A hydraulic press frequency conversion energy-saving optimization system and optimization method

Abstract

The present invention provides a frequency conversion energy-saving optimization system and method for a hydraulic press, comprising a frequency converter, a metronome, and a frequency conversion optimization device. The metronome is electrically connected to the frequency conversion optimization device, configured to detect operating tempos at different frequencies and transmit the frequencies and corresponding operating tempos to the frequency conversion optimization device. The frequency conversion optimization device is communicatively connected to the frequency converter, configured to send control instructions to the frequency converter based on the operating tempo and frequency. The frequency converter receives the control instructions and controls the output frequency. This invention solves the problem of frequency conversion equipment only adjusting the hydraulic press's output power to the minimum when it is hovering to achieve energy savings, and solves the problem of product backlogs caused by different operating hours.

Description

Technical Field

[0001] The present invention relates to the technical field of energy-saving equipment, and in particular to a frequency conversion energy-saving optimization system and an optimization method for a hydraulic press. Background Art

[0002] Stamping companies need multiple steps to produce a product, and each step requires at least one hydraulic device as a production tool to stamp the product. Hydraulic equipment is a high-power device with an operating power ranging from 30 to 200 kW. The process of stamping products with hydraulic equipment includes four steps: hovering, descending, pressing, and ascending. The hovering action does not require the motor to drive the hydraulic arm to move, and the motor is not working at full capacity at this time. The other actions require the motor to drive the hydraulic arm to move, and the motor is working at full capacity at this time. For a product, multiple hydraulic devices are required to stamp it. The duration of the pressing action of each hydraulic device is different. If no energy-saving device is installed, each hydraulic device will work at full capacity. During the ascending, pressing, and descending processes, due to the different working times, some hydraulic devices will accumulate products and some hydraulic devices will be idle, resulting in a large amount of energy waste. The existing technology adjusts the motor output power by adding a frequency converter to each hydraulic device. However, the output power of the hydraulic press is usually only adjusted to the minimum when hovering to achieve energy saving. At the same time, after changing to other products that need to be stamped, each device needs to be manually adjusted separately, which wastes manpower. Summary of the Invention

[0003] In response to the shortcomings of the existing technology, the present invention provides a hydraulic press frequency conversion energy-saving optimization system and optimization method, which solves the problem that the frequency conversion equipment in the existing technology only adjusts the output power of the hydraulic press to the minimum when it is hovering to achieve energy saving, and the problem of product backlog due to different working hours.

[0004] According to an embodiment of the present invention, a hydraulic press frequency conversion energy-saving optimization system device includes a frequency converter, a metronome and a frequency conversion optimization device. The metronome is electrically connected to the frequency conversion optimization device for detecting the working rhythm at different frequencies and transmitting the frequency and the corresponding working rhythm to the frequency conversion optimization device. The frequency conversion optimization device is communicatively connected to the frequency converter for sending control instructions to the frequency converter according to the working rhythm and frequency. The frequency converter is used to receive the control instructions and control the output frequency.

[0005] Preferably, the frequency conversion optimization device includes a frequency conversion control module, a frequency conversion optimization module and a beat knowledge base module electrically connected in sequence, the frequency conversion control module is communicatively connected to the frequency converter, and the beat knowledge base module is electrically connected to the metronome and the frequency converter.

[0006] Preferably, the metronome includes a first relay, a second relay and a timer, the first relay and the second relay are both electrically connected to the timer, and the timer is electrically connected to the beat knowledge base module.

[0007] On the other hand, according to an embodiment of the present invention, a method for optimizing frequency conversion energy saving of a hydraulic press is also provided, which comprises the following steps: S1: installing a frequency converter and a metronome on all hydraulic presses on the same production line;

[0008] S2: Do not place the product for air compression testing. Manually input different test frequencies into the frequency conversion optimization module multiple times, and send the test frequencies to the frequency conversion control module and the beat knowledge base module respectively. The frequency conversion control module sends control instructions to the frequency converter, allowing the frequency converter to control the operation of the hydraulic press at different test frequencies. The metronome collects the working beat of the hydraulic press at different test frequencies and sends the working beat to the beat knowledge base module to generate the corresponding test frequency-time diagram.

