WO2020186731A1

WO2020186731A1 - Ac/dc conversion power supply system

Info

Publication number: WO2020186731A1
Application number: PCT/CN2019/109902
Authority: WO
Inventors: 谢志和
Original assignee: 谢志和
Priority date: 2019-03-15
Filing date: 2019-10-08
Publication date: 2020-09-24
Also published as: CN109818414A

Abstract

An AC/DC conversion power supply system comprises a power supply and an operating frequency inverter connected to the power supply, and further comprises a direct current boost circuit connected to a direct current wiring terminal of a main board of the operating frequency inverter and a transformer selection relay connected to an alternating current wiring terminal. The direct current boost circuit is connected to a direct current charging relay and a contactor, and the contactor is connected to a rectification filter circuit. A control terminal of the transformer selection relay is connected to an output relay and a current detection circuit. The current detection circuit is connected to a mains inversion power supply selection relay. A normally closed terminal of the transformer selection relay is connected to a low-capacity transformer, and a normally open terminal thereof is connected to a first mains charging selection relay. A normally open terminal of the first mains charging selection relay is connected to the rectification filter circuit and then to the contactor, a normally closed terminal thereof is connected to a high-capacity transformer and then to a second mains charging selection relay, and a control terminal of the first mains charging selection relay is connected to a control terminal of the second mains charging selection relay.

Description

A power system for AC/DC conversion

Technical field

The present invention relates to the technical field of power supplies, in particular, a power supply system for AC/DC conversion.

Background technique

RV inverters are divided into power frequency inverters and high frequency inverters. At present, high frequency inverters are characterized by high conversion efficiency, but their durability and load impact resistance are poor. On the contrary, the power frequency inverter has lower efficiency than high frequency inverters, but has good reliability, durability and strong resistance to shock load. These two kinds of inverters have a common defect, that is, the standby power consumption will be relatively large. Take the 48V3000 watt inverter as an example, the standby power consumption is generally about 30 watts, even the best industrial frequency inverter on the market , Its standby power consumption has reached 20 watts. Although some manufacturers have introduced inverters with so-called energy-saving modes, such inverters are realized by frequently switching the inverter working circuit. In the energy-saving mode, the inverter has no stable and uninterrupted AC output. . As a result, the circuits of many low-power devices or high-power electrical appliances in standby mode cannot work stably, making the so-called energy-saving mode hardly practical.

In addition, most of the power systems used in RVs are distributed and individual devices that perform a single function. The battery converts to the city power using an inverter, and the vehicle charging uses an isolator or a DC power boost or step-down charger. Solar charging uses a separate solar charging controller. This is not only costly but also bulky. And the current inverter equipment has some shortcomings.

Summary of the invention

The purpose of the present invention is to provide an AC-DC conversion power supply system, which is used to solve the problem of large size and high cost of the power supply system of motor homes in the prior art and excessive energy consumption of the power supply system under standby conditions, or the failure of many devices in energy-saving mode Problem with normal work.

The present invention solves the above problems through the following technical solutions:

An AC/DC conversion power supply system includes a power supply and a power frequency inverter connected to the power supply, and also includes a DC boost circuit connected to the DC terminal of the main board of the power frequency inverter, and connected to the AC terminal The transformer selection relay; the DC boost circuit is connected with a DC charging relay and a contactor, the contactor is connected with a rectifier filter circuit; the control end of the transformer selection relay is connected with an output relay and a current detection circuit, and the current detection circuit is connected with The mains inverter power selection relay; the normally closed end of the transformer selection relay is connected with a small transformer, and the normally open end is connected with the first mains charging selection relay; the normally open end of the first mains charging selection relay is connected with the rectifier filter circuit to The normally closed end of the contactor is connected to the large transformer to the second mains charging selection relay, and the control end of the first mains charging selection relay is connected to the control end of the second mains charging selection relay. The invention uses a transformer selection relay to connect two transformers of different sizes and then to the main board of the power frequency inverter. The two transformers are commonly connected to the output relay, and a current detection circuit is connected to the output relay to detect the working current in the circuit. The transformer selection relay automatically switches the transformer according to the current in the circuit. When the load in the circuit is low, the small transformer is connected to the circuit to bear the load. When the load of the connected circuit becomes larger, the transformer selection relay automatically switches after the current in the circuit increases. The large transformer is connected to the circuit to bear the load. This design reduces the power consumption of the RV's power supply system under low load and standby conditions. For example, an 8kva inverter consumes only about 4 watts of standby power when using a 70 watt small transformer, which is much lower than the same type. The inverter has a standby power consumption of about 80 watts. It avoids the excessive loss of the electric energy stored in the power supply system itself, reduces waste, allows the electric energy of the power supply of the RV to be more fully utilized, greatly improves the battery life of the RV, and solves the large volume of the power system of the RV. High cost and high energy consumption of the power supply system under standby conditions, or many devices cannot work normally in energy-saving mode. At the same time, the circuit is also designed with a mains charging relay that can be charged with household electricity, and a DC charging relay is also added It can be charged by connecting a generator or solar panel through a DC charging circuit.

