Resonant transformation circuit control method, laser therapy apparatus and storage medium
By switching the segmental operating mode of the resonant converter circuit at different operating stages of the laser device and flexibly controlling the duty cycle and frequency of the upper and lower switching devices, the problem of the traditional resonant converter circuit being unable to maintain stable power supply voltage is solved, and voltage stability during the laser device's light output process is achieved.
Patent Information
- Application Number
- CN202511422004.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-30
- Publication Date
- 2026-02-06
AI Technical Summary
Traditional resonant converter circuits cannot effectively maintain the stability of the power supply voltage in the pulsed light output mode of laser equipment, resulting in unstable light output and affecting the effectiveness and safety of medical surgery.
By controlling the resonant converter circuit to enter different operating modes, the duty cycle and operating frequency of the upper and lower switching devices can be flexibly adjusted to achieve stable control of the power supply voltage.
By switching between different operating modes and adjusting the duty cycle of independent control devices at different stages of laser equipment operation, the stability of the power supply voltage is improved, ensuring the voltage stability of the laser equipment throughout the entire light output process.
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Figure CN121485484A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of medical laser technology, and in particular to a resonant converter circuit control method, a laser therapy machine, and a storage medium. Background Technology
[0002] In the field of medical laser technology, if the power supply voltage for exciting the laser cannot be kept stable, it will affect the light output stability of the medical laser equipment, thereby affecting the effectiveness and safety of the surgery.
[0003] In traditional technology, resonant converter circuits are typically used to adjust the supply voltage. When a laser device operates in pulsed emission mode, during the emission phase, the laser device is emitting light, and the resonant converter circuit outputs a preset load power to meet the power requirements of the laser device during emission. During the emission-off phase, the laser device stops emitting light, and the resonant converter circuit has no rated power output, operating under light load or no load. Normally, if the load becomes lighter, the operating frequency of the resonant converter circuit needs to be increased to move away from the resonant frequency, thereby reducing the output voltage of the resonant converter circuit to maintain the stability of the laser supply voltage. However, the adjustment capability of the resonant converter circuit is limited and cannot meet the requirement of maintaining a stable supply voltage throughout the entire pulsed emission mode of the laser device. Summary of the Invention
[0004] Based on this, it is necessary to provide a resonant converter circuit control method, a laser therapy machine, and a storage medium that can improve the stability of the power supply voltage of a laser device in pulsed light output mode, in order to address the above-mentioned technical problems.
[0005] Firstly, a resonant converter circuit control method is provided, applied to laser devices, the method comprising:
[0006] In response to the startup of the laser device, the control resonant converter circuit enters the first section working mode; wherein, in the first section working mode, the working frequency of the resonant converter circuit remains fixed, the upper switching device in each bridge arm of the resonant converter circuit operates in the duty cycle adjustable mode, and the lower switching device in each bridge arm of the resonant converter circuit operates in the preset fixed duty cycle mode.
[0007] In response to the duty cycle of the upper switching device being adjusted to a preset value, the resonant converter circuit is controlled to enter the second-segment operating mode; and
[0008] In response to the laser device stopping light emission, the control resonant converter circuit switches from the second-segment operating mode to the first-segment operating mode.
[0009] In some embodiments, the method further includes:
[0010] In response to the normal light output of the laser device, the control resonant converter circuit is kept in the second section working mode.
[0011] In some embodiments, before controlling the resonant converter circuit to enter the first segment operating mode, the method further includes:
[0012] The upper switching device is controlled to remain in the off state for a preset number of switching cycles, while the lower switching device is controlled to be turned on intermittently with a preset fixed duty cycle.
[0013] In some embodiments, before the duty cycle of the upper switching device is adjusted to a preset value, the method further includes:
[0014] Obtain the calculated voltage loop and current loop values for the resonant converter circuit;
[0015] Calculate the current duty cycle based on the voltage loop calculation value and the current loop calculation value;
[0016] Adjust the duty cycle of the upper switching device according to the current duty cycle.
[0017] In some embodiments, after controlling the resonant converter circuit to enter the second segment operating mode, the method further includes:
[0018] In the second-section operating mode, the duty cycle of the upper and lower switching devices is kept constant, and the operating frequency of the resonant converter circuit is adjusted.
[0019] In some embodiments, adjusting the operating frequency of the resonant converter circuit includes:
[0020] Obtain the calculated voltage loop and current loop values for the resonant converter circuit;
[0021] Calculate the current operating frequency based on the voltage loop calculation value and the current loop calculation value;
[0022] Adjust the operating frequency of the resonant converter circuit according to the current operating frequency.
