CN106787898A - Overhaul power output device - Google Patents

Abstract

The present invention provides a maintenance power supply output device, comprising: a power supply circuit for providing a 12V DC voltage as an initial voltage; a push-pull boost circuit for converting the 12V DC voltage output by the power supply circuit into a 110V DC voltage and outputting it; The boost chopper circuit is used to convert the 110V DC voltage output by the push-pull boost circuit into 345V DC voltage; the inverter circuit is used to convert the 345V DC voltage boosted by the boost chopper circuit into 380V AC voltage and output. The present invention can provide DC12V, DC110V, and AC380V three voltage levels as output, which can meet more than 90% of substation construction load requirements, and is safe and flexible to use; it avoids the link of long-distance lead-in cables, shortens the start-up time of construction operations, and avoids The risk of over-level tripping of station power consumption due to maintenance of power supply connections is eliminated.

Description

A maintenance power output device

technical field

The invention relates to the technical field of electric power systems, in particular to a maintenance power supply output device.

Background technique

In recent years, with the addition of technical transformation and repair projects in various substations, inbound construction projects have increased, and maintenance power supplies are frequently used in various substation locations. The way to obtain the maintenance power is generally to lead the cables from the maintenance box in the station, which has the following disadvantages:

On the one hand, the location of the maintenance power box installed in the station is limited and fixed, and cannot cover all locations in the station. The use of the power supply in the box often requires long-distance cable connections, which brings inconvenience to on-site construction. Especially when the construction site is located in a remote location such as the roof of the substation or a wall, it will be very difficult to lead the power supply.

On the other hand, referring to the experience of safety accidents in substation external construction units using maintenance power sources in history, the reason is that the distance between the long-distance cables leading to the maintenance power supply and the transformer incoming line is too close, resulting in induced voltage and causing cable discharge. This shows that the long-distance cables leading to the maintenance power supply are likely to generate induced voltages with other live equipment, resulting in safety risks; in addition, cable dragging, entanglement, and insulation damage may also bring personal and equipment safety risks at the construction site.

Finally, there are risks of insulation damage and leakage protection function failure in some old-fashioned maintenance power supply boxes. Once a short-circuit fault occurs on the construction site, it will cause the switch in the box and even the switch of the incoming line of the station to trip over the level. Risk of loss of pressure.

Contents of the invention

The technical problem to be solved by the present invention is to provide a maintenance power output device with simple structure, flexible connection and reliable operation.

In order to solve the above technical problems, the present invention provides a maintenance power output device, including:

A power supply circuit for providing 12V DC voltage as the initial voltage;

Push-pull boost circuit, used to convert the 12V DC voltage output by the power supply circuit into 110V DC voltage and output it;

Boost chopper circuit for converting the 110V DC voltage output by the push-pull booster circuit into 345V DC voltage;

The inverter circuit is used for converting the 345V DC voltage boosted by the step-up chopper circuit into 380V AC voltage and outputting it.

Wherein, the power supply circuit includes two sets of lithium iron phosphate batteries connected in parallel, and each set consists of four lithium iron phosphate batteries with a rated voltage of 3V connected in series.

Wherein, 100A fuses are connected in series before and after the power supply circuit, which are used to fuse when the output current exceeds 100A to protect the storage battery.

Wherein, the 12V DC voltage is led to the output of the KM1 contactor.

Wherein, the push-pull boost circuit includes:

A push-pull boost conversion circuit, which further includes a switching element MOS tube, a high-frequency transformer, and a first PWM modulation circuit, which is used to turn off the 12V output of the power supply circuit by alternately turning off the switching element MOS tube. Convert DC voltage to high frequency square wave AC voltage;

A single-phase bridge-type full-control rectification circuit is used to rectify the high-frequency square-wave AC voltage into a 110V DC square-wave voltage.

Wherein, the push-pull boost circuit also includes:

The LC absorption network composed of the inductor and the capacitor is used to suppress the voltage spike of the collector of the MOS transistor, and output the 110V DC square wave voltage through the capacitor.

Wherein, the 110V DC voltage is connected to the KM2 contactor switch output.