Preferably, the contactor is a multi-circuit relay or a plurality of combined single-circuit relays, with a variety of optional methods, which can complete the control of each branch, such as the relays and contactors used in the system The devices can be: single or multiple mechanical relays, solid state relays, or MOS tubes, triodes and other electronic components with switching functions.

Preferably, the rectifier and filter circuit is a full-bridge rectifier and filter circuit. The AC power is firstly rectified by the full-bridge to obtain a DC power with a certain AC component, and then a filter capacitor is connected in parallel to the positive and negative electrodes of the DC power to eliminate residual AC power and obtain pure The DC power is input to the DC boost module to avoid interference caused by the coexistence of AC and DC.

Preferably, the heat dissipation method adopted by the large transformer and the small transformer is dry air cooling, liquid cooling, or circulating cooling through the cooling tube of the outer coil of the transformer. The common cooling methods for transformers include dry air cooling and For liquid cooling, this system preferentially adopts dry air cooling and cooling liquid circulation through the outer plate cooling pipe to dissipate heat, which has better heat dissipation effect, and the cooling liquid is recycled, which is more economical. In addition, the circuit of the heat sink is equipped with an external interface, and the external fan can be started synchronously when the fan is working.

Preferably, the DC boost circuit can be directly connected to a DC generator or a solar panel for DC charging through a DC charging circuit. This charging function can be performed simultaneously with the inverter function. When using the power system, the generator can be used at the same time. Or solar panels can be used for DC charging, which is more convenient to use.

Preferably, the DC boost circuit is an isolated boost module or a non-isolated boost circuit. There are many types of boost circuits. Common boost circuits can also achieve the purpose of the present invention and have strong practicability.

Preferably, the current detection circuit is a coil induction detection circuit, a Hall current detection circuit or a DC shunt detection circuit, and the current detection circuit can be set at any position where the working current can be detected, and common current detection circuits can be implemented. The power supply for the relay achieves the purpose of automatically selecting the switching transformer. The position of the current detection circuit in the circuit is variable and can be integrated with the relay. It can be located between the inverter main board and the battery terminal, and the inverter main board and the function switching relay Between the function switching relay and the transformer selection relay, and between the output relay and the output terminal.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

(1) The design of the present invention reduces the power consumption of the RV's power supply system under low load and standby conditions. For example, an 8kva inverter consumes only about 4 watts when using a 70 watt small transformer in standby, which is greatly It is lower than the standby power consumption of inverters of the same type up to about 80 watts. It avoids the excessive loss of the electric energy stored in the power supply system itself, reduces waste, allows the electric energy of the power supply of the RV to be more fully utilized, greatly improves the battery life of the RV, and solves the large volume of the power system of the RV. High cost and high energy consumption of the power supply system under standby conditions, or many devices cannot work normally in energy-saving mode. At the same time, the circuit is also designed with a mains charging relay that can be charged with household electricity, and a DC charging relay is also added It can be charged by connecting a generator or solar panel through a DC charging circuit. And the DC charging can be performed synchronously when the inverter function is working, and it can even work without a battery and only relying on the low-voltage DC inverter input from the charging port.

(2) The rectifier and filter circuit of the present invention is a full-bridge rectifier and filter circuit. The alternating current is firstly rectified by the full bridge to obtain a direct current with a certain AC component, and then a filter capacitor is connected in parallel with the positive and negative electrodes of the direct current to eliminate residual alternating current and obtain pure The DC power is input to the DC boost module to avoid interference caused by the coexistence of AC and DC.

(3) The contactor connected in the present invention is a multi-circuit relay or a plurality of combined single-circuit relays. There are a variety of optional methods to complete the control of each branch. The relays and contacts used in the system Devices such as the device can be: single or multiple mechanical relays, solid state relays, or electronic components with switching functions such as MOS tubes and triodes.

(4) The current detection circuit of the present invention is a coil induction detection circuit, a Hall current detection circuit or a DC shunt detection circuit, and the current detection circuit can be set at any position where the working current can be detected. Common current detection circuits can be implemented The power supply for the relay achieves the purpose of automatically selecting the switching transformer. The position of the current detection circuit in the circuit is variable and can be integrated with the relay. It can be located between the inverter main board and the battery terminal, and the inverter main board and the function switching relay Between the function switching relay and the transformer selection relay, and between the output relay and the output terminal.

