Water pump starting control device

Abstract

The utility model relates to a water pump starting control device which comprises a first frequency converter, a first isolating switch, a first switching unit, a first bypass unit interlocked with the first switching unit, a second frequency converter, a second isolating switch, a second switching unit and a second bypass unit interlocked with the second switching unit. The first disconnecting switch and the second disconnecting switch are interlocked, the first switching unit and the first bypass unit are both automatic switching switches, and the second switching unit and the second bypass unit are both manual switching switches; the first switching unit is connected in series with the first frequency converter and then connected in parallel with the first bypass unit. The second switching unit is connected in series with the second frequency converter and then connected in parallel with the second bypass unit. The first disconnecting switch and the second disconnecting switch control connection and disconnection between the first switching unit and the water pump and connection and disconnection between the second switching unit and the water pump respectively. The direct connection and indirect connection of the water pump and the generator are realized by changing the on-off of the bypass of the frequency converter.

Description

TECHNICAL FIELD

[0001] The utility model relates to water pump electric control technical field, concretely relates to a water pump starting control device. BACKGROUND

[0002] Water pumps are widely used in various industrial, agricultural and civilian fields. When water pumps are used in agriculture, they are mainly used for irrigation. When the driving mode of the water pump is motor driving and the distance from the power supply station is far, the pump motor of the water pump is usually powered after being powered by a diesel generator;

[0003] A diesel generator can indeed be directly connected to a water pump. As long as the output voltage, frequency and phase of the diesel generator match the requirements of the water pump, it can directly power the equipment. However, in actual application, directly connecting the equipment has certain risks. First, direct connection may cause damage to the equipment. The output voltage and current of the generator may not be stable, and once it exceeds the bearing range of the equipment, it may cause damage to the equipment. In addition, if the frequency and phase of the generator do not match the equipment, it may also cause the equipment to malfunction or be damaged. Second, direct connection may have safety hazards. The generator may generate high temperature, sparks and other dangerous factors during operation, which may cause fires, electric shocks and other safety accidents if directly connected to the equipment. Therefore, in order to ensure electrical safety, it is recommended to use an indirect connection method. Specifically, a power conversion device such as a voltage stabilizer, frequency converter, etc. can be added between the generator and the equipment to stabilize the output voltage and current and ensure that the frequency and phase match. At the same time, overload protection, short circuit protection and other safety measures can be added to improve electrical safety.

[0004] However, when the water pump is powered by the generator output current after power conversion by the frequency converter, if the pump motor of the water pump does not need to be powered by the frequency converter, the frequency converter needs to be removed and reconnected, resulting in the failure of the frequency converter function, increasing the number of electrical equipment, increasing the cost or increasing the labor of equipment disassembly. UTILITY MODEL CONTENTS

[0005] In order to solve the technical problems such as the risk of failure of the frequency converter function and the increase of labor for equipment disassembly when the water pump is powered by the generator output current after power conversion by the frequency converter, and the pump motor of the water pump does not need to be powered by the frequency converter, the utility model provides a water pump starting control device.

[0006] The technical solution of the utility model to solve the above technical problems is as follows:

[0007] The water pump starting control device comprises a first frequency converter, a first isolating switch, a first switching unit, a first bypass unit, a second frequency converter, a second isolating switch, a second switching unit and a second bypass unit, the first isolating switch is interlocked with the second isolating switch, the first switching unit and the first bypass unit are automatic switching switch units, and the second switching unit and the second bypass unit are manual switching switch units.

[0008] One end of the first isolating switch is connected with a water pump, the other end of the first isolating switch is connected with one end of the first switching unit, the other end of the first switching unit is connected with an output end of the first frequency converter, and an input end of the first frequency converter is connected with a power supply bus; one end of the first bypass unit is connected with one end of the first switching unit, and the other end of the first bypass unit is connected with an input end of the first frequency converter; the first switching unit is interlocked with the first bypass unit.

[0009] One end of the second isolating switch is connected with a water pump, the other end of the second isolating switch is connected with one end of the second switching unit, the other end of the second switching unit is connected with an output end of the second frequency converter, and an input end of the second frequency converter is connected with the power supply bus; one end of the second bypass unit is connected with one end of the second switching unit, and the other end of the second bypass unit is connected with an input end of the second frequency converter; the second switching unit is interlocked with the second bypass unit.

