Energy-saving electrical cabinet for hydraulic pump in die-casting machines and industrial machinery

Abstract

The invention relates to a power regulation cabinet for hydraulic pumps in die casting machines and industrial equipment, including: the cabinet enclosure, circuit breakers and protectors, central controller, inverter, discharge resistor, pressure monitoring sensors for the accumulator tank, cabinet ventilation system, and indicator lights. After being connected to the control circuit system of the die casting machine, it performs three main functions: Controlling the operation of the hydraulic pump; Regulating the accumulator tank pressure based on feedback pressure signals, and the Automatically warning of any 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 PTC program.

Description

[0001] ENERGY-SAVING ELECTRICAL CABINET FOR HYDRAULIC PUMP IN DIE-CASTING MACHINES AND INDUSTRIAL MACHINERY

[0002] Technical Field of the Invention

[0003] The invention relates to a power cabinet, specifically an energy-saving power cabinet for the hydraulic pump system of die casting machines and industrial machinery, also known as the "Hydraulic Pump Power Regulating Cabinet".

[0004] Technical Status of the Invention

[0005] Die casting machines operate based on the pressure provided by hydraulic pumps. Pressure die-casting machine technology uses a hydraulic valve system to control the automatic operation of each stage and phase in an operating cycle. To produce products that meet quality requirements after casting, the hydraulic system must ensure that it meets the 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. Diagram of the operating cycle stages of the die casting machine (Figure 10).

[0006] Useful electrical power supplied to the pump: Generates work to perform the required machine cycles, including the main stages: mold closing stage, accumulator pressure filling (performed with multiple cycles interspersed with the stages), mold opening stage (performed with two molds closing and opening cycles), product ejection stage from the mold core (performed with two cycles of the product ejection cylinder advancing and retracting).

[0007] Useless electrical power supplied to the pump: The hydraulic pump does not generate work but still operates. The pump consumes energy, but the pressure generated is discharged back to the oil tank without participating in the operation of the hydraulic actuators. Includes the stages: casting pressure generation stage (pressure taken from the accumulator), robot product removal stage from the machine (excluding work-generating cycles), mold release agent spraying stage.

[0008] Based on the above analysis, it is observed that the process of "useless electrical power supplied to the pump" is a process that wastes energy, and technical measures need to 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 proposed a patent for a power cabinet for regulating power consumption for hydraulic pumps in die casting machines and industrial machinery to save energy in production and apply it extensively in other factories in the industrial field.

[0009] Technical Nature of the Invention

[0010] The invention is a power cabinet for regulating power consumption for hydraulic pumps in die casting machines and industrial machinery. The cabinet is used to control the hydraulic pump to save energy during cycles when the pump is not generating work but is still operating, which wastes energy and increases the temperature of the system and the working environment.

[0011] To solve the above problems, the power cabinet for regulating power consumption for hydraulic pumps in die casting machines and industrial machinery is composed 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 (Figure 1).

[0012] After being connected to the control system of the die casting machine, the power cabinet will perform three main functions: Control the operation of the hydraulic pump, Control the accumulator pressure based on the feedback pressure signal, and Automatically warn of faults in the system (Figure 2) Brief Description of Illustrations

[0013] Figure 1 : Power cabinet composed of main parts

[0014] Figure 2: Schematic diagram of control connection with die casting machine

[0015] Figure 3: General overview of the power cabinet

[0016] Figure 4: Switching and protection devices

[0017] Figure 5: Central controller

[0018] Figure 6: Inverter

[0019] Figure 7: Discharge resistor block

[0020] Figure 8: Accumulator pressure monitoring sensor

[0021] Figure 9: Power cabinet ventilation system

[0022] Figure 10: Diagram of the operating cycle stages of the die casting machine

[0023] Figure 11 : Diagram showing the use of signals to control the operation of the hydraulic pump

[0024] Detailed Description of the Invention

[0025] The following description is the best method to implement the invention. This section is intended to illustrate 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 accompanying claims.

