Energy-saving electrical 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 hydraulic pump systems of die-casting machines and industrial machinery, also known as a "hydraulic pump power conditioning cabinet". [Background technology]

[0002] Die-casting machines operate based on the pressure provided by hydraulic pumps. Pressure die-casting machine technology uses hydraulic valve systems to control the automatic operation of each stage and phase of the operating cycle. To produce products that meet quality requirements after die-casting, the hydraulic system must meet factors related to the pressure and speed of the actuators operated by the hydraulic system. Considering the sequence of stages, the power consumption of the hydraulic pump can be divided into two processes. See the diagram of the operating cycle stages of a die-casting machine (Figure 10).

[0003] (Useful power supplied to the pump) Generate the workload to execute the required machine cycle, which includes the following main stages: mold closing stage; accumulator pressure filling (performed in multiple cycles interspersed between stages); mold opening stage (performed in two mold closing and mold opening cycles); and product ejection from the mold core stage (performed in two cycles of advancing and retracting the product ejection cylinder).

[0004] (wasteful power supplied to the pump) The hydraulic pump does not generate work but continues to operate. The pump consumes energy, but the pressure generated is discharged back to the oil tank without participating in the operation of the hydraulic actuator. This includes the following stages: die casting pressure generation stage (pressure obtained from the accumulator), robotic part removal from the machine stage (excluding the work generation cycle), and release agent spray stage.

[0005] Based on the above analysis, we found that the process of "wasting power supplied to the pump" is an energy-wasting process, and that technological measures should be taken to save energy without affecting the operation of the machine. Based on our expertise in industrial control equipment and in-depth knowledge of die-casting machine systems, we have researched and applied for a patent 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 can be widely applied to other factories in the industrial field. Summary of the Invention

[0006] This invention is a power cabinet for regulating the power consumption of hydraulic pumps in die casting machines and industrial machinery. The cabinet is used to control the hydraulic pumps to conserve energy during cycles when the pumps are not producing work but are still operating, wasting energy and increasing the temperature of the system and working environment.

[0007] To solve the above problems, the 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 light (see Figure 1).

[0008] After being connected to the control system of the die-casting machine, 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 faults (see Figure 2). [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 shows a power cabinet made up of major components. [Figure 2] FIG. 1 is a schematic diagram of the control connections to the die casting machine. [Figure 3] FIG. 1 is a diagram showing an overall outline of a power cabinet. [Figure 4] FIG. 1 illustrates a switching and protection device. [Figure 5] FIG. 2 illustrates a central controller. [Figure 6] FIG. [Figure 7] FIG. 2 is a diagram showing a discharge resistor block. [Figure 8] FIG. 10 illustrates an accumulator pressure monitoring sensor. [Figure 9] FIG. 1 illustrates a power cabinet ventilation system. [Figure 10] FIG. 1 illustrates the operating cycle stages of a die casting machine. [Figure 11] FIG. 1 illustrates the use of signals to control the operation of a hydraulic pump. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following description is of the best mode for carrying out the invention. This section is intended to describe the general features of the invention and is not intended to limit the invention. The scope of the invention is most clearly defined by the appended claims.

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

[0012] (electrical cabinet) See Figure 3. The electrical cabinet contains the system framework and mounting surfaces for the major components. The cabinet sides and door have 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) See Figure 4. These devices handle the switching of power and control circuits within the cabinet and provide overload and short circuit protection in the event of a fault.

[0014] (Central Controller)(1) See Figure 5. This component determines the control signals and receives feedback signals to calculate 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 and issues control commands to the variable frequency drive and receives feedback on its operation. The central controller is connected to the die casting machine by 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 of the accumulator pressure sensor, and calculates and controls the hydraulic pump to supply hydraulic pressure according to the machine setting requirements. · The central controller is connected to indicator lights to indicate operation and warn of system faults. · The central controller is connected to the temperature sensors in the cabinet and calculates and controls the cabinet's cooling ventilation fan system.

[0015] (Inverter (VFD)) (2) See Figure 6. The inverter (VFD) is the main power device that controls the power consumption of the hydraulic pump motor in the most rational way. The type of inverter is selected according to the load characteristics of the hydraulic pump and its ability to meet high starting torque, ensuring stable and accurate operation of the system. To ensure that the inverter operates properly and meets requirements, the inverter's setting parameters must also be properly 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 and monitors the operation of the inverter, and the feedback signal from the inverter is connected to the central controller for warning judgment.