[0010] The water pump starting control device comprises a first frequency converter, a first isolating switch, a first switching unit, a first bypass unit, a second frequency converter, a second isolating switch, a second switching unit and a second bypass unit, the first isolating switch is interlocked with the second isolating switch, the first switching unit and the first bypass unit are automatic switching switch units, and the second switching unit and the second bypass unit are manual switching switch units.

[0011] On the basis of the above technical scheme, the utility model still can make improvement as follows.

[0012] Further, a third switching unit and a fourth switching unit are further included, the third switching unit is an automatic switching unit, and the fourth switching unit is a manual switching unit.

[0013] One end of the third switching unit is connected to the input end of the first frequency converter, and the other end of the third switching unit is connected to the power supply bus; the other end of the first switching unit is connected to the other end of the third switching unit.

[0014] One end of the fourth switching unit is connected to the input end of the second frequency converter, and the other end of the fourth switching unit is connected to the power supply bus; the other end of the second switching unit is connected to the other end of the fourth switching unit.

[0015] The beneficial effect of the above further scheme is that, by setting the third switching unit and the fourth switching unit, the on-off of the circuit where the frequency converter is located can continue to be controlled in the case of short circuit of the first switching unit and the second switching unit.

[0016] Further, the first switching unit includes a first AC contactor, the main contact of one end of the first AC contactor is connected to the other end of the first disconnecting switch, the main contact of the other end of the first AC contactor is connected to the output end of the first frequency converter, one end of the first bypass unit is connected to the main contact of one end of the first AC contactor, and the first AC contactor is interlocked with the first bypass unit.

[0017] Further, the first bypass unit includes a second AC contactor and a third disconnecting switch, one end of the third disconnecting switch is connected to the main contact of one end of the first AC contactor, the other end of the third disconnecting switch is connected to the main contact of one end of the second AC contactor, and the main contact of the other end of the second AC contactor is connected to the other end of the third switching unit.

[0018] Further, the third switching unit includes a third AC contactor, the main contact of one end of the third AC contactor is connected to the input end of the first frequency converter, and the main contact of the other end of the third AC contactor is connected to the power supply bus and the main contact of the other end of the second AC contactor, respectively.

[0019] Further, the second switching unit includes a fourth disconnecting switch, one end of the fourth disconnecting switch is connected to the other end of the second disconnecting switch, the other end of the fourth disconnecting switch is connected to the output end of the first frequency converter, one end of the second bypass unit is connected to one end of the fourth disconnecting switch, and the fourth disconnecting switch is interlocked with the second bypass unit.

[0020] Further, the second bypass unit comprises a fifth isolating switch, one end of the fifth isolating switch is connected with one end of the fourth isolating switch, and the other end of the fifth isolating switch is connected with the other end of the fourth switching unit.

[0021] Further, the fourth switching unit comprises a sixth isolating switch, one end of the sixth isolating switch is connected with the input end of the second frequency converter, and the main contact of the other end of the sixth isolating switch is connected with the power supply bus and the other end of the fifth isolating switch respectively.

[0022] Further, the fourth switching unit comprises a sixth isolating switch, one end of the sixth isolating switch is connected with the input end of the second frequency converter, and the main contact of the other end of the sixth isolating switch is connected with the power supply bus and the other end of the fifth isolating switch respectively.

[0023] In order to solve the above technical problems, the utility model also provides a control water pump starting's electrical cabinet, its specific technical content is as follows:

[0024] A control water pump starting's electrical cabinet, including the cabinet body, be configured with above-mentioned water pump starting control device in the cabinet body. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The electrical schematic diagram of the utility model. DETAILED DESCRIPTION

[0026] The principles and characteristics of the utility model are described below in combination with the drawings, and the examples are only used to explain the utility model and are not used to limit the scope of the utility model.

[0027] As Figure 1As shown, this embodiment provides a water pump start control device, including a first frequency converter U1, a first disconnect switch QS1, a first switching unit, a first bypass unit, a second frequency converter U2, a second disconnect switch QS2, a second switching unit, and a second bypass unit. The first disconnect switch QS1 and the second disconnect switch QS2 are interlocked. The first switching unit and the first bypass unit are both automatic switching units, and the second switching unit and the second bypass unit are both manual switching units. One end of the first disconnect switch QS1 is connected to the water pump M, and the other end of the first disconnect switch QS1 is connected to one end of the first switching unit. The other end of the first switching unit is connected to the output terminal of the first frequency converter U1. The input terminal of inverter U1 is connected to the power supply bus; one end of the first bypass unit is connected to one end of the first switching unit, and the other end of the first bypass unit is connected to the input terminal of the first inverter U1; the first switching unit and the first bypass unit are interlocked; one end of the second disconnect switch QS2 is connected to the water pump M, the other end of the second disconnect switch QS2 is connected to one end of the second switching unit, the other end of the second switching unit is connected to the output terminal of the second inverter U2, and the input terminal of the second inverter U2 is connected to the power supply bus; one end of the second bypass unit is connected to one end of the second switching unit, and the other end of the second bypass unit is connected to the input terminal of the second inverter U2; the second switching unit and the second bypass unit are interlocked.

