A high-voltage frequency converter load motor safety control system

Abstract

The utility model discloses a kind of high-voltage frequency converter load motor safety control system, belong to high-voltage frequency converter safety design field.Through the cooperation of main control loop and auxiliary control loop, the start-stop state of heater can be completely dependent on the judgment logic whether motor is running.Different from traditional single temperature control type heater control mode, the intelligent control concept of reverse triggering heating of motor operating state is introduced, that is, only in the state that frequency conversion operation and power frequency operation are not detected, heater is allowed to work, solve the problem that motor is prone to damp during shutdown in wet and cold environment, and effectively avoid overheating risk when running.Its creativity not only reflects the linkage judgment mechanism of automatic identification motor working state, but also in the clear closed-loop construction of system logic path.

Description

Technical Field

[0001] This application relates to the field of safety design for high-voltage frequency converters, and in particular to a safety control system for a load motor of a high-voltage frequency converter. Background Technology

[0002] With the continuous development of industrial equipment, high-voltage frequency converters and other electrical equipment are widely used in various load motor drive systems. Starting load motors in high humidity and low temperature environments often faces numerous challenges. Especially in high humidity environments, water droplets may form on the surface of the load motor, which can affect its operation, reduce its insulation performance, and lead to safety hazards. Furthermore, starting a load motor in low temperature environments may adversely affect the performance of the motor materials, thereby reducing its service life.

[0003] Traditional load motor heating control systems are typically complex and costly, unable to adapt to diverse environmental conditions and potentially causing overheating and unnecessary damage to the load motor. Therefore, there is an urgent need for a simple yet effective control system to ensure the normal operation of load motors in high humidity and low temperature environments and to extend their lifespan. Utility Model Content

[0004] This utility model provides a safety control system for a high-voltage frequency converter load motor. It can solve the aforementioned problems existing in related technologies. The technical solution is as follows:

[0005] A safety control system for a load motor of a high-voltage frequency converter is provided. The system is used for the load motor of the high-voltage frequency converter. The system includes a motor heater, and a main control circuit and an auxiliary control circuit connected to the motor heater.

[0006] The main control circuit includes a circuit breaker and a main circuit contactor, and the auxiliary control circuit includes a relay group (7) and a main circuit contactor control coil (C);

[0007] The relay group (7) is used to control the energization state of the main circuit contactor control coil (C) by means of a closed state, wherein the energization state of the main circuit contactor control coil (C) automatically controls the energization state of the main circuit contactor, the energization state of the main circuit contactor automatically controls the power supply conduction state of the main control circuit, and the power supply conduction state of the main control circuit automatically controls the start and stop of the motor heater.

[0008] Optionally, the system further includes a control power supply terminal, which provides AC 220V power.

[0009] The control power supplied by the control power supply terminal is input to the circuit breaker and output to each circuit through the circuit breaker. Part of the control power output by the circuit breaker is connected to the main control circuit, and the other part is connected to the auxiliary control circuit.

[0010] Optionally, the relay group (7) includes a motor frequency conversion operation monitoring relay (SSXA) and a motor power frequency monitoring relay (SSXB) that are normally closed and connected in series;

[0011] The main circuit contactor control coil (C) is connected in series with the relay group (7).

[0012] Optionally, the main control circuit is also provided with a reserved interface for external power supply.

[0013] Optionally, the main circuit contactor control coil (C) is provided with terminal 1 (A1) and terminal 2 (A2).

[0014] Optionally, the coil circuit is equipped with a surge absorber (8) for overcurrent protection of the main circuit contactor control coil (C).

[0015] Optionally, the circuit breaker is a BW32SAG-2P010 type and supports manual control;

[0016] The main circuit contactor is of type MC-SH1 and supports automatic control;

[0017] The surge absorber (8) is model SZ-Z5.

[0018] Optionally, the circuit breaker and the main circuit contactor are located at both ends of the control power supply, which are the live wire side and the neutral wire side.

[0019] The relay group (7) and the main circuit contactor control coil (C) are connected in parallel at the two ends.

[0020] By coordinating the main control loop and the auxiliary control loop, the heater's start-up and shutdown status can be entirely dependent on the logic of whether the motor is running. This design differs from traditional single-temperature-control heater control methods, introducing an intelligent control concept of "motor running status triggering heating." That is, the heater is only allowed to operate when neither variable frequency nor mains frequency operation is detected, solving the problem of motor moisture absorption during shutdown in humid and cold environments and effectively avoiding the risk of overheating during operation. Its innovation lies not only in the linkage judgment mechanism for automatically identifying the motor's operating status but also in the clear closed-loop construction of the system's logical path.

[0021] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of a high-voltage inverter load-side heater control system provided in an illustrative embodiment of this application. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0025] Example 1

[0026] like Figure 1 As shown, a safety control system for a load motor of a high-voltage frequency converter is provided. The system is used for the load motor of the high-voltage frequency converter and includes a motor heater, as well as a main control circuit and an auxiliary control circuit connected to the motor heater.

