Energy-saving electric cabinet for hydraulic pumps in die-casting machines and industrial machinery

Abstract

This invention relates to a power conditioning cabinet for hydraulic pumps in die-casting machines and industrial equipment. The cabinet includes: a cabinet housing, circuit breakers and protectors, a central controller, an inverter, a discharge resistor, a pressure monitoring sensor for the accumulator tank, a cabinet ventilation system, and an indicator light. After connecting to the die-casting machine's control circuit system, the cabinet performs three main functions: controlling the operation of the hydraulic pump, regulating the accumulator tank pressure based on the feedback pressure signal, and automatically warning of errors in the system. The hydraulic system of the die-casting machine operates based on cylinders and hydraulic valves, which are automatically controlled by the system's PLC program.

Description

Technical Field

[0001] The present invention relates to a power cabinet, specifically an energy-saving power cabinet for a die-casting machine and a hydraulic pump system of an industrial machine, also known as a "hydraulic pump power adjustment cabinet".

Background Art

[0002] A die-casting machine operates based on the pressure provided by a hydraulic pump. Pressure die-casting machine technology uses a hydraulic valve system to control the automatic operation of each stage and phase of the operating cycle. To produce a product that meets quality requirements after die-casting, it is necessary for the hydraulic system to meet factors related to the pressure and speed of the actuator operated by the hydraulic system. Considering the sequence of stages, the power consumption of the hydraulic pump can be divided into two processes. Refer to the diagram of the operating cycle stage of the die-casting machine (Figure 10).

[0003] (Useful power supplied to the pump) Generate the work amount required to execute the necessary machine cycle, including the following main stages: mold closing stage; accumulator pressure filling (executed in multiple cycles scattered between stages); mold opening stage (executed in two mold closing cycles and one mold opening cycle); product discharging stage from the mold core (executed in two cycles of forward and backward movement of the product discharging cylinder).

[0004] (Wasted power supplied to the pump) The hydraulic pump does not generate work amount, but the operation continues. The pump consumes energy, but the generated pressure is discharged and returned to the oil tank without participating in the operation of the hydraulic actuator. It includes the following stages: die-casting pressure generation stage (pressure obtained from the accumulator), product removal stage from the machine by the robot (excluding the work amount generation cycle), mold release agent spraying stage.

[0005] Based on the above analysis, it was found that the process of "wasted power supplied to the pump" is an energy-wasting process, and that technical measures are needed to save energy without affecting the machine's operation. Based on our expertise in industrial control equipment and deep knowledge of die-casting machine systems, we have researched and filed a patent application for a power cabinet that adjusts the power consumption of hydraulic pumps in die-casting machines and industrial machinery to save energy during production and for widespread application to other factories in the industrial sector. [Overview of the project]

[0006] The present invention relates to a power cabinet for regulating the power consumption of hydraulic pumps in die-casting machines and industrial machinery. This cabinet is used to conserve energy by controlling the hydraulic pump during cycles when the pump is not generating work but is still operating—where energy is wasted and the temperature of the system and working environment rises.

[0007] To address the above issues, a power cabinet for regulating the power consumption of hydraulic pumps in die-casting machines and industrial machinery consists of the following main components: power cabinet housing, switching and protection devices, central controller, inverter, discharge resistor, accumulator pressure monitoring sensor, power cabinet ventilation system, and indicator lights (see Figure 1).

[0008] After being connected to the die-casting machine's control system, the power cabinet performs three main functions: controlling the operation of the hydraulic pump; controlling the accumulator pressure based on the feedback pressure signal; and automatically warning of system failures (see Figure 2). [Brief explanation of the drawing]

[0009] [Figure 1] This diagram shows a power cabinet composed of its main components. [Figure 2] This is a schematic diagram of the control connection to the die-casting machine. [Figure 3] This diagram shows an overall overview of the power cabinet. [Figure 4] This figure shows switching and protection devices. [Figure 5] This diagram shows the central controller. [Figure 6] This is a diagram of an inverter. [Figure 7] This is a diagram showing a discharge resistor block. [Figure 8] This diagram shows an accumulator pressure monitoring sensor. [Figure 9] This is a diagram showing a power cabinet ventilation system. [Figure 10] This diagram shows the stages of the die-casting machine's operating cycle. [Figure 11] This diagram shows the use of signals to control the operation of a hydraulic pump. [Modes for carrying out the invention]

[0010] The following description is the best way to carry out the present invention. This section is intended to illustrate the general features of the present invention and is not intended to limit it. The scope of the present invention is most clearly defined by the appended claims.