Wherein, the step-up chopper circuit includes an inductor, a MOS transistor, a diode and a capacitor.

Wherein, the inverter circuit includes:

A three-phase voltage-type inverter circuit, which further includes an IGBT tube, a diode, and a second PWM modulation circuit, for boosting and inverting the 345V DC voltage output by the step-up chopper circuit to a 380V AC voltage, and leading to the isolated transformer.

Wherein, the inverter circuit also includes:

The isolation transformer is used to lead the 380V AC voltage to the KM3 switch output through the output switch 3ZK.

The beneficial effects of the embodiments of the present invention are:

The present invention can provide DC12V, DC110V, AC380V three kinds of voltage levels as output, which can meet more than 90% of substation construction load requirements, and is safe and flexible to use;

The present invention avoids the link of long-distance cable connection, and shortens the start time of construction work: currently, due to the requirements of the temporary power supply access regulations in the substation, the temporary power supply access must perform procedures such as switch characteristic testing and management personnel's signature to ensure safe operation At the same time, it also prolongs the start-up time of construction work, and the use of this device will eliminate the link of connecting cables, thereby shortening the start-up time and improving work efficiency; in addition, it also avoids the problem of over-level tripping of station power due to the lead-in of power supply for maintenance risk;

The present invention is a mobile device, so it can be placed along with the construction site, no matter where the construction site is located on the roof of the main control building at a high place or remote places such as substation walls and gates, the device can be used to supply power, which is flexible and convenient;

The device circuit of the present invention is simple, the device is light and easy to carry, and the device failure rate is low, and the operation reliability is high. It can be used as a powerful supplement for the power supply of the fixed inspection box in the substation, overcomes the weakness of the traditional method, and improves the safety of the construction site. level, ensuring the reliable operation of the station power supply;

The present invention can also be extended to occasions where mobile power supplies with above-mentioned voltage levels are required in ordinary civil electric power industries, and has wide application and promotion value.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a structural block diagram of a maintenance power output device according to an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of a power supply circuit in an embodiment of the present invention.

FIG. 3 is a schematic structural diagram of a push-pull boost circuit in an embodiment of the present invention.

Fig. 4 is a schematic diagram of the specific structure of the boost chopper circuit in the embodiment of the present invention.

Fig. 5 is a schematic diagram of the specific structure of the inverter circuit in the embodiment of the present invention.

Fig. 6 is a schematic structural diagram of a maintenance power output device according to an embodiment of the present invention.

detailed description

The following descriptions of various embodiments refer to the accompanying drawings to illustrate specific embodiments in which the present invention can be implemented.

Please refer to Figure 1, the embodiment of the present invention provides a maintenance power output device, including:

A power supply circuit for providing 12V DC voltage as the initial voltage;

Push-pull boost circuit, used to convert the 12V DC voltage output by the power supply circuit into 110V DC voltage and output it;

Boost chopper circuit for converting the 110V DC voltage output by the push-pull booster circuit into 345V DC voltage;

The inverter circuit is used for converting the 345V DC voltage boosted by the step-up chopper circuit into 380V AC voltage and outputting it.

That is to say, the maintenance power output device in this embodiment includes three voltage conversion circuits to provide three kinds of output voltages. The DC12V voltage is provided by the power supply circuit as the initial voltage (the first output voltage). Since most of the current substation power loads have a DC load voltage level of DC110V and an AC load of AC380V, the push-pull boost circuit outputs DC110V As the second output voltage, it can supply most of the DC loads and the PWM modulation circuit power in all circuits of the device. The step-up chopper circuit converts 110V DC voltage to 345V DC voltage as the input of the inverter circuit, and the inverter circuit converts the 345V DC voltage to 380V AC voltage as the third output voltage to meet the needs of most AC loads .