[0023] In some embodiments, before the control resonant converter circuit switches from the second segment operating mode to the first segment operating mode, the method further includes:
[0024] In response to the operating frequency of the resonant converter circuit being adjusted to the highest operating frequency, the current output voltage of the resonant converter circuit is obtained, and it is determined whether the current output voltage is greater than the rated voltage.
[0025] In response to the current output voltage being greater than the rated voltage, the control resonant converter circuit switches from the second-segment operating mode to the first-segment operating mode.
[0026] In some embodiments, the upper switching device includes a first switching device and a third switching device, and the lower switching device includes a second switching device and a fourth switching device; wherein...
[0027] The upper switching devices in each arm of the resonant converter circuit operate in an adjustable duty cycle mode, and the lower switching devices in each arm of the resonant converter circuit operate in a preset fixed duty cycle mode, including:
[0028] The first trigger pulse and the second trigger pulse are controlled by the independent first and second comparison registers, respectively.
[0029] The pulse controls the first switching device to operate in an adjustable duty cycle mode by a first trigger pulse, and controls the second switching device to operate in a preset fixed duty cycle mode by a second trigger pulse.
[0030] In some embodiments, the method further includes:
[0031] The third and fourth trigger pulses are controlled by independent third and fourth comparison registers, respectively; wherein the third trigger pulse is out of phase with the first trigger pulse, and the fourth trigger pulse is out of phase with the second trigger pulse.
[0032] The third trigger pulse controls the third switching device to operate in an adjustable duty cycle mode, and the fourth trigger pulse controls the fourth switching device to operate in a preset fixed duty cycle mode.
[0033] In some embodiments, the method further includes:
[0034] The rising edge dead time is set independently in the first trigger pulse;
[0035] The falling edge dead zone is set independently in the second trigger pulse.
[0036] Secondly, a laser therapy machine is also provided, comprising at least a controller and a resonant conversion circuit, wherein...
[0037] The controller is configured to perform the steps of any of the methods described in the first aspect above.
[0038] Thirdly, a computer-readable storage medium is provided having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of any one of the methods of the first aspect described above.
[0039] The aforementioned resonant converter circuit control method, laser therapy machine, and storage medium control the resonant converter circuit to enter different operating modes depending on the different stages of laser device operation. When the laser device starts up, the resonant converter circuit is controlled to enter the first operating mode. After the laser device is in a relatively stable state, it enters the second operating mode, at which time the laser device can emit light normally. When the light emission state of the laser device changes, that is, when light emission stops, the resonant converter circuit is controlled to switch from the second operating mode back to the first operating mode. This solution allows for targeted control of the resonant converter circuit to enter either the first or second operating mode, based on the various stages of laser equipment operation, including startup, normal light output, and shutdown. Furthermore, in the first operating mode, the upper and lower switching devices in each arm of the resonant converter circuit are flexibly and independently controlled to operate in different duty cycle modes (adjustable duty cycle mode and preset fixed duty cycle mode). Therefore, the gain of the resonant converter circuit can be flexibly, smoothly, and over a wider range of applications throughout the laser equipment's startup, normal light output, and shutdown stages, thereby improving the stability of the power supply voltage throughout the entire light output process. Attached Figure Description
[0040] Figure 1 These are schematic diagrams of the laser device in some embodiments;
[0041] Figure 2 This is a flowchart illustrating the control method of the resonant converter circuit in some embodiments;
[0042] Figure 3 This is a schematic diagram of the resonant converter circuit in some embodiments;
[0043] Figure 4 This is a schematic diagram of the pulse waveforms of the first trigger pulse and the second trigger pulse, which are generated independently by the first comparison register and the second comparison register, respectively, in some embodiments.
[0044] Figure 5 The above are waveform diagrams illustrating how, in some embodiments, the first and second switching devices are controlled to operate in different modes by means of a first trigger pulse and a second trigger pulse, respectively, and how the third and fourth switching devices are controlled to operate in different modes by means of a third trigger pulse and a fourth trigger pulse, respectively.
[0045] Figure 6 Here are gain curves for conventional resonant converter circuits in some embodiments;
[0046] Figure 7This is a schematic diagram comparing the supply voltage of a laser device using the resonant converter circuit control method of this application with the supply voltage of a laser device using the surge mode resonant converter circuit control method in some embodiments. Detailed Implementation
[0047] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0048] The resonant converter circuit control method provided in this application can be applied to, for example... Figure 1 The application environment shown. Among them, Figure 1 Schematic diagrams of laser devices in some embodiments are shown. Specifically, laser device 100 may include at least a controller 110 and a resonant converter circuit 120, the controller 110 being configured to perform the steps of the resonant converter circuit control method according to embodiments of this application.