[0027] The main control circuit includes a circuit breaker and a main circuit contactor, while the auxiliary control circuit includes a relay group 7 and a main circuit contactor control coil C.

[0028] Relay group 7 is used to control the energization state of the main circuit contactor control coil C through the closed state. The energization state of the main circuit contactor control coil C automatically controls the energization state of the main circuit contactor, the energization state of the main circuit contactor automatically controls the power supply conduction state of the main control circuit, and the power supply conduction state of the main control circuit automatically controls the start and stop of the motor heater.

[0029] The system first uses the normally closed-open logic of relay groups SSXA and SSXB to distinguish between the two states of "variable frequency operation" and "power frequency operation" in real time. When neither is triggered, the control coil C of the main circuit contactor is energized, which further drives the main circuit contactor 1, thus connecting the main control circuit and supplying power to the motor heater. This forms a reverse linkage closed loop of "motor stop - heater start, motor start - heater stop". This not only dehumidifies and prevents moisture during shutdown but also completely avoids secondary overheating during operation, significantly improving insulation reliability and motor life.

[0030] This application embodiment, through the coordination of the main control loop and the auxiliary control loop, enables the heater's start-up and shutdown status to depend entirely on the judgment logic of whether the motor is running. This design differs from traditional single-temperature-control type heater control methods, introducing the intelligent control concept of "motor running status triggering heating in reverse." That is, the heater is only allowed to operate when neither variable frequency nor mains frequency operation is detected, solving the problem of easy moisture absorption during motor shutdown in humid and cold environments and effectively avoiding the risk of overheating during operation. Its innovation lies not only in the linkage judgment mechanism for automatically identifying the motor's operating status but also in the clear closed-loop construction of the system's logical path.

[0031] Example 2

[0032] Optionally, the system also includes a control power supply terminal, which provides AC 220V power.

[0033] The control power supply provided by the control power supply terminal is input to the circuit breaker and output to each circuit through the circuit breaker. Among them, part of the control power supply output by the circuit breaker is connected to the main control circuit and the other part is connected to the auxiliary control circuit.

[0034] Optionally, relay group 7 includes a normally closed motor frequency conversion operation monitoring relay SSXA and a motor power frequency monitoring relay SSXB connected in series, and the main circuit contactor control coil C is connected in series with relay group 7.

[0035] The following explains the working process of the safety control system, combined with... Figure 1 .

[0036] Another part of the control power supply output from the circuit breaker is connected to the auxiliary control circuit. Its function is to assist in the control by connecting two control signal relays, SSXA and SSXB. Relay SSXA is normally closed and is used to generate the motor frequency conversion operation signal, while relay SSXB is normally closed and is used to generate the motor power frequency operation signal.

[0037] This enables the automatic start / stop function of the motor heater. The control power supply provides 220V AC power. When the circuit is energized, relay SSXA trips from its normally closed position, de-energizing the auxiliary control circuit and the main circuit contactor control coil C. Consequently, the main control circuit is also not conducting, supplying power to the motor heater, and the motor heater cannot operate. Only when the motor is not running, relays SSXA and SSXB are in their normally closed positions, energizing the main circuit contactor control coil C. This energizes the main circuit contactor, causing it to engage and power on, allowing the motor heater to operate.

[0038] In terms of the environment, the motor itself generates heat when it is running. If the motor heater reheats it, it will damage the motor. The main purpose of the heater is to heat the air environment around the motor to ensure that the surrounding area is dry when the motor is not running. The heater controls the operation of the motor to evaporate the surrounding moisture before the motor can run.

[0039] By introducing 220V AC at the control power supply terminal and feeding the same power to the main and auxiliary circuits separately via circuit breakers, the two control chains are ensured to operate synchronously under the same phase reference. Simultaneously, the circuit breakers provide overload and short-circuit protection for both power supplies. Power fluctuations will not cause asynchronous or false triggering of the two logic circuits, resulting in more stable heater start-stop response and improved overall system immunity and safety margin.

[0040] In summary, this embodiment not only rationally divides the 220V AC power to the main control circuit and the auxiliary control circuit, but also achieves centralized management and shunt protection through circuit breakers, thereby improving the overall power supply stability and control reliability of the system. The series normally closed design of relays SSXA and SSXB not only improves the robustness against false triggering, but also enables the system to independently determine the two operating modes of frequency conversion and power frequency. Its sensitive response to complex switching states in industrial scenarios provides a low-cost, highly intelligent control strategy.

[0041] Furthermore, the motor's operating status is determined by the linkage between the closed and open states of SSXA and SSXB, thereby controlling the energizing path between contactor 2 and contactor 1, ultimately affecting the heater's operation. This design is not a simple parallel control, but rather constructs a progressively layered electrical judgment chain, unlike previous control approaches that relied on time relays or temperature sensors.