Please refer to FIG. 2 , specifically, to ensure reliability, the power supply circuit includes two sets of lithium iron phosphate batteries connected in parallel, and each set consists of four lithium iron phosphate batteries connected in series. Each battery cell has a rated capacity of 100Ah and a rated voltage of DC 3V. After being connected in series, the manual output switch 1ZK can stably output DC 12V voltage. Compared with the traditional lead-acid battery, the lithium iron phosphate battery pack has an energy ratio of 4-5 times that of the latter, and has the advantages of small size and light weight; the battery pack is connected in series with 100A fuses R1-R4, when the output current exceeds 100A , the fuse is blown to protect the battery pack; connect the DC 12V voltage to the KM1 contactor to obtain the first output voltage (DC 12V).

The push-pull boost circuit uses the DC12V output from the power supply circuit as the voltage input of the circuit to complete the conversion from DC12V to DC110V. The push-pull boost circuit in this embodiment is shown in Figure 3. Switching components MOS tubes Q1, Q2, high-frequency transformer T1 and PWM modulation circuit form a push-pull boost conversion circuit, and the switching components MOS tube Q1 , Q2 is turned off alternately, and the input voltage DC12V is converted into a high frequency square wave AC voltage. Diodes D1-D4 form a single-phase bridge fully-controlled rectification circuit, which rectifies the high frequency square wave AC voltage into a DC square wave voltage DC110V. L1 and C6 form an LC absorption network to suppress MOS tube collector voltage spikes. Output the high-frequency square wave voltage DC110V through C6, and connect the DC110V voltage to the KM2 contactor switch to obtain the second output voltage.

The principle of this circuit is:

(1) When 0≤t≤t1, Q1 is on and Q2 is off, there are:

(1)

(2)

Among them, N2 is the number of turns of W2.

(2) When t1≤t≤t2, Q1 and Q2 are cut off.

(3) When t2≤t≤t3, Q1 is off and Q2 is on, there are:

(3)

so

(4) When t3≤t≤t4, Q1 and Q2 are cut off.

Therefore, the output voltage U ₃ is an AC square wave with an amplitude of 1000, and a high-frequency square wave voltage with an amplitude of 2000000000000000000000000000000000000000000000000000000000000000 after full-bridge rectification. By adjusting the duty cycle of the power switches Q1 and Q2, the effective value of the output voltage can be adjusted.

Please refer to Figure 4, the step-up chopper circuit includes inductor L2, MOS transistor V3, diode D1, and capacitor C7, which together form a step-up DC/DC converter, which boosts DC110V to about DC345V.

Its circuit principle is:

When the MOS transistor V3 is turned on, the input voltage U _i is applied to the inductance L2, and the inductance L2 is excited by the input voltage U _i . During the conduction period, the magnetic flux increases by In the on state, the voltage (U _o -U _i ) is applied to the inductance L2 in the opposite direction to that when the switch is on, and the inductance L2 is demagnetized, and the magnetic flux decreases during the switch off period. In a steady state, the increase and decrease of the magnetic flux of the inductor are equal, and the voltage ratio of the step-up converter is less than 1. Since the transformation ratio is less than 1, the output voltage is always higher than the input voltage, which is a boost converter.

in,

Therefore, the output voltage U _o can be adjusted by adjusting the ratio of t _on +t _off to t _off .

In order to accurately obtain the output of the subsequent inverter circuit with an AC 380V amplitude, in the step-up chopper circuit, the original input voltage DC110V can be boosted to DC345V as the input of the subsequent inverter circuit.

Please refer to Figure 5 again, the inverter circuit uses the DC345V voltage output by the step-up chopper circuit as the voltage input of this circuit. IGBT tubes BG1-BG6, diodes Q5-Q10 and PWM modulation circuit form a three-phase voltage type inverter circuit, which jointly inverts DC345V to AC380V and leads to isolation transformer T2. The output voltage AC380V of the isolation transformer T2 is connected to the KM3 switch through the output switch 3ZK to obtain the third output voltage.

