A control circuit of an injection molding device of a new energy vehicle and the injection molding device

Abstract

The application discloses a control circuit of an injection molding equipment applied to a new energy vehicle and the injection molding equipment. The control circuit comprises a capacitor adjusting module, a sensing module and a control module. The capacitor adjusting module is used for adjusting a capacitor capacity value. The sensing module is used for detecting the capacitor capacity value output by the capacitor adjusting module. The control module is used for setting and outputting a time interval between adjacent control periods of a switching device based on a time threshold sequence. The control circuit can be compatible with different application scenarios and stable injection molding effects can be obtained.

Description

Technical Field

[0001] This application relates to the field of new energy vehicles, and in particular to the control circuit and injection molding equipment for new energy vehicles. Background Technology

[0002] In the current new energy vehicle sector, the typical operating conditions of specialized injection molding equipment mainly include core processes such as injection, pressure holding, melt storage, cooling and shaping, and product ejection. The entire injection molding process generally relies on motors to drive the various mechanisms, and the motor's drive is typically controlled by the on / off switching of multiple switching devices. The control signals often employ drive signals with fixed carrier periods and fixed pulse widths.

[0003] This fixed-mode drive signal modulation method concentrates electromagnetic energy at certain frequencies, causing the overall machine's radiated and conducted noise to exceed standards. Industry practice typically involves adding filtering, magnetic rings, shielding, and other suppression measures to the motor's drive control circuit to improve the system's electromagnetic interference characteristics; however, this is a reactive solution.

[0004] In addition, in the injection molding scenario of new energy vehicle parts, there are many types of plastic parts with large differences in structural dimensions. Plastic parts of different sizes, wall thicknesses and materials have significant differences in injection pressure, injection speed, holding pressure parameters, back pressure and process flow. The corresponding motor speed, load torque and dynamic response requirements are also completely different.

[0005] Existing traditional injection molding motor control schemes mostly employ fixed pulse width modulation algorithms, which cannot match the differentiated driving requirements of sized plastic parts. They have weak adaptability to operating conditions and poor scenario compatibility, making it difficult to balance interference suppression, motor operation stability, and the molding quality of precision plastic parts for new energy vehicles. If the same control scheme is used for plastic parts of different specifications, it is difficult to guarantee anti-interference performance.

[0006] Therefore, there is an urgent need to design an adaptive motor drive control strategy for molding new energy plastic parts of different specifications, so as to be compatible with new energy plastic parts of different specifications. Summary of the Invention

[0007] The purpose of this invention is to provide a control circuit compatible with new energy plastic parts of different specifications.

[0008] The present invention provides a control circuit comprising: Capacitor adjustment module, used to adjust the capacitance value; The sensing module is electrically connected to the capacitor regulation module and is used to detect the capacitance value output by the capacitor regulation module. The judgment module is electrically connected to the sensing module and is used to determine the preset range to which the capacitance value detected by the sensing module belongs, and to determine a time threshold sequence based on the range to which the capacitance value belongs. The control module, electrically connected to the judgment module, is used to set and output the time interval between adjacent control cycles of the control switching device based on a time threshold sequence; wherein each value in the time threshold sequence corresponds to a time interval; the switching device is used to drive the motor of the injection molding equipment. In this application, multiple sets of switching devices are used to drive the motor to achieve injection molding.

[0009] In some implementations, the capacitor regulation module includes multiple branches connected in parallel, each branch including a base capacitor branch and multiple regulating capacitor branches; the base capacitor branch includes a base capacitor, and each regulating capacitor branch includes a capacitor connected in series and a switching component.

[0010] In some implementations, the on / off state of each switching component in multiple regulating capacitor branches is determined according to the specification grade of the part to be injection molded; the specification grade of the part to be injection molded is matched with the size and wall thickness of the part to be injection molded.

[0011] In some implementations, during the injection molding process of the injection molding equipment, the time threshold sequence changes periodically, and the change pattern corresponds one-to-one with the preset range of the capacitance value.

[0012] In some implementations, the specific values ​​of each time threshold in the time threshold sequence are obtained by periodically sampling the sine waveform of the sine signal, the sine waveform of the cosine signal, or the triangular wave signal.

[0013] In some implementations, the amplitude and period of the sine, cosine, and triangular wave signals are controlled within a preset range of the capacitor value.

[0014] In some implementations, the higher the specification level, the larger the amplitude of the sine, cosine, and triangular wave signals, and / or the smaller the period of the sine, cosine, and triangular wave signals, the more material is required for the injection molded part based on its size and wall thickness.