Description of the drawings

Fig. 1 is a schematic block diagram of the circuit structure of the RV power supply system of the present invention;

2 is a schematic block diagram of the circuit structure of Embodiment 2 of the present invention.

3 is a schematic block diagram of the circuit structure of Embodiment 3 of the present invention.

detailed description

The present invention will be further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

Example 1:

As shown in Figure 1, an AC/DC conversion power supply system includes a power supply and a power frequency inverter connected to the power supply, and also includes a DC boost circuit connected to the DC terminal of the main board of the power frequency inverter , And a transformer selection relay connected to the AC terminal; the DC boost circuit is connected with a DC charging relay and a contactor, and the contactor is connected with a rectifier filter circuit; the control terminal of the transformer selection relay is connected with an output relay and a current detection Circuit, the current detection circuit is connected with the mains inverter power selection relay; the normally closed end of the transformer selection relay is connected with a small transformer, and the normally open end is connected with the first mains charging selection relay; the normal of the first mains charging selection relay The open end is connected to the rectifier filter circuit to the contactor, the normally closed end is connected to the large transformer to the second mains charging selection relay, the control end of the first mains charging selection relay is connected to the control end of the second mains charging selection relay, The two mains charging selection relays separate the large transformer to charge the mains when the mains charging is needed. The inverter mainboard continues to be connected to the small transformer to play a role, because some inverter mainboards will automatically shut down if they are not connected to the transformer. , This is not conducive to the seamless switching of the two power sources.

The large transformer is 3000VA, and the small transformer is 100VA. The common cooling methods of the two transformers are dry air cooling and liquid cooling. This system adopts the cooling method of cooling liquid circulating through the outer plate cooling pipe to dissipate heat, and the heat dissipation effect is better. Recycling, more economical. The control terminals of the transformer selection relay and the output relay are connected by a synchronous control line to ensure the synchronous control of the two relays. The first mains charging selection relay and the second mains are respectively arranged between the large transformer and the transformer selection relay and the output relay. For the charging selection relay, the two mains charging relays are connected together through the second synchronization control line, which can ensure the synchronous control of the two mains relays.

Among them, the contactor is a multi-circuit relay or multiple combined single-circuit relays, with a variety of optional methods that can complete the control of each branch. The relays, contactors and other devices used in this system can be It is: single or multiple mechanical relays, solid state relays, or MOS tubes, triodes and other electronic components with switching functions. This embodiment adopts general relays. The rectifier and filter circuit is a full-bridge rectifier and filter circuit. The AC power is firstly rectified by the full bridge to obtain a DC power with a certain AC component, and then a filter capacitor is connected in parallel with the positive and negative electrodes of the DC power to eliminate the residual AC power to obtain pure DC power and then input to DC boost module to avoid interference caused by the coexistence of AC and DC. The current detection circuit is a coil induction detection circuit, a Hall current detection circuit or a DC shunt detection circuit, and the current detection circuit can be set at any position where the working current can be detected. Common current detection circuits can be used to power the relay automatically. The purpose of selecting the switching transformer, the position of the current detection circuit in the circuit is variable, it can be integrated with the relay, it can be located between the inverter main board and the battery terminal, between the inverter main board and the function switching relay, and the function is switched Between relay and transformer selection relay, between output relay and output terminal.

Another advantage is that the DC boost circuit can be directly connected to the DC generator or solar panel for DC charging through the DC charging circuit. This charging function can be performed simultaneously with the inverter function. When using this power system, it can be used to generate electricity. It is more convenient to use for direct current charging by the machine or solar panel.

Example 2:

On the basis of embodiment 1, combined with Figure 2, the power supply system of this touring car can be used as a power frequency inverter alone, the power frequency inverter is reserved, and the transformer selection relay is directly connected to the AC output of the power frequency inverter main board Then connect a 3000VA transformer and a 100VA transformer, and connect the output relay. At the same time, the output relay is connected to the transformer selection relay through the relay synchronization control line, and the output relay is connected to the load appliance; similarly, when the load of the output circuit is small , The low-power transformer is connected to the circuit to bear the load, and the load of the connected circuit is large. After the current becomes large, the detection circuit supplies power to the selection relay and automatically selects the switching transformer. This design reduces the standby power, and the size of the power system is greatly reduced, which brings more possibilities to the design of the RV.