[0011] Refer to Figure 1. The power cabinet for regulating the power consumption of hydraulic pumps in die-casting machines and industrial machinery according to the present invention includes the following components: power cabinet housing, switching and protection devices 7, central controller 1, inverter 2, discharge resistor 3, accumulator pressure monitoring sensor 4, power cabinet ventilation system, indicator light 5. Details:

[0012] (Electrical cabinet) Refer to Figure 3. The electrical cabinet includes the system framework and mounting surfaces for the main components. The sides and door of the cabinet are cut with appropriate holes for indicator lights and cooling fans. The cabinet door is sealed with a gasket to prevent water vapor and dust from entering the system.

[0013] (Circuit breakers and protectors) (7) Refer to Figure 4. These devices handle the switching of power and control circuits within the cabinet and provide protection against overload and short circuits in the event of a fault.

[0014] (Central Controller) (1) Refer to Figure 5. This component determines control signals, receives feedback signals, and calculates control and system alerts. Its functions are as follows: The central controller is programmed with a control program according to the operating requirements of the die-casting machine cycle. The central controller is signal-connected to the variable frequency drive, issues control commands to the variable frequency drive, and receives feedback regarding its operation. The central controller is connected to the die-casting machine via signals, receives signals requesting power supply to the hydraulic pump, and operates according to the machine cycle. The central controller is connected to the feedback signal from the accumulator's pressure sensor and calculates and controls the hydraulic pump to supply hydraulic pressure according to the machine's setting requirements. • The central controller is connected to indicator lights to show operation and warn of system failures. The central controller is connected to temperature sensors within the cabinet and calculates and controls the cabinet's cooling and ventilation fan system.

[0015] (Inverter (VFD)) (2) Refer to Fig. 6. The inverter (VFD) is the main power device that controls the power consumption of the hydraulic pump motor in the most reasonable way. The type of inverter is selected according to the load characteristics of the hydraulic pump and the ability to meet the high starting torque, ensuring the stable and accurate operation of the system. In order for the inverter to operate properly and meet the requirements, the setting parameters of the inverter also need to be appropriately measured and calculated based on the actual operation of the die-casting machine. The inverter is a power device that distributes power to the hydraulic pump and is connected to the central controller for control and warning signals. The control signal from the central controller sends commands to monitor the operation of the inverter, and the feedback signal from the inverter is connected to the central controller to make warning judgments.

[0016] (Discharge resistor)(3) Refer to Fig. 7. The inverter is involved in the power supply to the hydraulic pump motor. Sudden changes in the hydraulic pump current during startup and pump operation cause overcurrent in the power unit of the inverter. Therefore, in the present invention, in addition to the use of inverter control, it is also necessary to consider incorporating an appropriate current limiting resistor or discharge resistor into the inverter. The discharge resistor is used to limit the sudden current to the power unit of the inverter when there is a sudden current change corresponding to the torque of the hydraulic motor during operation.

[0017] (Accumulator pressure monitoring sensor)(4) Refer to Fig. 8. To monitor the accumulator pressure, the power cabinet for adjusting the power consumption of the die-casting machine and the hydraulic pump for industrial machines is integrated with a pressure measurement sensor system including a sensor signal receiver attached to the cabinet and a pressure measurement sensor head attached to the accumulator of the die-casting machine. This integrated sensor measures the hydraulic pressure of the accumulator and plays a role in feeding back to the central controller integrated in the power cabinet to adjust the power consumption of the hydraulic pumps of the die-casting machine and industrial machines. The signal from the sensor is transmitted to the central controller in analog (voltage or current) or digital form. This signal is processed by the central controller to recognize, analyze, and calculate the pressure level measured by the accumulator, and make a control decision to supply power to the hydraulic pump to operate according to the required requirements.

[0018] (Indicator light)(5) The cabinet has indicator lights showing the operating state of the system and detected faults. These indicator lights receive signals from the central controller.