[0028] In some embodiments, the water pump start control device further includes a third switching unit and a fourth switching unit. The third switching unit is an automatic switching unit, and the fourth switching unit is a manual switching unit. One end of the third switching unit is connected to the input terminal of the first frequency converter U1, and the other end of the third switching unit is connected to the power supply bus. The other end of the first switching unit is connected to the other end of the third switching unit. One end of the fourth switching unit is connected to the input terminal of the second frequency converter U2, and the other end of the fourth switching unit is connected to the power supply bus. The other end of the second switching unit is connected to the other end of the fourth switching unit.

[0029] By setting up a third and a fourth switching unit, the switching on and off of the circuit containing the frequency converter can continue to be controlled even if the first and second switching units are short-circuited.

[0030] The first switching unit includes a first AC contactor KM1. One end of the main contact of the first AC contactor KM1 is connected to the other end of the first disconnector switch QS1. The other end of the main contact of the first AC contactor KM1 is connected to the output terminal of the first frequency converter U1. One end of the first bypass unit is connected to the main contact of one end of the first AC contactor KM1. The first AC contactor KM1 is interlocked with the first bypass unit. The first bypass unit includes a second AC contactor KM2 and a third disconnector switch QS3. One end of the third disconnector switch QS3 is connected to the main contact of one end of the first AC contactor KM1. The other end of the third disconnector switch QS3 is connected to the main contact of one end of the second AC contactor KM2. The other end of the main contact of the second AC contactor KM2 is connected to the other end of the third switching unit. The third switching unit includes a third AC contactor KM3. The main contact of one end of the third AC contactor KM3 is connected to the input terminal of the first frequency converter U1, and the main contact of the other end of the third AC contactor KM3 is connected to the power supply bus and the main contact of the other end of the second AC contactor KM2, respectively.

[0031] The first disconnector QS1 and the second disconnector QS2 are integrated into a single multi-pole double-throw (MPD) disconnector. Specifically, the MPD and QS2 are interlocked by connecting their common terminal to the pump motor of the water pump M via a wire. The two ends of the MPD are connected to the first switching unit and the second switching unit, respectively. One end of the MPD and the common terminal together constitute the first disconnector QS1, and the other end of the MPD and the common terminal together constitute the second disconnector QS2.

[0032] The interlocking mechanism between the second AC contactor KM2, the third AC contactor KM3, and the first AC contactor KM1 is as follows: The electromagnetic coils of the third AC contactor KM3 and the first AC contactor KM1 are connected in series to the A control terminal of a controller, such as a PLC (Programmable Logic Controller). The A control terminal of the PLC is connected to the electromagnetic coil of the second AC contactor KM2. Simultaneously, the main contacts of the third AC contactor KM3 and the first AC contactor KM1 are connected using normally closed contacts, while the main contacts of the second AC contactor KM2 are connected using normally open contacts. This achieves interlocking between the second AC contactor KM2, the third AC contactor KM3, and the first AC contactor KM1. When the third AC contactor KM3 and the first AC contactor KM1 are closed, the second AC contactor KM2 is open; when the second AC contactor KM2 is closed, the third AC contactor KM3 and the first AC contactor KM1 are open.

[0033] In some embodiments, the second switching unit includes a fourth disconnect switch QS4, one end of which is connected to the other end of the second disconnect switch QS2, and the other end of which is connected to the output terminal of the first frequency converter U1. One end of the second bypass unit is connected to one end of the fourth disconnect switch QS4, and the fourth disconnect switch QS4 is interlocked with the second bypass unit. The second bypass unit includes a fifth disconnect switch QS5, one end of which is connected to one end of the fourth disconnect switch QS4, and the other end of which is connected to the other end of the fourth switching unit. The fourth switching unit includes a sixth disconnect switch QS6, one end of which is connected to the input terminal of the second frequency converter U2, and the main contacts of the other end of which are respectively connected to the power supply bus and the other end of the fifth disconnect switch QS5.