[0026] Refer to Figure 1. The power cabinet for regulating power consumption for hydraulic pumps in die casting machines and industrial machinery in the invention includes the following parts: 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 Lights 5. Details:

[0027] Electrical Cabinet: Refer to Figure 3. The electrical cabinet includes the system framework and the mounting surface for the main components. Appropriate holes are made on the sides and door of the cabinet for indicator lights and cooling fans. The cabinet door is sealed with gaskets to prevent water vapor and dust from entering the system.

[0028] Circuit Breakers and Protectors (7): Refer to Figure 4. These devices handle the switching of power and control circuits within the cabinet, providing protection against overloads and short circuits when faults occur.

[0029] Central Controller (1): Refer to Figure 5. This component decides the control signals and receives feedback signals to calculate control and system alerts. Features include:

[0030] • The central controller is programmed with a control program according to the operating requirements of the die casting machine cycles.

[0031] • Hie central controller is connected by signal to the variable frequency drive to issue control commands to the variable frequency drive and receive feedback on its operation.

[0032] • The central controller is connected by signal to the die casting machine to receive the signal requesting power supply to the hydraulic pump, in order to operate in response to the machine cycles.

[0033] • The central controller is connected to the feedback signal of the pressure sensor of the accumulator to calculate and control the hydraulic pump to supply hydraulic pressure according to the setting requirements of the machine.

[0034] • The central controller is connected to the indicator lights to indicate operation and warn of faults in the system.

[0035] • The central controller is connected to the temperature sensors in the cabinet to calculate and control the cabinet cooling ventilation fan system.

[0036] Inverter (VFD) (2): Refer to Figure 6. The inverter (VFD) is the main power device responsible for controlling 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 its ability to meet high starting torque to ensure stable and accurate operation of the system. For the inverter to operate well and meet the requirements, the setting parameters for the inverter must also be measured and calculated appropriately based on the actual operation of the die casting machine. The inverter is the power device to distribute power to the hydraulic pump and is connected to the central controller for control and warning signals. The control signal from the central controller will send commands and monitor the operation of the inverter, and the feedback signal from the inverter will be connected to the central controller to make warning judgments.

[0037] Discharge Resistor (3): Refer to Figure 7. The inverter participates in the operation of supplying power to the hydraulic pump motor. The sudden change in hydraulic pump current during startup and during pump operation will cause an overcurrent to the power unit of the inverter. Therefore, in addition to using the inverter control, the invention also needs to consider integrating a suitable 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 hydraulic motor torque during operation.

[0038] Accumulator Pressure Monitoring Sensor (4): Refer to Figure 8. In order to monitor the accumulator pressure, the power cabinet for regulating the power consumption of the hydraulic pump 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 mounted on the accumulator of the die casting machine. This integrated sensor has the task of measuring the hydraulic pressure of the accumulator and feeding back to the central controller integrated in the power cabinet for regulating the power consumption of the hydraulic pump for die casting machines and industrial machinery. The signal from the sensor is transmitted to the central controller in analog (voltage or current) or digital form. This signal will be processed by the central controller to recognize the pressure level measured on the accumulator for analysis and calculation to make a control decision on supplying power to the hydraulic pump to operate in accordance with the required requirements.

[0039] Indicator Lights (5): There are indicator lights on the cabinet to indicate the operating status of the system and any detected faults. These indicator lights receive signals from the central controller.

[0040] Power Cabinet Ventilation System with Exhaust Duct: Including exhaust duct opening 8 and exhaust duct 6, exhaust fan and air filter. Refer to Figure 9. The electrical equipment in the cabinet will generate heat during operation and require a ventilation system for cooling. The hot air generated in the cabinet is discharged to the outside environment through the fan system, and the cold air from the outside environment is circulated into the cabinet through the filtration 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 done by an exhaust fan and an air inlet filter. The air circulation for cooling the inverter is done by a fan system integrated with the inverter through the inverter outlet air duct mounted on the cabinet housing. The ventilation system and air circulation direction are described in Figure 9.