[0015] In some implementations, the control module includes a first timing module and a second timing module; Controlled by the first timing signal, the first timing module starts timing and controls the control signal used to control the switching device to a first level; when the first timing module times to a first threshold, it controls the control signal to a second level; when the first timing module times out, it outputs an enable signal. Controlled by the enable signal, the second timing module starts timing. When the second timing module reaches the second threshold, it outputs a reset signal, which serves as the first timing signal of the aforementioned first timing module.

[0016] Another aspect of this application provides an injection molding system, which includes an injection molding device and a control circuit as described in the first aspect above; the control circuit is electrically connected to the motor of the injection molding device and is used to control the operating state of the motor. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below.

[0018] Figure 1 A control circuit provided in an embodiment of the present invention; Figure 2 A capacitor adjustment module provided in an embodiment of the present invention; Figure 3 This invention provides a time threshold sequence value one. Figure 4 This invention provides a time threshold sequence value two. Figure 5 This invention provides a time threshold sequence value three; Figure 6 This is a schematic diagram of the control module provided in an embodiment of the present invention; Figure 7 The waveform diagram is shown in the embodiment of the present invention. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In the injection molding of new energy vehicle parts, there are many types of plastic parts with different structural dimensions. For plastic parts of different sizes, wall thicknesses and materials, there are significant differences in injection pressure, injection speed, holding pressure parameters, back pressure and process flow.

[0021] Currently, there is no control circuit that can be compatible with the molding of new energy plastic parts of different specifications. Different control circuits are usually required for different specifications of the parts to be injection molded. If the specifications of the plastic part change, using a fixed existing algorithm often fails to guarantee anti-interference performance and makes it difficult to achieve good injection molding results.

[0022] like Figure 1As shown, in order to address the above problems, the present invention proposes a control circuit that is compatible with new energy plastic parts of different specifications. The control circuit includes: a capacitor adjustment module 11, a sensing module 12, a judgment module 13, and a control module 14. The capacitor adjustment module 11 is used to adjust the capacitance value. Different capacitance values ​​can represent different specifications of the part to be injection molded, helping the system to determine which control algorithm to use. The specifications of the part to be injection molded represent information related to its size and wall thickness. After the operator determines the specifications of the part to be injection molded, they can set the corresponding capacitance value according to a pre-set specification information and capacitance value lookup table.

[0023] The sensing module 12 is electrically connected to the aforementioned capacitor adjustment module 11 and is used to detect the capacitance value output by the capacitor adjustment module 11. The capacitance value can be determined by charging or discharging the capacitor in the capacitor adjustment module 11 with a fixed current. Of course, other methods can also be used. Since the method of detecting capacitance is a relatively well-known technology, this application will not elaborate on it here.

[0024] The judgment module 13 is electrically connected to the sensing module 12 and is used to determine the preset range to which the capacitance value detected by the sensing module 12 belongs, and to determine a time threshold sequence based on the range to which the capacitance value belongs. A table corresponding to capacitance range and time threshold sequence can be pre-set. The judgment module 13 determines the corresponding time threshold sequence based on the capacitance range to which the capacitance value belongs.

[0025] The control module 14 is electrically connected to the judgment module 13 and is used to set and output the time interval between adjacent control cycles of the control switching device based on the aforementioned time threshold sequence; wherein each value in the aforementioned time threshold sequence corresponds to a time interval.

[0026] It should be noted that this application can drive the motor by controlling the on / off state of multiple switching devices (typically using PWM signals). For each switching device, its control cycle is T. Within one control cycle, the control signal that turns the switching device on is generated. Within one control cycle, the switching device can be turned on when the modulated pulse width modulation signal is high and turned off when the modulated signal is low. The interval time refers to the time between the previous control cycle and the next control cycle. For example, t1-t2 is T, which is the first control cycle, and t3-t4 is T, which is the second control cycle. The interval between t2-t3 is the time between the first and second control cycles, i.e., the blank time. During the blank time, no valid signal to turn the switching device on is generated. Each value in the above time threshold sequence corresponds to the duration of a blank time. For example, assuming the time threshold sequence is {1,2}, for three control cycles A, B, and C, the blank time between cycle A and cycle B is 1, and the blank time between cycle B and cycle C is 2. During idle time, the pulse width modulation signal clock remains at an invalid level, and the motor will not be driven.

[0027] In this application, a time threshold sequence is determined by adjusting the capacitance value, and then the blank time is determined by the corresponding value in the time threshold sequence. Adding blank time between adjacent control cycles ensures the anti-interference performance of the control system. The capacitance value can characterize different specifications of the injection molded parts; therefore, it can be applied to the processing of injection molded parts of different specifications, exhibiting high compatibility and stability of the control circuit.