[0034] The fifth disconnector QS5 is interlocked with both the fourth disconnector QS4 and the sixth disconnector QS6 as follows: Both the fourth disconnector QS4 and the sixth disconnector QS6 are multi-pole double-shunt disconnectors, with each switch isolated from the others. The common terminal A of the multi-pole double-shunt disconnectors is connected to the second disconnector QS2. A contact at one end of the common terminal A of the multi-pole double-shunt disconnectors is connected to the output terminal of the second frequency converter U2. The input terminal of the second frequency converter U2 is connected to the common terminal B of the multi-pole double-shunt disconnectors. A contact at one end of the common terminal B of the multi-pole double-shunt disconnectors is connected to the power supply bus. The contact at the other end corresponding to the common terminal A and the contact at the other end corresponding to the common terminal B of the multi-pole double-switch disconnector are connected to the power supply bus. Thus, when the disconnector of the multi-pole double-switch disconnector is placed at one end of the multi-pole double-switch disconnector, both the fourth disconnector QS4 and the sixth disconnector QS6 are turned on, and the fifth disconnector QS5 is turned off. When the disconnector of the multi-pole double-switch disconnector is placed at the other end of the multi-pole double-switch disconnector, both the fourth disconnector QS4 and the sixth disconnector QS6 are turned off, while the fifth disconnector QS5 is turned on, thus achieving interlocking between the fifth disconnector QS5 and both the fourth disconnector QS4 and the sixth disconnector QS6.

[0035] In some embodiments, the pump start control device further includes a first circuit breaker QF1 and a second circuit breaker QF2. One end of the first circuit breaker QF1 is connected to the other end of the third switching unit, and the other end of the first circuit breaker QF1 is connected to the power supply bus. One end of the second circuit breaker QF2 is connected to the other end of the fourth switching unit, and the other end of the second circuit breaker QF2 is connected to the power supply bus.

[0036] This embodiment of the invention sets up two switching units for frequency converters, and controls the on / off state of each switching unit with two interlocked isolating switches. This allows for manual switching of the bypass modes of the two switching units. When the first isolating switch QS1 is closed and the second isolating switch QS2 is open, the bypass of the frequency converter circuit is in automatic switching mode, suitable for applications with fixed loads. When the second isolating switch QS2 is closed and the first isolating switch QS1 is open, the bypass of the frequency converter circuit is in manual switching mode, suitable for applications with uncertain loads. In automatic switching mode, with the first isolating switch QS1 closed and the second isolating switch QS2 open, if the current through the first frequency converter U1 is too high (exceeding the rated current), it indicates that the first frequency converter U1 is damaged and short-circuited. In this case, the first AC contactor KM1 or the third AC contactor KM3 is open, and the second AC contactor KM2 is closed. The current flows through the bypass of the first frequency converter U1, preventing damage to other electrical components caused by damage to the first frequency converter U1. In manual switching mode, the first isolating switch QS1 is open and the second isolating switch QS2 is closed. When the current through the second frequency converter U2 is too large, i.e., exceeds the rated current, it indicates that the second frequency converter U2 is short-circuited due to damage. Then, the fourth isolating switch QS4 and the sixth isolating switch QS6 are manually opened and the fifth isolating switch QS5 is closed. The current bypasses the second frequency converter U2 to prevent damage to other electrical components caused by the damage to the second frequency converter U2.

[0037] In some other embodiments, an electrical cabinet for controlling the start of a water pump is also provided, including a cabinet body, in which the aforementioned water pump start control device is disposed. The number of cabinet bodies can be two: a first disconnecting switch QS1, a third AC contactor KM3, a first frequency converter U1, a second AC contactor KM2, a third disconnecting switch QS3, and a first circuit breaker QF1 are disposed in one cabinet body; a second disconnecting switch QS2, a fourth disconnecting switch QS4, a second frequency converter U2, a sixth disconnecting switch QS6, a fifth disconnecting switch QS5, and a second circuit breaker QF2 are disposed in the other cabinet body. The two cabinet bodies respectively realize automatic bypass and manual bypass of the frequency converter. By replacing the cabinet bodies, the cabinet maintenance efficiency can be improved, and the automatic bypass and manual bypass functions can be modularized.