[0041] After being connected to the control system of the die casting machine, the power cabinet will perform three main functions: Control the operation of the hydraulic pump to save unnecessary energy; Control the accumulator pressure based on the feedback pressure signal; Automatically warn of faults in the system. Diagram showing the use of signals to control the operation of the hydraulic pump (Figure 11).

[0042] • Control of the hydraulic pump operation:

[0043] The power cabinet for regulating the power consumption of the hydraulic pump for die casting machines and industrial machinery will automatically receive a signal requesting hydraulic pressure from the actuators on the die casting machine to start and supply power to the hydraulic pump. Depending on the power requirement of the die casting machine at any given time, the power cabinet for regulating the power consumption of the hydraulic pump for die casting machines and industrial machinery will automatically calculate and decide to control the operation of the motor with the appropriate supply frequency according to the requirement.

[0044] When the hydraulic actuation system of the die casting machine does not require hydraulic pressure, the power cabinet for regulating the power consumption of the hydraulic pump for die casting machines and industrial machinery will automatically stop supplying power to the hydraulic pump motor to save energy at this time.

[0045] Hydraulic motors for die casting machines of 350 tons or more have very high power, corresponding to very high starting currents. The operating current changes continuously according to a short-term repeating mode. In order to control the motor according to the invention's requirements, a suitable inverter needs to be integrated for control. When integrating the control inverter to meet the above requirements, the type of inverter is also a matter to be considered. The selected inverter must meet the starting and working characteristics of the hydraulic pump motor. Choosing the right inverter parameters and type will help to meet the starting characteristics of the motor, meet the working torque of the motor without causing overcurrent during startup and long-term operation, as well as generating motor heat due to insufficient energy supply to the hydraulic pump motor.

[0046] Due to the load characteristics of the hydraulic pump operating with high torque and always operating with repetitive overcurrent, the inverter must also meet the requirements of this load characteristic when operating. To meet this requirement, if only the inverter participates in the power supply for the hydraulic pump motor, it is not possible because the sudden change in current during startup and during pump operation will cause an overcurrent to the power unit of the inverter. Therefore, in addition to using the inverter control, the invention also needs to consider integrating a suitable 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 change in current corresponding to the hydraulic motor torque during operation.

[0047] • Accumulator pressure control:

[0048] The hydraulic system of the die casting machine operates based on a system of cylinders and hydraulic valves that are automatically controlled by the PLC program of the system.

[0049] Moving mechanisms of the actuator system: Use the pressure and flow directly from the hydraulic pump.

[0050] Mechanisms to create pressure to compress the product: Use the pressure from the accumulator located on the machine.

[0051] The accumulator has the function of storing pressure at the time before the "casting pressure creation stage". The pressure supply to the accumulator is taken from the pressure generated by the pump and supplied through the automatic pressure valve system. Since the product is created by performing work by the speed and pressure of the casting cylinder, the product quality depends on the hydraulic energy supplied to this cylinder. The casting pressure cylinder is supplied with hydraulic power from the accumulator through the hydraulic valve system. Therefore, monitoring the accumulator pressure is one of the issues that the invention addresses.

[0052] To monitor the accumulator pressure, the power cabinet for regulating the power consumption of the hydraulic pump for die casting machines and industrial machinery is integrated with a pressure measurement sensor system, including a sensor signal receiver mounted on the same and a pressure measurement sensor head mounted on the accumulator of the die casting machine. This integrated sensor has the task of measuring the hydraulic pressure of the accumulator and feeding back to the central controller integrated in the power cabinet for regulating the power consumption of the hydraulic pump for die casting machines and industrial machinery. The signal from the sensor is transmitted to the central controller in analog (voltage or current) or digital form. This signal will be processed by the central controller to recognize the pressure level measured on the accumulator for analysis and calculation to make a control decision on supplying power to the hydraulic pump to operate in accordance with requirements.