[0009] S3: The product process information is passed into the frequency conversion optimization module. The frequency conversion optimization module calculates the optimal frequency solution based on the product process and the test frequency-time diagram. The frequency conversion control module sends control instructions to the frequency converter according to the optimal frequency solution. The frequency converter controls the hydraulic press to operate at the optimal frequency according to the control instructions, so that the maximum working time of all hydraulic presses is the same.

[0010] Preferably, the initial test frequency input to the frequency conversion optimization module is 10 Hz, and then the frequency is continuously input at an increase rate of 1 Hz at intervals of 1 minute until the frequency is equal to 50 Hz.

[0011] Preferably, the method for obtaining the optimal frequency solution includes: for any hydraulic press, keeping the die pressing time and the maximum working time unchanged, dividing the difference between the maximum working time and the die pressing time into two parts, obtaining the optimal downlink time and the optimal return time, then querying the test frequency-time graph to obtain the optimal downlink frequency and the optimal return frequency corresponding to the optimal downlink time and the optimal return time, and then combining the optimal downlink frequency, the optimal return frequency and the die pressing frequency into the optimal frequency solution;

[0012] The optimal downlink time and the optimal return time are respectively greater than the minimum downlink time and the minimum return time.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] A frequency converter and metronome are installed for all hydraulic presses on the same production line. Different test frequencies are manually input into the frequency conversion optimization device, and the frequency converter controls the operation of each hydraulic press at different frequencies. At this time, the metronome collects the working rhythm of each hydraulic press at different frequencies and transmits it to the frequency conversion optimization device to form a corresponding test frequency-time diagram. Then, based on the product process information, the optimal frequency solution is generated to ensure that all hydraulic presses take exactly the same time to complete a stamping. Under the premise of ensuring normal stamping products, the output frequency of each step of each hydraulic press is reduced to reduce energy consumption and achieve better energy-saving effects. At the same time, the working time is extended so that all hydraulic presses take exactly the same time to complete a stamping, which can solve the problem of product backlogs at some hydraulic presses. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 2 is a system structure diagram of an embodiment of the present invention.

[0016] Figure 2 This is an optimization flow chart of an embodiment of the present invention.

[0017] Figure 3 This is a test frequency-downlink time diagram of an embodiment of the present invention.

[0018] In the above drawings: frequency conversion control module 1, frequency conversion optimization module 2, beat knowledge base module 3, timer 4, first relay 5, second relay 6, hydraulic press 7, frequency converter 8. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0020] like Figure 1 As shown, an embodiment of the present invention proposes a frequency conversion energy-saving optimization system device for a hydraulic press 7, including multiple frequency converters 8, multiple metronomes and frequency conversion optimization devices. Multiple hydraulic presses 7 are arranged on the same production line. Any product to be stamped needs to be stamped once in sequence by all the hydraulic presses 7 on the production line. Therefore, a frequency converter 8 and a metronome will be installed on each hydraulic press 7.

[0021] The frequency conversion optimization device is mainly used for remotely controlling the frequency converter 8 and generating the optimal frequency scheme, and includes a frequency conversion control module 1, a frequency conversion optimization module 2 and a beat knowledge base module 3 electrically connected in sequence. The frequency conversion control module 1 is communicatively connected to the frequency converter 8, and the chip built into the frequency conversion control module 1 uses the RS485 communication protocol to communicate with the frequency converter 8.

[0022] The working process of the hydraulic press 7 includes four motion processes: hovering, descending, pressing, and returning. Therefore, the working beat includes the hovering time, descending time, pressing time, and returning time corresponding to the above four motion processes. The metronome includes a first relay 5, a second relay 6, and a timer 4. The first relay 5 and the second relay 6 are both electrically connected to the timer 4, and the timer 4 is electrically connected to the beat knowledge base module 3.

[0023] When the hydraulic arm of the hydraulic press 7 starts to move downward, the first relay 5 is turned on. When the hydraulic arm touches the product, the second relay 6 is turned on. This process is called the downward process, and the time required for this process is the downward time.