Example 3:

With reference to Figure 3, on the basis of embodiment 1, an AC-DC conversion power supply system includes a power supply and a power frequency inverter connected to the power supply, and also includes a power frequency inverter connected to the main board of the power frequency inverter. Function selection relay and DC boost circuit; function selection relay is connected with rectifier filter circuit, transformer selection relay, output relay and mains charging relay and output relay is connected with mains charging relay, transformer selection relay is connected with output relay, and transformer selection A 3000VA transformer and a 100VA transformer are connected between the relay and the output relay. The high-power transformer and the low-power transformer adopt the cooling method of cooling liquid circulating through the outer plate cooling tube to dissipate heat. The common cooling methods of the transformer are dry air cooling and liquid cooling. The system adopts the cooling method of circulating cooling liquid through the outer plate cooling pipe to dissipate heat, which has better heat dissipation effect, and the cooling liquid is recycled and used more economically. The transformer selection relay is an integrated body of the current detection circuit and the relay; the DC boost module is connected with The contactor module and the DC charging relay, and the contactor module is connected to the rectification filter circuit, the full bridge rectification filter circuit adopted in this embodiment, the AC power is first obtained through the full bridge rectification to obtain a DC power with a certain AC component, and then a filter capacitor is used Connect the positive and negative poles of the direct current in parallel to eliminate residual alternating current, and obtain pure direct current and input it to the DC boost module to avoid interference caused by the coexistence of AC and DC. In this design, the current detection circuit is connected to the function selection relay, and then two transformers of different power are connected through the function selection relay. The low-power transformer is connected to the normally closed end of the function selection relay, and the high-power transformer is connected to the normally open end of the first transformer. When the load is low, the small power transformer is connected to the circuit to bear the load. When the load of the connected circuit becomes larger, the current in the circuit changes. When the current detection circuit detects that the current increases to the current threshold of the designed circuit, it is a function selection The relay power supply enables the high-power transformer to access the circuit to bear the load.

Although the present invention has been described with reference to the illustrative embodiments of the present invention, the above-mentioned embodiments are only preferred embodiments of the present invention, and the embodiments of the present invention are not limited by the above-mentioned embodiments. It should be understood that those skilled in the art Many other modifications and implementations can be designed, and these modifications and implementations will fall within the scope and spirit of the principles disclosed in this application.

Claims

A power supply system for AC/DC conversion includes a power supply and a power frequency inverter connected to the power supply, and is characterized in that it also includes a transformer selection relay connected to the AC terminal of the main board of the power frequency inverter, and a transformer selection relay A large transformer and a small transformer are connected, and the large transformer and the small transformer are simultaneously connected to the output relay.
The AC-DC conversion power supply system according to claim 1, further comprising a DC boost circuit connected to the DC terminal of the main board of the industrial frequency inverter, and a transformer selection relay connected to the AC terminal The DC boost circuit is connected with a DC charging relay and a contactor, and the contactor is connected with a rectifier filter circuit; the control end of the transformer selection relay is connected with an output relay and a current detection circuit, and the output relay is connected with the current detection circuit. The electric inverter power supply selection relay, the small transformer is connected between the normally closed end of the transformer selection relay and the output relay and the current detection circuit, and the normally open end of the transformer selection relay is connected with the first mains charging selection relay; the first The normally open terminal of the mains charging selection relay is connected to the rectifier filter circuit, the control end of the first mains charging selection relay is connected to the control end of the second mains charging selection relay, and the large transformer is connected to the first mains charging selection relay Between the normally closed terminal and the second mains charging selection relay.
The AC-DC conversion power supply system according to claim 2, wherein the relays and contactors are multiple relays or multiple single-circuit relays in combination, or solid-state relays and MOS transistors that also have switching functions. , Transistor.
The power supply system for AC-DC conversion according to claim 2, wherein the rectifier filter circuit is a full-bridge rectifier filter circuit.
The AC-DC conversion power supply system according to claim 1, characterized in that: the heat dissipation method adopted by the large transformer and the small transformer is dry air cooling, liquid cooling, or circulating cooling liquid through the cooling tube on the outer plate of the transformer The way of heat dissipation.
The AC-DC conversion power supply system according to claim 2, wherein the DC boost circuit can be directly connected to a DC generator or a solar panel for DC charging through a DC charging circuit, and the charging function can be combined with the inverter function Simultaneously.
The AC/DC conversion power supply system of claim 2, wherein the DC boost circuit is an isolated boost module or a non-isolated boost circuit.
The AC-DC conversion power supply system according to claim 2, wherein the current detection circuit is a coil induction detection circuit, a Hall current detection circuit or a DC shunt detection circuit, and the current detection circuit can be set in any energy The location where the operating current is detected.
The AC-DC conversion power supply system according to claim 1, characterized in that it further comprises a function selection relay and a DC boost circuit connected to the main board of the industrial frequency inverter; the function selection relay is connected with a rectifier filter circuit, The transformer selection relay, the output relay, and the mains charging relay, and the output relay is connected with the mains charging relay; the DC boost circuit is connected with a contactor module and a DC charging relay, and the contactor module is connected to a rectifier filter circuit Connect with DC charging relay.
The AC/DC conversion power supply system according to any one of claims 1-9, wherein the transformer selection relay is an integrated body of a current detection circuit and a relay.