[0028] like Figure 2 As shown, in some embodiments, the capacitor adjustment module 11 includes multiple branches arranged in parallel, the aforementioned multiple branches arranged in parallel include a basic capacitor branch and multiple adjustment capacitor branches; the basic capacitor branch includes a basic capacitor, and each of the adjustment capacitor branches includes a capacitor and a switching component connected in series.

[0029] In this embodiment, the number of conducting capacitor branches is determined by controlling the on / off state of the switching components of each branch, thereby determining the equivalent capacitance value. Operators can adjust the capacitance value based on their own estimates or the specifications of the injection-molded part, thus matching the most suitable control algorithm.

[0030] In some embodiments, the control circuit of this application determines the on / off state of each switching component in the plurality of regulating capacitor branches according to the specification level of the part to be injection molded; the specification level of the part to be injection molded is matched with the size and wall thickness of the part to be injection molded. For example, if the size of the part to be injection molded (e.g., length, width, etc.) is greater than a preset threshold and the wall thickness is greater than a preset threshold, then the specification level of the part to be injection molded is determined to be high, and the capacitance value corresponding to the high specification level is determined. Conversely, if the size of the part to be injection molded is less than a preset value and the wall thickness is less than a preset value, then the specification level is determined to be low, and the capacitance value corresponding to the low specification level is determined.

[0031] In some implementations, during the injection molding process of the injection molding equipment, the time thresholds in the time threshold sequence change periodically, and the change pattern of each time threshold corresponds one-to-one with the preset range of the capacitance value. For example, the time threshold sequence changes periodically according to the pattern 1, 2, 3, 2, 1, 1, 2, 3, 2, 1… Then the blank time between adjacent control cycles is 1, 2, 3, 2, 1, 1, 2, 3, 2, 1…

[0032] In some implementations, the specific values ​​of each time threshold in the time threshold sequence are obtained by periodically sampling the absolute value of the sine signal, the absolute value of the cosine signal, or the triangular wave signal. Figures 3-5 Taking a sine wave as an example, say sinX; first, take the absolute value of sinX to obtain |sinX|. If the sampling period is r, then |sinX| is sampled once every r time intervals. The sequence obtained by sampling is the aforementioned time threshold sequence, such as... Figure 3 As shown.

[0033] In some implementations, the amplitude and period of the sine wave, cosine wave, and triangular wave signals are all controlled within a preset range of capacitor values, and correspond one-to-one with that preset range. Taking a sine wave as an example, if the capacitor value is 10, a sine wave amplitude of 5 can be selected; when the capacitor value is 20, it indicates a higher specification level, and in this case, a sine wave amplitude of 10 can be selected.

[0034] In this application, the capacitance value is determined according to the specification level of the part to be injection molded, and then the amplitude and period of the sine wave signal, cosine wave signal and triangular wave signal are determined according to the capacitance value, so as to obtain control parameters that are suitable for the specification level of the part to be injection molded.

[0035] In some implementations, when the specification grade is determined based on the size and wall thickness of the part to be injection molded, the higher the grade, the larger the amplitude of the sine signal, cosine signal, and triangular wave signal, and / or the smaller the period of the sine signal, cosine signal, and triangular wave signal.

[0036] Preferably, if the specification level is determined to be high based on the size and wall thickness, such as for a large-sized, thick-walled injection molded part, then it is necessary to appropriately increase the amplitude of each signal and decrease the period value of each signal.

[0037] like Figure 6 As shown, in some embodiments, the control module 14 further includes a first timing module 141 and a second timing module 142; Controlled by the first timing signal, the first timing module 141 starts timing and controls the control signal used to control the switching device to the first level; when the first timing module 141 times to the first threshold, it controls the control signal to the second level; when the first timing module 141 times out, it outputs an enable signal EN. Controlled by the enable signal EN, the second timing module 142 starts timing. When the second timing module 142 times to the second threshold, it outputs a reset signal RE, which serves as the first timing signal of the first timing module 141.

[0038] like Figure 7 As shown, at time t1, the first timing module 141 receives the first timing signal RE and starts timing. Simultaneously, controlled by the first timing signal RE, the control signal PWM flips to a first level at t1, for example, flipping high. When the first timing module 141 times out to a first threshold (i.e., at time t2), the control signal PWM flips to a second level at t2, for example, flipping from high to low. The time the PWM is high indicates that the control signal is valid, and the corresponding switching device is turned on. When the first timing module 141 has completed its timing (i.e., at time t3), the first timing module 141 outputs an enable signal EN at t3. In other words, the first timing module 141 has two timing thresholds. When the first threshold is reached, the control PWM flips low. When the first timing module 141 times out to the second threshold, it indicates that the timing cycle of the timing module has ended, the timing module stops timing, and the first timing module 141 is reset, waiting for the next first timing signal to arrive before starting a new timing cycle (i.e., a control cycle).