[0024] From the start of molding to the completion of molding and when the hydraulic arm just leaves the product, the second relay 6 is closed. This process is the molding process, and the time required for this process is the molding time.

[0025] When the hydraulic arm continues to move upward and returns to the initial position, the first relay 5 is closed. This process is called the return process, and the time required for this process is the return time.

[0026] Different hydraulic presses 7 have different corresponding downtimes, die pressing times and return times. Therefore, after recording the downtime, die pressing time and return time, the timer 4 sends them to the beat knowledge base module 3. The beat knowledge base module 3 generates a test frequency-downtime diagram and a test frequency-return time diagram according to different test frequencies and corresponding downtime and return time. Then, in the actual stamping process, according to the die pressing time and maximum working time required by the product process information and compared with the test frequency-downtime diagram and the test frequency-return time, the optimal downtime frequency, return frequency and die pressing frequency are obtained, and the frequency converter 8 is controlled by the frequency conversion control module 1 to control the operation of the hydraulic press 7 according to the optimal frequency, and the frequencies of the downtime and return processes are lowered to extend the operating time of the downtime and return processes, so as to reduce energy consumption and achieve better energy saving. At the same time, the working time is extended so that the time for all hydraulic presses 7 to complete a stamping is exactly the same, which can solve the problem of product backlog at some hydraulic presses 7.

[0027] On the other hand, the embodiment of the present invention also provides a hydraulic press frequency conversion energy saving optimization method, such as Figure 2 As shown, it includes the following steps:

[0028] S1: A frequency converter and metronome are installed on all hydraulic presses on the same production line;

[0029] The same product often needs to be stamped multiple times before it can be formed. Therefore, there will be multiple hydraulic presses on the same production line. Any product to be stamped needs to be stamped once in sequence by all the hydraulic presses on the production line. Therefore, a frequency converter and metronome will be installed on each hydraulic press. At the same time, the working process of the hydraulic press includes four processes: descending, die pressing, returning and hovering.

[0030] S2: Do not place the product for air pressure test;

[0031] Manually input different test frequencies into the frequency conversion optimization module multiple times, starting from the initial frequency of 10Hz, and continuously input at intervals of 1 minute and at a growth rate of 1Hz (that is, input a test frequency of 11Hz after 1 minute, input a test frequency of 12Hz after 2 minutes, and so on). At the same time, after inputting the test frequency, the frequency conversion optimization module immediately sends the test frequency to the frequency conversion control module and the beat knowledge base module respectively. The frequency conversion control module sends control instructions to the frequency converter, allowing the frequency converter to control the operation of the hydraulic press at different test frequencies. The metronome collects the working beat of the hydraulic press at different test frequencies and sends the working beat to the beat knowledge base module to generate the corresponding test frequency-time diagram.

[0032] The working cycle includes the running time of the hydraulic press's hovering, descending, die pressing and return processes. Therefore, when the die pressing arm of the hydraulic press begins to descend, the switch of the first relay is toggled to the "on" state. At this time, the first relay starts to continuously send electrical signals to the timer, and the timer starts timing.

[0033] When the lower side of the die arm of the hydraulic press just touches the surface of the product, the switch of the second relay will be toggled, making the second relay in the "on" state. At this time, the second relay starts to continuously send signal pulses to the timer, and the timer ends the timing. The timing time is transmitted as the downlink time to the beat knowledge base module for storage, and then the timer is reset to zero and starts timing again;

[0034] When the stamping is completed, the die arm of the hydraulic press moves up. When the die arm just leaves the product, the second relay switch is toggled to the "off" state. At this time, the second relay no longer sends an electrical signal to the timer, and the timer ends timing. The timing time is transmitted to the beat knowledge base module as the die pressing time for storage, and then the timer is reset to zero and counts again;

[0035] When the die arm of the hydraulic press returns to its original position completely, the entire stamping process ends and the switch of the first relay is toggled to the "off" state. At this time, the first relay no longer sends an electrical signal to the timer, and the timer ends timing. The timing time is transmitted as the return time to the beat knowledge base module for storage. Then, according to different test frequencies and the corresponding downtime and return time, the test frequency-downtime diagram is generated respectively (such as Figure 3) and the test frequency-return time diagram (which is the same as Figure 3 In addition, since the models and finished product processes of all hydraulic presses may not be exactly the same and there are more or less some differences, a separate test frequency-downward time graph and test frequency-return time graph will be generated for each hydraulic press.