It can be seen from the above description that implementing the embodiment of the present invention has the following beneficial effects:

The present invention can provide DC12V, DC110V, AC380V three kinds of voltage levels as output, which can meet more than 90% of substation construction load requirements, and is safe and flexible to use;

The present invention avoids the link of long-distance cable connection, and shortens the start time of construction work: currently, due to the requirements of the temporary power supply access regulations in the substation, the temporary power supply access must perform procedures such as switch characteristic testing and management personnel's signature to ensure safe operation At the same time, it also prolongs the start-up time of construction work, and the use of this device will eliminate the link of connecting cables, thereby shortening the start-up time and improving work efficiency; in addition, it also avoids the problem of over-level tripping of station power due to the lead-in of power supply for maintenance risk;

The present invention is a mobile device, so it can be placed along with the construction site, no matter where the construction site is located on the roof of the main control building at a high place or remote places such as substation walls and gates, the device can be used to supply power, which is flexible and convenient;

The device circuit of the present invention is simple, the device is light and easy to carry, and the device failure rate is low, and the operation reliability is high. It can be used as a powerful supplement for the power supply of the fixed inspection box in the substation, overcomes the weakness of the traditional method, and improves the safety of the construction site. level, ensuring the reliable operation of the station power supply;

The present invention can also be extended to occasions where mobile power supplies with above-mentioned voltage levels are required in ordinary civil electric power industries, and has wide application and promotion value.

The above disclosures are only preferred embodiments of the present invention, and certainly cannot limit the scope of rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope of the present invention.

Claims (10)

1. An inspection power output apparatus, comprising:

the power supply circuit is used for providing 12V direct current voltage as initial voltage;

the push-pull type booster circuit is used for converting the 12V direct-current voltage output by the power supply circuit into 110V direct-current voltage and outputting the 110V direct-current voltage;

the boost chopper circuit is used for converting the 110V direct-current voltage output by the push-pull boost circuit into 345V direct-current voltage;

and the inverter circuit is used for converting the 345V direct-current voltage boosted by the boost chopper circuit into 380V alternating-current voltage and outputting the voltage.

2. The maintenance power output device of claim 1, wherein the power supply circuit comprises two sets of lithium iron phosphate storage batteries connected in parallel, each set being formed by connecting 4 lithium iron phosphate storage batteries with a rated voltage of 3V in series.

3. Service power output device according to claim 2, characterized in that the power supply circuit is connected in series with a 100A fuse (R1-R4) in front and behind for fusing to protect the battery when the output current exceeds 100A.

4. The service power output device of claim 2, wherein the 12V DC voltage is directed to the KM1 contactor output.

5. The service power output device of claim 1, wherein the push-pull boost circuit comprises:

the push-pull type boost conversion circuit further comprises switching element MOS (Q1, Q2), a high-frequency transformer (T1) and a first PWM (pulse width modulation) modulation circuit, and is used for converting the 12V direct-current voltage output by the power supply circuit into high-frequency square-wave alternating-current voltage through the alternate turn-off of the switching element MOS (Q1, Q2);

and the single-phase bridge type fully-controlled rectifying circuit is used for rectifying the high-frequency square wave alternating voltage into 110V direct-current square wave voltage.

6. The service power output device of claim 5, wherein the push-pull boost circuit further comprises:

an LC absorption network consisting of an inductor (L1) and a capacitor (C6) is used for suppressing the peak of the collector voltage of the MOS transistor and outputting the 110V direct current square wave voltage through the capacitor (C6).

7. The service power output device of claim 6, wherein the 110V DC voltage is directed to a KM2 contactor switch output.

8. The service power output apparatus according to claim 1, wherein the boost chopper circuit includes an inductor (L2), a MOS transistor (V3), a diode (D1), and a capacitor (C7).

9. The service power output apparatus of claim 1, wherein the inverter circuit comprises:

the three-phase voltage type inverter circuit further comprises IGBT tubes (BG 1-BG 6), diodes (Q5-Q10) and a second PWM modulation circuit, and is used for boosting and inverting 345V direct-current voltage output by the boosting chopper circuit to 380V alternating-current voltage and leading the voltage to an isolation transformer (T2).

10. The service power output apparatus of claim 9, wherein the inverter circuit further comprises:

and the isolation transformer (T2) is used for leading the 380V alternating voltage to the KM3 switch output through the output switch 3 ZK.