[0019] (Power cabinet ventilation system with exhaust duct) It includes an exhaust duct opening 8, an exhaust duct 6, an exhaust fan, and an air filter. Refer to Fig. 9. Since the electrical equipment in the cabinet generates heat during operation, a ventilation system for cooling is required. The hot air generated in the cabinet is discharged to the external environment through the fan system, and the cold air from the external environment circulates into the cabinet through the filter system to prevent dust. The two main mechanisms for air circulation and cooling are the discharge resistor block and the inverter. The air circulation for cooling the discharge resistor is carried out by the exhaust fan and the intake air filter. The air circulation for cooling the inverter is carried out by the fan system integrated with the inverter through the inverter outlet air duct attached to the cabinet housing. The direction of the ventilation system and air circulation is shown in Fig. 9.

[0020] After being connected to the die-casting machine's control system, the power cabinet performs three main functions: controlling the operation of the hydraulic pump to conserve unnecessary energy; controlling the accumulator pressure based on feedback pressure signals; and automatically warning of system failures. See Figure 11 for an example of controlling the operation of the hydraulic pump using signals.

[0021] (Control of hydraulic pump operation) A power cabinet for adjusting the power consumption of die-casting machines and industrial machinery hydraulic pumps automatically receives signals from the die-casting machine's actuators requesting hydraulic pressure, starts the hydraulic pumps, and supplies power. Depending on the power requirements of the die-casting machine at a given time, the power cabinet for adjusting the power consumption of die-casting machines and industrial machinery hydraulic pumps automatically calculates and determines how to control the motor operation at the appropriate supply frequency according to the requirements.

[0022] When the hydraulic operating system of a die-casting machine does not require hydraulic pressure, the power cabinet, which is used to regulate the power consumption of the die-casting machine and industrial machinery hydraulic pumps, automatically stops the power supply to the hydraulic pump motor to conserve energy.

[0023] Hydraulic motors for die-casting machines exceeding 350 tons have very high output and can handle very high starting currents. The operating current changes continuously according to the short-term repeating mode. To control the motor according to the requirements of the present invention, it is necessary to integrate a suitable inverter for control. When integrating a control inverter to meet the above requirements, the type of inverter should also be considered. The selected inverter must meet the starting and operating characteristics of the hydraulic pump motor. By selecting appropriate inverter parameters and type, the motor's starting characteristics can be met, the motor's operating torque can be met without causing overcurrent during startup and long-term operation, and the motor will not overheat due to insufficient energy supply to the hydraulic pump motor.

[0024] Because hydraulic pumps operate at high torque and constantly operate under repeated overcurrents, the inverter must also meet the requirements of these load characteristics during operation. Meeting this requirement is impossible if only the inverter is involved in powering the hydraulic pump motor, as rapid changes in current during startup and pump operation would cause overcurrents in the inverter's power unit. Therefore, in addition to using inverter control, the present invention also considers integrating a suitable current-limiting resistor or discharge resistor into the inverter. A discharge resistor is used to limit the rapid current to the inverter's power unit when the current corresponding to the torque of the hydraulic motor changes rapidly during operation.

[0025] (Accumulator pressure control) The hydraulic system of a die-casting machine operates based on a system of cylinders and hydraulic valves that are automatically controlled by the system's PLC program. - Actuator system movement mechanism: Directly uses pressure and flow rate from a hydraulic pump. - Mechanism for generating pressure to compress the product: Uses pressure from an accumulator installed in the machine.

[0026] The accumulator has the function of storing pressure at a point before the "die-casting pressure generation stage." The pressure supplied to the accumulator is obtained from the pressure generated by the pump and supplied via an automatic pressure valve system.

[0027] Since the product is produced by performing work through the speed and pressure of a die-casting cylinder, the quality of the product depends on the hydraulic energy supplied to this cylinder. The die-casting pressure cylinder is supplied with hydraulic force from an accumulator via a hydraulic valve system. Therefore, monitoring the accumulator pressure is one of the challenges addressed by this invention.

[0028] To monitor accumulator pressure, power cabinets for regulating the power consumption of hydraulic pumps for die-casting machines and industrial machinery are integrated with a pressure measurement sensor system that includes a sensor signal receiver and a pressure measurement sensor head mounted on the accumulator of the die-casting machine. The role of this integrated sensor is to measure the hydraulic pressure of the accumulator and feed it back to a central controller integrated into the power cabinet to regulate the power consumption of the hydraulic pumps of the die-casting machine and industrial machinery. The signal from the sensor is transmitted to the central controller in analog (voltage or current) or digital format. This signal is processed by the central controller, which recognizes, analyzes, and calculates the pressure level measured at the accumulator and makes control decisions to supply power to the hydraulic pumps operating according to the requirements.