[0036] Figure 3 In the figure, the horizontal axis is the downlink time, and the vertical axis is the Hz value. Figure 3 It can be seen that as the time required for the downward process of the hydraulic press decreases, the frequency increases continuously and presents a linear distribution.

[0037] S3: The product process information is passed into the frequency conversion optimization module. The frequency conversion optimization module calls the test frequency-time diagram based on the product process information to calculate the optimal frequency solution. The frequency conversion control module sends control instructions to the frequency converter based on the optimal frequency solution. The frequency converter controls the hydraulic press to operate at the optimal frequency based on the control instructions, so that the maximum working time of all hydraulic presses is the same.

[0038] The product process information includes but is not limited to the minimum descending time, minimum return time, die pressing time, die pressing frequency and hovering frequency of each hydraulic press during operation, as well as the maximum working time. Since other product process information is not relevant to this technical solution, it is not described here. In this embodiment, without the interference of artificial frequency, the production of a workpiece requires four hydraulic presses in a line. The four devices are numbered from left to right as device No. 1, device No. 2, device No. 3 and device No. 4. The minimum descending time, die pressing time, minimum return time, die pressing frequency and hovering frequency of the four devices to complete one stamping are respectively:

[0039] The minimum downlink time of device No. 1 is 3s, the compression time is 5s, the minimum return time is 3s, the compression frequency is 50Hz, and the hovering frequency is 5Hz;

[0040] The minimum downlink time of device No. 2 is 3s, the compression time is 14s, the minimum return time is 3s, the compression frequency is 50Hz, and the hovering frequency is 5Hz;

[0041] The minimum downlink time of device 3 is 3s, the compression time is 7s, the minimum return time is 3s, the compression frequency is 50Hz, and the hovering frequency is 5Hz;

[0042] The minimum downlink time of device 4 is 3s, the compression time is 8s, the minimum return time is 3s, the compression frequency is 50Hz, and the hovering frequency is 5Hz;

[0043] At the same time, the maximum working time is set to 20S. In order to ensure the stamping effect, the die pressing time and die pressing frequency are fixed. At the same time, when hovering, the hydraulic press hardly works, so the hovering frequency will be adjusted to the minimum value allowed and will not be completely closed.

[0044] At this time, the total time used by device No. 1 for the downlink and return actions is 20-5=15s. By default, 20s will be evenly distributed to the two actions. Then, the frequency conversion optimization module calls the test frequency-downlink time diagram and the test frequency-return time diagram in the beat knowledge base module. According to the corresponding relationship in the diagram, the optimal frequencies of the downlink and return can be obtained. However, since decimal points may appear after the time is evenly divided, it is not convenient for process planning. Therefore, the working time will be kept as an integer. At the same time, the downlink time is relatively large to ensure the safety of manual loading. At this time, the time of the downlink and return actions can be distributed to 8s and 7s respectively. The corresponding optimal downlink frequency and optimal return frequency are 38Hz and 40Hz respectively.

[0045] Similarly, the total time used by device 2 for downlink and return is 20-14=6s. The downlink and return times are 3s and 3s respectively, and the corresponding optimal downlink and return frequencies are 46Hz and 46Hz respectively.

[0046] The downlink and return times of device 3 are 7s and 6s respectively, and the corresponding optimal downlink and return frequencies are 40Hz and 42Hz respectively;

[0047] The downlink and return times of device No. 4 are 6s and 6s respectively, and the corresponding optimal downlink frequency and optimal return frequency are 42Hz and 42Hz respectively.

