first end of the starting transistor switch is connected to the second end of the buck transistor switch, the second end of the starting transistor switch is connected to the second end of the control transistor switch, and the control end of the starting transistor switch is connected to the ground end through the fourth resistor and the third voltage stabilizing tube module;

the first end of the fourth resistor is connected to the control end of the starting transistor switch, the second end of the fourth resistor is connected to the first end of the third voltage-stabilizing tube module, the second end of the third voltage-stabilizing tube module is connected to the ground end, and the first end of the third voltage-stabilizing tube module is the voltage-stabilizing end of the third voltage-stabilizing tube module; and is

A first terminal of the fifth resistor is connected to the control terminal of the start transistor switch, and a second terminal of the fifth resistor is connected to the second terminal of the start transistor switch.

7. The linear power supply of claim 1 or 2, wherein:

the transformation unit further includes a capacitor module including one or more capacitors connected between an output terminal and a ground terminal of the transformation unit.

8. The linear power supply according to claim 1 or 2, further comprising a dc-dc converter connected to an output of the transforming unit.

9. The linear power supply according to claim 1 or 2, wherein the buck transistor switch is an IGBT, the control terminal of the buck transistor switch is a gate of the IGBT, the first terminal of the buck transistor switch is a collector of the IGBT, and the second terminal of the buck transistor switch is an emitter of the IGBT.

10. The linear power supply according to claim 1 or 2, wherein the control transistor switch is an NPN transistor, the control terminal of the control transistor switch is a base of the NPN transistor, the first terminal of the control transistor switch is a collector of the NPN transistor, and the second terminal of the control transistor switch is an emitter of the NPN transistor.

11. The linear power supply of claim 5, wherein the start transistor switch is a PNP transistor, the control terminal of the start transistor switch is a base of the PNP transistor, the first terminal of the control transistor switch is a collector of the PNP transistor, and the second terminal of the control transistor switch is an emitter of the PNP transistor.