[0053] • Automatic warning of faults in the system

[0054] The integration of the central controller in the power cabinet for regulating the power consumption of the hydraulic pump for die casting machines and industrial machinery will make it easier to program the control program, collect system data and calculate to issue warnings during operation. The purpose of the power cabinet is to monitor the operation of the system and provide warnings in case of any faults. Hie following warnings are set up:

[0055] - Device temperature warning in the cabinet;

[0056] - Inverter fault warnings: overload, low voltage, high voltage, etc.;

[0057] - Accumulator pressure warning.

[0058] Among the above warnings, the accumulator pressure warning is of great importance. In addition to making decisions about hydraulic pump power control, this warning also helps the die casting operator to guess the status and investigate the cause of the warning. In other words, this warning participates in the monitoring and diagnosis of the cause of pressure faults in the hydraulic system, including the pump and the hydraulic valve system related to supplying pressure to the accumulator.

Claims

PROTECTION REQUIREMENTS1. Energy-Saving Electrical Cabinet For Hydraulic Pump In Die-Casting Machines And Industrial Machinery includes: the cabinet enclosure, circuit breakers and protectors, central controller, inverter, discharge resistor, pressure monitoring sensors for the accumulator tank, cabinet ventilation system, and indicator lights; specifically:Cabinet Enclosure: Includes a framework and mounting surface for the main components. The sides and door have appropriately sized holes for the indicator light system and cooling fans. The door is sealed with gaskets to prevent water vapor and dust from entering the system.Circuit Breakers and Protectors: Handle the switching of power supply to the cabinet and provide overload and short circuit protection within the system.Central Controller: Operates based on a pre-programmed control program stored in the microcontroller memory. The control program can be adjusted by the programmer to meet the requirements of different types of machines.Inverter: Supplies and regulates electrical energy to the hydraulic pump motor of the die casting machine. It operates based on parameters set to control according to the required operating mode.Discharge Resistor: Connected to the inverter to help reduce the current load on the inverter during operation. The central controller is connected to the inverter, receiving pressure feedback signals and operational requests from the die casting machine to calculate and issue control commands.Indicator Lights: Receive signals from the central controller to display operating statuses and alerts.Cabinet Ventilation System: Includes exhaust vents, ducts, extraction fans, and air filters to cool the electrical components. The cooling fan exhaust for the inverter is directly routed through the exhaust vent;Pressure Monitoring Sensors for the Accumulator Tank: Includes a signal receiver installed on the cabinet door and a sensor head mounted on the accumulator tank of the die casting machine. It converts pressure signals into electrical signals sent to the signal receiver. These signals are transmitted to the central controller to participate in system control;Pressure monitoring sensor for the accumulator tank with energy regulation function: Automatically receives operational control signals from the applied machine, combined with feedback from the pressure sensor, to supply electrical energy to the hydraulic pump; simultaneously stops supplying electrical energy to the hydraulic pump motor during cycles when the machine does not require pressure; the result of this control process is the reduction and efficient use of electrical energy supplied to the hydraulic pump.The accumulator pressure monitoring sensor has a pressure monitoring function that helps to:Regulate the operation of the hydraulic pump to maintain the desired pressure during machine operation, ensuring the produced product meets quality standards; detects pressure abnormalities during machine operation to issue related warnings, assisting the operator in diagnosing faults in the hydraulic system of the applied machinery; 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.The inverter is the main driving device, 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, with a high starting torque capacity to ensure stable and precise system operation. For optimal inverter performance, the parameters must be measured and appropriately set based on the actual operation of the die casting machine. The inverter distributes energy to the hydraulic pump and is connected to the control and warning signals from the central controller. Control signals from the central controller issue commands and monitor the inverter's operation, while feedback signals from the inverter connect back to the central controller for warning assessments.

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