[0048] Then the optimal downlink frequency, optimal return frequency, die pressing frequency and hovering frequency of devices 1-4 are integrated into the optimal frequency scheme and sent to the frequency conversion control module. The frequency conversion control module sends the optimal frequency scheme to the frequency converter through the RS485 communication protocol. The frequency converter controls the motor operation of the hydraulic press according to the optimal frequency scheme, so that it operates according to the optimal frequency scheme during the downlink, die pressing, return and hovering processes.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A hydraulic press frequency conversion energy-saving optimization system, characterized by: It includes a frequency converter, a metronome and a frequency conversion optimization device. The metronome is electrically connected to the frequency conversion optimization device and is used to detect the working beat at different frequencies and transmit the frequency and the corresponding working beat to the frequency conversion optimization device. The frequency conversion optimization device is communicatively connected to the frequency converter and is used to send control instructions to the frequency converter according to the working beat and frequency. The frequency converter is used to receive the control instructions and control the output frequency; The frequency conversion optimization device includes a frequency conversion control module, a frequency conversion optimization module and a beat knowledge base module which are electrically connected in sequence. The frequency conversion control module is communicatively connected to the frequency converter, and the beat knowledge base module is electrically connected to the metronome and the frequency converter.

2. The hydraulic press frequency conversion energy-saving optimization system according to claim 1, characterized in that: The metronome includes a first relay, a second relay and a timer, the first relay and the second relay are both electrically connected to the timer, and the timer is electrically connected to the beat knowledge base module.

3. The hydraulic press frequency conversion energy-saving optimization system according to claim 1, characterized in that: The working cycle includes hovering time, descending time, die pressing time and return time.

4. A variable frequency energy-saving optimization method for a hydraulic press, using the optimization system according to claim 1 or 2, characterized in that: include: S1: A frequency converter and metronome are installed on all hydraulic presses on the same production line; S2: Perform an air pressure test without placing any product. Manually input different test frequencies into the frequency conversion optimization module multiple times and send these frequencies to the frequency conversion control module and the beat knowledge base module. The frequency conversion control module sends control instructions to the frequency converter, allowing the frequency converter to control the hydraulic press at different test frequencies. The metronome collects the working beats of the hydraulic press at different test frequencies and sends them to the beat knowledge base module to generate the corresponding test frequency-time graph. S3: The product process information is passed into the frequency conversion optimization module. The frequency conversion optimization module calculates the optimal frequency solution based on the product process and the test frequency-time diagram. The frequency conversion control module sends control instructions to the frequency converter according to the optimal frequency solution. The frequency converter controls the hydraulic press to operate at the optimal frequency according to the control instructions, so that the maximum working time of all hydraulic presses is the same.

5. The method for optimizing frequency conversion and energy saving of a hydraulic press according to claim 4, characterized in that: The method of manually inputting different test frequencies into the frequency conversion optimization module multiple times in S2 includes: The initial test frequency input to the frequency conversion optimization module is 10 Hz, and then it is continuously input at an increase rate of 1 Hz at an interval of 1 minute until the frequency reaches 50 Hz.

6. The method for optimizing frequency conversion and energy saving of a hydraulic press according to claim 4, characterized in that: The product process information includes the minimum downward time, minimum return time, die pressing time, die pressing frequency and hovering frequency of each hydraulic press during operation, as well as the maximum working time. The maximum working time is greater than the sum of the minimum downward time, minimum return time and die pressing time of any hydraulic press.

7. The method for optimizing frequency conversion and energy saving of a hydraulic press according to claim 6, characterized in that: The method for obtaining the optimal frequency solution includes: for any hydraulic press, keeping the die pressing time and the maximum working time unchanged, dividing the difference between the maximum working time and the die pressing time into two parts, obtaining the optimal downstroke time and the optimal return time, then querying a test frequency-time graph to obtain the optimal downstroke frequency and the optimal return frequency corresponding to the optimal downstroke time and the optimal return time, and then combining the optimal downstroke frequency, the optimal return frequency and the die pressing frequency into the optimal frequency solution; The optimal downlink time and the optimal return time are respectively greater than the minimum downlink time and the minimum return time.

8. The method for optimizing frequency conversion and energy saving of a hydraulic press according to claim 7, characterized in that: The test frequency-time diagram includes a test frequency-downlink time diagram and a test frequency-return time diagram.

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