[0038] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the concept and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A water pump start-up control device, characterized in that: It includes a first frequency converter (U1), a first disconnect switch (QS1), a first switching unit, a first bypass unit, a second frequency converter (U2), a second disconnect switch (QS2), a second switching unit, and a second bypass unit. The first disconnect switch (QS1) and the second disconnect switch (QS2) are interlocked. The first switching unit and the first bypass unit are both automatic switching units, and the second switching unit and the second bypass unit are both manual switching units. One end of the first disconnecting switch (QS1) is connected to the water pump (M), and the other end of the first disconnecting switch (QS1) is connected to one end of the first switching unit. The other end of the first switching unit is connected to the output terminal of the first frequency converter (U1), and the input terminal of the first frequency converter (U1) is connected to the power supply bus. One end of the first bypass unit is connected to one end of the first switching unit, and the other end of the first bypass unit is connected to the input terminal of the first frequency converter (U1). The first switching unit and the first bypass unit are interlocked. One end of the second disconnecting switch (QS2) is connected to the water pump (M), and the other end of the second disconnecting switch (QS2) is connected to one end of the second switching unit. The other end of the second switching unit is connected to the output terminal of the second frequency converter (U2), and the input terminal of the second frequency converter (U2) is connected to the power supply bus. One end of the second bypass unit is connected to one end of the second switching unit, and the other end of the second bypass unit is connected to the input terminal of the second frequency converter (U2). The second switching unit and the second bypass unit are interlocked.

2. The water pump start control device according to claim 1, characterized in that: It also includes a third switching unit and a fourth switching unit, wherein the third switching unit is an automatic switching unit and the fourth switching unit is a manual switching unit; One end of the third switching unit is connected to the input terminal of the first frequency converter (U1), and the other end of the third switching unit is connected to the power supply bus; the other end of the first switching unit is connected to the other end of the third switching unit. One end of the fourth switching unit is connected to the input terminal of the second frequency converter (U2), and the other end of the fourth switching unit is connected to the power supply bus; the other end of the second switching unit is connected to the other end of the fourth switching unit.

3. The water pump start control device according to claim 2, characterized in that: The first switching unit includes a first AC contactor (KM1), one end of the main contactor (KM1) is connected to the other end of the first disconnect switch (QS1), the other end of the first AC contactor (KM1) is connected to the output terminal of the first frequency converter (U1), one end of the first bypass unit is connected to the main contactor of one end of the first AC contactor (KM1), and the first AC contactor (KM1) is interlocked with the first bypass unit.

4. The water pump start control device according to claim 3, characterized in that: The first bypass unit includes a second AC contactor (KM2) and a third disconnecting switch (QS3). One end of the third disconnecting switch (QS3) is connected to the main contact of one end of the first AC contactor (KM1), and the other end of the third disconnecting switch (QS3) is connected to the main contact of one end of the second AC contactor (KM2). The main contact of the other end of the second AC contactor (KM2) is connected to the other end of the third switching unit.

5. The water pump start control device according to claim 4, characterized in that: The third switching unit includes a third AC contactor (KM3). The main contact of one end of the third AC contactor (KM3) is connected to the input terminal of the first frequency converter (U1), and the main contact of the other end of the third AC contactor (KM3) is connected to the power supply bus and the main contact of the other end of the second AC contactor (KM2).

6. The water pump start control device according to claim 2, characterized in that: The second switching unit includes a fourth disconnect switch (QS4), one end of which is connected to the other end of the second disconnect switch (QS2), the other end of which is connected to the output terminal of the first frequency converter (U1), one end of the second bypass unit is connected to one end of the fourth disconnect switch (QS4), and the fourth disconnect switch (QS4) is interlocked with the second bypass unit.

7. The water pump start control device according to claim 6, characterized in that: The second bypass unit includes a fifth disconnecting switch (QS5), one end of which is connected to one end of the fourth disconnecting switch (QS4), and the other end of which is connected to the other end of the fourth switching unit.

8. The water pump start-up control device according to claim 7, characterized in that: The fourth switching unit includes a sixth disconnect switch (QS6), one end of which is connected to the input terminal of the second frequency converter (U2), and the main contacts of the other end of the sixth disconnect switch (QS6) are respectively connected to the power supply bus and the other end of the fifth disconnect switch (QS5).

9. The water pump start control device according to claim 2, characterized in that: It also includes a first circuit breaker (QF1) and a second circuit breaker (QF2). One end of the first circuit breaker (QF1) is connected to the other end of the third switching unit, and the other end of the first circuit breaker (QF1) is connected to the power supply bus. One end of the second circuit breaker (QF2) is connected to the other end of the fourth switching unit, and the other end of the second circuit breaker (QF2) is connected to the power supply bus.

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