[0039] At time t3, when the second timing module 142 receives the enable signal EN output by the first timing module 141, the second timing module 142 starts timing. When the second timing module 142 times to the second threshold (i.e., time t4), it outputs a reset signal RE. The reset signal RE serves as the first timing signal of the first timing module 141 to trigger the first timing module 141 to start a new cycle of timing.

[0040] Optionally, the enable signal EN and the reset signal RE can be selected as pulse signals.

[0041] It should be noted that the timing period of the first timing module 141 actually corresponds to the aforementioned control cycle T. Afterwards, the second timing module 142 receives the aforementioned enable signal EN and begins timing. When the timing reaches the second threshold, it outputs a reset signal RE as the first timing signal to trigger the first timing module 141 to start timing in the next control cycle. It can be seen that the magnitude of the second threshold corresponds to the magnitude of the blank time between two control cycles. Therefore, the second threshold actually corresponds to the value in the time threshold sequence. As time changes, the second threshold sequentially takes on each threshold in the time threshold sequence. For example, according to... Figure 7 The blank time between the first control period (t1-t3) and the second control period (t4-t6) is called Delay1, and the blank time between the second control period (t4-t6) and the third control period is called Delay2. Delay1 and Delay2 are the two thresholds in the time threshold sequence.

[0042] This application also provides an injection molding system, which includes an injection molding machine and a control circuit as described in the first aspect above; the control circuit is electrically connected to the motor of the injection molding machine and is used to control the operating state of the motor to adapt to the operating requirements of the injection molding machine under various working conditions.

Claims

1. A control circuit for injection molding equipment used in new energy vehicles, characterized in that, include: Capacitor adjustment module, used to adjust the capacitance value; A sensing module, electrically connected to the capacitor adjustment module, is used to detect the capacitance value output by the capacitor adjustment module. The judgment module is electrically connected to the sensing module and is used to determine the preset range to which the capacitance value detected by the sensing module belongs, and to determine a time threshold sequence based on the range to which the capacitance value belongs. The control module, electrically connected to the judgment module, is used to set and output the time interval between adjacent control cycles of the control switching device based on the time threshold sequence; wherein each value in the time threshold sequence corresponds to a time interval; the switching device is used to drive the motor of the injection molding equipment.

2. The control circuit according to claim 1, characterized in that, The capacitor regulation module includes multiple branches connected in parallel, each branch including a base capacitor branch and multiple regulating capacitor branches; the base capacitor branch includes a base capacitor, and each regulating capacitor branch includes a capacitor connected in series and a switching component.

3. The control circuit according to claim 2, characterized in that, The on / off state of each switch component in the plurality of regulating capacitor branches is determined according to the specification grade of the part to be injection molded; the specification grade of the part to be injection molded is matched with the size and wall thickness of the part to be injection molded.

4. The control circuit according to claim 3, characterized in that, During the injection molding process of the injection molding equipment, the time threshold sequence changes periodically, and the change pattern corresponds one-to-one with the preset range of the capacitance value.

5. The control circuit according to claim 4, characterized in that, The specific values ​​of each time threshold in the time threshold sequence are obtained by periodically sampling the absolute value of the sine signal, the absolute value of the cosine signal, or the triangular wave signal.

6. The control circuit according to claim 5, characterized in that, The amplitude and period of the sine, cosine, and triangular wave signals are controlled within a preset range of the capacitance value.

7. The control circuit according to claim 6, characterized in that, The higher the specification level determined based on the size and wall thickness of the part to be injection molded, the greater the amplitude of the sine signal, cosine signal, and triangular wave signal and / or the smaller the period of the sine signal, cosine signal, and triangular wave signal.

8. The control circuit according to any one of claims 1-7, characterized in that, The control module includes a first timing module and a second timing module; Controlled by the first timing signal, the first timing module starts timing and controls the control signal used to control the switching device to a first level; when the first timing module times to a first threshold, it controls the control signal to a second level; when the first timing module times out, it outputs an enable signal. Controlled by the enable signal, the second timing module starts timing. When the second timing module reaches the second threshold, it outputs a reset signal, which serves as the first timing signal of the first timing module.

9. An injection molding system, characterized in that, It includes an injection molding machine and a control circuit as described in any one of claims 1 to 8; the control circuit is electrically connected to the motor of the injection molding machine and is used to control the operating state of the motor.

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