[0042] Example 3

[0043] The main control circuit also has a reserved interface for external power supply, for example, if other components require control power supply. Figure 1 As shown, external connections can be made within the loop, and there are no restrictions on this.

[0044] Furthermore, the main circuit contactor control coil C is equipped with terminals 1A1 and 2A2, which serve as input and output terminals for power transmission.

[0045] In addition, the control power supply is AC, and the voltage and current may be unstable. The circuit may absorb excessive current. In order to prevent the contactor coil from being impacted, the coil circuit is equipped with a surge absorber 8 for overcurrent protection of the main circuit contactor control coil C.

[0046] The addition of a power supply reserved interface in the main circuit and the A1 / A2 standard terminals of the contactor provide plug-and-play capability for subsequent external temperature and humidity sensors, remote monitoring, or cloud-based diagnostic modules. Functionality can be expanded without altering existing wiring, significantly improving system maintainability and lifecycle upgrade potential.

[0047] This application embodiment provides a direct access path for potential external control components by including a reserved interface. Especially in large-scale frequency converter systems, multiple auxiliary units such as remote temperature control and cloud monitoring platforms may need to be linked with the main circuit; this design provides a flexible interface for integration and system-level optimization. Simultaneously, the standardized layout of the contactor's terminal definitions A1 and A2 facilitates modular maintenance and reduces replacement and commissioning costs in industrial settings.

[0048] Example 4

[0049] In actual production operations, in order to match the applicant's developed products, the following types of components can be used to form a safety control system.

[0050] In one example, the circuit breaker is a BW32SAG-2P010 type and supports manual control. The main circuit contactor is an MC-SH1 type and supports automatic control. The surge absorber 8 is an SZ-Z5 model.

[0051] This application demonstrates that the application is not only theoretically sound, but has also been verified through actual selection, and is ready for mass production. By specifying the circuit breaker model BW32SAG-2P010, the contactor model MC-SH1, and the surge absorber model SZ-Z5, this application shows that it is not only theoretically sound, but has also been verified through actual selection.

[0052] Example 5

[0053] Optionally, the circuit breaker and the main circuit contactor are located at both ends of the control power supply, with the two ends being the live wire side and the neutral wire side, and the relay group 7 and the main circuit contactor control coil C are connected in parallel at both ends.

[0054] This embodiment of the application significantly improves the electrical balance and response agility of the system by placing the circuit breaker and main circuit contactor on the live wire side and neutral wire side of the control power supply, respectively, and by connecting the auxiliary contactor and relay group in parallel. This layout not only conforms to the safety design principles of electrical engineering, but also provides a physical basis for fault isolation and rapid repair of different circuits.

[0055] The above are merely optional embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A safety control system for a high-voltage frequency converter load motor, characterized in that, The system is used for the load motor of a high-voltage frequency converter. The system includes a motor heater, as well as a main control circuit and an auxiliary control circuit connected to the motor heater. The main control circuit includes a circuit breaker and a main circuit contactor, and the auxiliary control circuit includes a relay group (7) and a main circuit contactor control coil (C); The relay group (7) is used to control the energization state of the main circuit contactor control coil (C) by means of a closed state, wherein the energization state of the main circuit contactor control coil (C) automatically controls the energization state of the main circuit contactor, the energization state of the main circuit contactor automatically controls the power supply conduction state of the main control circuit, and the power supply conduction state of the main control circuit automatically controls the start and stop of the motor heater.

2. The control system according to claim 1, characterized in that, The system also includes a control power supply terminal, which provides AC 220V power. The control power supplied by the control power supply terminal is input to the circuit breaker and output to each circuit through the circuit breaker. Part of the control power output by the circuit breaker is connected to the main control circuit, and the other part is connected to the auxiliary control circuit.

3. The control system according to claim 1, characterized in that, The relay group (7) includes a normally closed motor frequency conversion operation monitoring relay (SSXA) and a motor power frequency monitoring relay (SSXB) connected in series; The main circuit contactor control coil (C) is connected in series with the relay group (7).

4. The control system according to claim 1, characterized in that, The main control circuit is also equipped with a reserved interface for external power supply.

5. The control system according to claim 1, characterized in that, The main circuit contactor control coil (C) is provided with terminal 1 (A1) and terminal 2 (A2).

6. The control system according to claim 1, characterized in that, The coil circuit is equipped with a surge absorber (8) for overcurrent protection of the main circuit contactor control coil (C).

7. The control system according to claim 6, characterized in that, The circuit breaker is a BW32SAG-2P010 model and supports manual control; The main circuit contactor is of type MC-SH1 and supports automatic control; The surge absorber (8) is model SZ-Z5.

8. The control system according to claim 2, characterized in that, The circuit breaker and the main circuit contactor are located at both ends of the control power supply, which are the live wire side and the neutral wire side. The relay group (7) and the main circuit contactor control coil (C) are connected in parallel at the two ends.

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