[0016] (discharge resistor)(3) See Figure 7. The inverter is responsible for supplying power to the hydraulic pump motor. Sudden changes in the hydraulic pump current during startup and pump operation can cause overcurrent in the inverter's power unit. Therefore, in addition to using inverter control, the present invention also requires the incorporation of an appropriate current-limiting or discharge resistor into the inverter. The discharge resistor is used to limit sudden current flow to the inverter's power unit when there is a sudden current change corresponding to the hydraulic motor torque during operation.

[0017] (Accumulator pressure monitoring sensor) (4) See Figure 8. To monitor the accumulator pressure, a power cabinet for regulating the power consumption of hydraulic pumps for die-casting machines and industrial machinery is integrated with a pressure measurement sensor system, including a sensor signal receiver mounted on the cabinet and a pressure measurement sensor head attached to the accumulator of the die-casting machine. This integrated sensor measures the hydraulic pressure in the accumulator and provides feedback to a central controller integrated into the power cabinet to regulate the power consumption of the hydraulic pump of the die-casting machine or industrial machinery. The signal from the sensor is sent 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 in the accumulator and makes control decisions to supply power to the hydraulic pump so that it operates according to the required requirements.

[0018] (indicator light)(5) The cabinet has indicator lights that indicate the system's operating status and any detected faults. These indicator lights receive signals from a central controller.

[0019] (Power cabinet ventilation system with exhaust duct) It includes exhaust duct opening 8, exhaust duct 6, exhaust fan, and air filter. See Figure 9. The electrical equipment inside the cabinet generates heat during operation, so a ventilation system is required for cooling. The hot air generated inside the cabinet is exhausted to the outside environment through a fan system, and cool air from the outside environment is circulated into the cabinet through a filter system to prevent dust. The two main mechanisms for air circulation and cooling are the discharge resistor block and the inverter. Air circulation for cooling the discharge resistor is achieved by an exhaust fan and an intake filter. Air circulation for cooling the inverter is achieved by a fan system integrated with the inverter through an inverter outlet air duct attached to the cabinet housing. The ventilation system and air circulation direction are shown in Figure 9.

[0020] After being connected to the die-casting machine control system, the power cabinet performs three main functions: controlling the operation of the hydraulic pump to save unnecessary energy; controlling the accumulator pressure based on the feedback pressure signal; and automatically warning of system faults. See the diagram (Figure 11) for using the signal to control the operation of the hydraulic pump.

[0021] (Control of hydraulic pump operation) The power cabinet for adjusting the power consumption of hydraulic pumps for die-casting machines and industrial machinery automatically receives a signal requesting hydraulic pressure from the actuator of the die-casting machine, starts the hydraulic pump, and supplies power. According to the power requirements of the die-casting machine at a specific time, the power cabinet for adjusting the power consumption of hydraulic pumps for die-casting machines and industrial machinery automatically calculates and determines to control the operation of the motor at an appropriate supply frequency according to the requirements.

[0022] When the hydraulic operating system of the die-casting machine does not require hydraulic pressure, the power cabinet for regulating the power consumption of hydraulic pumps for die-casting machines and industrial machinery will automatically stop supplying power to the hydraulic pump motor to save energy.

[0023] Hydraulic motors for die casting machines over 350 tons have very high power output and require very high starting currents. The operating current changes continuously according to the short-term repetition mode. To control the motor according to the requirements of this invention, an appropriate inverter must be integrated for control. When integrating a control inverter to meet the above requirements, the type of inverter must also be considered. The selected inverter must meet the starting and operating characteristics of the hydraulic pump motor. Selecting the appropriate inverter parameters and type will ensure that the motor's starting characteristics are met, the motor's operating torque is met without causing overcurrent during startup and long-term operation, and the motor does not overheat due to insufficient energy supply to the hydraulic pump motor.

[0024] Because hydraulic pumps operate at high torque and are constantly subject to repeated overcurrents, inverters must also meet these load characteristics during operation. This requirement would be impossible if the inverter were solely responsible for powering the hydraulic pump motor, because sudden 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 requires the integration of an appropriate current-limiting or discharge resistor into the inverter. The discharge resistor is used to limit the sudden current flow to the inverter's power unit when the current corresponding to the hydraulic motor's torque suddenly changes during operation.