[0029] (Automatic system failure warning) Integrating a central controller into a power cabinet to regulate the power consumption of hydraulic pumps in die-casting machines and industrial machinery simplifies the programming of control programs, the collection of system data, and the calculation of issuing warnings during operation. The purpose of the power cabinet is to monitor system operation and provide warnings in the event of a failure.

[0030] The following warning will be set: - Device temperature warning inside the cabinet; - Inverter malfunction warnings: overload, undervoltage, overvoltage, etc. - Accumulator pressure warning.

[0031] Of the warnings mentioned above, the accumulator pressure warning is particularly important. This warning not only helps in making decisions regarding the power control of the hydraulic pump, but also helps die-casting operators infer the condition and investigate the cause of the warning. In short, this warning is involved in monitoring and diagnosing the cause of pressure problems in the hydraulic system, including the pumps and hydraulic valve systems related to the supply of pressure to the accumulator.

Claims

[Claim 1] An energy-saving electrical cabinet for hydraulic pumps in die-casting machines and industrial machinery, comprising: cabinet housing; circuit breaker and protector; central controller; inverter; discharge resistor; pressure monitoring sensor for accumulator tank; cabinet ventilation system; and indicator lights, The cabinet enclosure has: a framework and mounting surfaces for the main components, and the sides and door have appropriately sized holes for the indicator light system and cooling fan, and the door is sealed with a gasket to prevent water vapor and dust from entering the system. The circuit breaker and protector: handle the switching of power supply to the cabinet, and provide protection against overloads and short circuits in the system. The central controller operates based on a pre-programmed control program stored in the microcontroller memory, and the control program is tunable by a programmer to meet the requirements of various types of machines. The inverter operates based on parameters set to supply and regulate electrical energy to the motor of the hydraulic pump of the die-casting machine and to control it according to the requested operating mode. The discharge resistor is connected to the inverter to reduce the current load on the inverter during operation. The central controller is connected to the inverter and receives pressure feedback signals and operation requests from the die-casting machine, performs calculations, and issues control commands. The indicator light: receives a signal from the central controller and displays the operating status and warnings. The cabinet ventilation system has: an exhaust port, ducts, an exhaust fan, and an air filter for cooling electrical components, and the exhaust from the cooling fan for the inverter is sent directly from the exhaust port. The pressure monitoring sensor for the accumulator tank comprises: a signal receiver mounted on the cabinet door and a sensor head mounted on the accumulator tank of the die-casting machine, the pressure monitoring sensor converts the pressure signal into an electrical signal transmitted to the signal receiver, and the electrical signal is transmitted to the central controller to participate in system control. The pressure monitoring sensor for the accumulator tank, equipped with an energy adjustment function, automatically receives operational control signals from the applied machine in combination with feedback from the pressure sensor and supplies electrical energy to the hydraulic pump, while simultaneously stopping the supply of electrical energy to the hydraulic pump motor during cycles when the machine does not require pressure. As a result of this control process, the electrical energy supplied to the hydraulic pump is reduced and used efficiently. The pressure monitoring sensor for the accumulator tank is: During machine operation, the operation of the hydraulic pump is adjusted to maintain the required pressure and ensure that the produced products meet quality standards; The system detects pressure anomalies during machine operation and issues related warnings, thereby helping the operator diagnose a malfunction in the hydraulic system of the machine to which it is applied; It has a pressure monitoring function that is useful for this purpose, Here, the hydraulic system of the die-casting machine operates based on cylinders and hydraulic valves that are automatically controlled by the system's PLC program. The inverter is the main drive unit responsible for efficiently controlling and reducing the energy consumption of the hydraulic pump motor. The type of inverter is selected to match the load characteristics of the hydraulic pump, and its high starting torque capacity ensures stable and accurate system operation. To optimize the performance of the inverter, it is necessary to measure and appropriately set the parameters based on the actual operation of the die-casting machine. The inverter distributes energy to the hydraulic pump and is connected to the control signals and warning signals from the central controller. The control signals from the central controller issue commands and monitor the operation of the inverter. On the other hand, the feedback signal from the inverter is connected to the central controller for warning evaluation. An energy-saving electrical cabinet for hydraulic pumps in die-casting machines and industrial machinery, characterized by the following features.

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