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

[0026] The accumulator serves to store pressure prior to the "die casting pressure generation phase." The pressure supply to the accumulator is taken from the pressure generated by the pump and is fed through an automatic pressure valve system.

[0027] Since the product is produced by the work done by the speed and pressure of the 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 power from an accumulator through a hydraulic valve system. Therefore, monitoring the accumulator pressure is one of the challenges addressed by this invention.

[0028] To monitor the 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, which includes a sensor signal receiver and a pressure measurement sensor head attached to the accumulator of the die-casting machine. The role of this integrated sensor is to measure the hydraulic pressure in the accumulator and provide feedback to the central controller integrated into the power cabinet to regulate the power consumption of the hydraulic pump of the die-casting machine or industrial machinery. The signal from the sensor is sent 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 in the accumulator and makes control decisions to supply power to the hydraulic pump, which operates according to the requirements.

[0029] (Automatic warning of system failure) Integrating a central controller into a power cabinet to regulate the power consumption of hydraulic pumps in die-casting machines and industrial machinery makes it easier to program the control program, collect system data, and issue warnings during operation. The purpose of the power cabinet is to monitor the operation of the system and provide warnings in case of faults.

[0030] The following warnings are set: - Device temperature warning in cabinet; - Inverter fault warning: overload, low voltage, high voltage, etc.; - Accumulator pressure warning.

[0031] Among the above warnings, the accumulator pressure warning is very important. This warning not only helps to make decisions regarding the power control of the hydraulic pump, but also helps the die casting operator to deduce the condition and investigate the cause of the warning. In other words, this warning is involved in monitoring and diagnosing the cause of pressure failure in the hydraulic system, including the pump and hydraulic valve system related to the pressure supply to the accumulator.

Claims

[Claim 1] An energy-saving electrical cabinet for hydraulic pumps of die-casting machines and industrial machinery, comprising: a cabinet housing; a circuit breaker and protector; a central controller; an inverter; a discharge resistor; a pressure monitoring sensor for an accumulator tank; a cabinet ventilation system; and an indicator light; The cabinet enclosure has: a framework and mounting surfaces for the major components, and appropriately sized holes in the sides and door for an indicator light system and cooling fans, the door being sealed with a gasket to prevent water vapor and dust from entering the system; The circuit breaker and protector: handles switching of power supply to the cabinet and provides overload and short circuit protection within the system; The central controller: operates on the basis of a pre-programmed control program stored in a microcontroller memory, the control program being adjustable by a programmer to suit the requirements of different types of machines; The inverter: supplies and regulates electrical energy to the motor of the hydraulic pump of the die casting machine, and operates based on set parameters to control it according to a required 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 signals from the central controller to display the operating status and warning; The cabinet ventilation system has an exhaust port, a duct, an exhaust fan, and an air filter for cooling electrical components, and exhaust from the cooling fan for the inverter is directly sent through the exhaust port; The pressure monitoring sensor for the accumulator tank has a signal receiver attached to a cabinet door and a sensor head attached to the accumulator tank of the die casting machine, the pressure monitoring sensor converts a pressure signal into an electrical signal that is sent to the signal receiver, and the electrical signal is sent to the central controller for participating in system control; The pressure monitoring sensor for the accumulator tank with energy regulation function: automatically receives an operation control signal from the applied machine in combination with feedback from the pressure sensor to supply electrical energy to the hydraulic pump, and at the same time stops supplying electrical energy to the hydraulic pump motor during cycles when the machine does not require pressure, and 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 comprises: Regulating the operation of hydraulic pumps while the machine is in operation to maintain the required pressure and ensure that the produced products meet quality standards; Detecting pressure abnormalities during machine operation and issuing relevant warnings to help operators diagnose faults in the hydraulic system of said applied machine; It has a pressure monitoring function that is particularly useful, wherein 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 driving device responsible for efficiently controlling and reducing the energy consumption of the hydraulic pump motor. The inverter type is selected according to 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, the parameters need to be measured and set appropriately based on the actual operation of the die casting machine; the inverter delivers energy to the hydraulic pump and is connected to control and warning signals from the central controller; Control signals from the central controller issue commands and monitor operation of the inverter; Meanwhile, a feedback signal from the inverter is connected to the central controller for warning evaluation. This energy-saving electrical cabinet is for hydraulic pumps in die-casting machines and industrial machinery.

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