[0049] Those skilled in the art will understand that Figure 1 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the laser device to which the present application is applied. Specific laser devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.
[0050] For example, the laser device 100 can be used in medical laser devices, such as laser therapy machines. For example, it can be used in holmium laser therapy machines and thulium laser therapy machines for urological lithotripsy and soft tissue cutting, carbon dioxide laser therapy machines for precise vaporization and excision in dermatology, excimer laser therapy machines for myopia correction in ophthalmology, and erbium laser therapy machines for teeth whitening and hard tissue treatment in dentistry.
[0051] For example, the resonant converter circuit 120 can be a bridge resonant converter circuit, which may include, but is not limited to, LLC (Inductor-Inductor-Capacitor) resonant converter circuit and CLLC (Capacitor-Inductor-Inductor-Capacitor) resonant converter circuit.
[0052] In some embodiments, such as Figure 2 As shown, a resonant converter circuit control method is provided, which is applied to... Figure 1 Taking a laser device as an example, the following steps may be included:
[0053] In step S202, in response to the laser device entering the initial startup phase, the control resonant conversion circuit enters the first segment working mode.
[0054] In this context, the upper switching device refers to the one of the two series-connected switching devices constituting the bridge arm, located closer to the high-voltage end of the DC bus (or the positive input side of the bridge arm). The lower switching device refers to the one of the two series-connected switching devices constituting the bridge arm, located closer to the low-voltage end of the DC bus (or the negative input / ground side of the bridge arm). The upper and lower switching devices work together, receiving different pulse control signals, such as PWM (Pulse Width Modulation) signals, to switch between on and off states, thereby regulating the voltage, current, or power output of the bridge arm.
[0055] In this embodiment, in the first segment working mode, the operating frequency of the resonant converter circuit can be controlled to remain constant, and the upper switching devices in each bridge arm of the resonant converter circuit can be controlled to operate in the duty cycle adjustable mode, while the lower switching devices in each bridge arm of the resonant converter circuit operate in the preset fixed duty cycle mode.
[0056] The duty cycle adjustable mode refers to the operation of the upper switching device in each bridge arm under an adjustable duty cycle. That is, the duty cycle of the corresponding trigger pulse can be dynamically adjusted according to the actual output voltage and / or output current of the resonant converter circuit. Preferably, in the duty cycle adjustable mode, the duty cycle (ratio_up) of the trigger pulse corresponding to the upper switching device can be adjusted within the range of 10% to 50%.
[0057] The preset fixed duty cycle mode means that the lower switching device in each bridge arm always operates with a preset and constant duty cycle. That is, the duty cycle of its corresponding trigger pulse does not change with the output voltage or output current of the resonant converter circuit. Preferably, the duty cycle (ratio_down) of the trigger pulse corresponding to the lower switching device can be set to 50%. Of course, it can also be set to a fixed custom optimal value.
[0058] In step S204, in response to the duty cycle of the upper switching device being adjusted to a preset value, the resonant converter circuit is controlled to enter the second segment working mode.
[0059] In the second-section operating mode, the duty cycle of the upper switching device and the duty cycle of the lower switching device can be kept constant, thereby adjusting the operating frequency of the resonant converter circuit.
[0060] Specifically, in the first segment working mode, the duty cycle of the upper switching device gradually widens within a preset adjustable range. For example, the duty cycle of the upper switching device can gradually widen from 10% to 50% and then reach the highest threshold of the adjustable range. Then, the highest threshold of the adjustable range can be used as the preset value. At this time, an identification flag can be set at the duty cycle of 50%. When the program runs to the point where the duty cycle is adjusted to 50% (preset value), it enters the second segment working mode.
[0061] For example, in the second-section operating mode, the duty cycles of the upper and lower switching devices can be kept constant while adjusting the operating frequency of the resonant converter circuit. For instance, the duty cycles of all switching devices (typically, both the upper and lower switching devices are fixed at 50%) are kept constant, and the gain is changed by adjusting the operating frequency of the resonant converter circuit, thereby controlling the output voltage and output power, etc. The second-section operating mode can employ the classic frequency adjustment mode of resonant converter circuits such as LLC or CLLC.
[0062] In step S206, in response to the decrease in the power required by the load of the resonant converter circuit, the resonant converter circuit is controlled to switch from the second segment operating mode to the first segment operating mode.
[0063] In this step, when the laser device stops emitting light, the load on the resonant converter circuit becomes lighter or even close to zero. The output power required by the load on the resonant converter circuit decreases accordingly. At this time, the operating mode can be switched from the second-segment operating mode to the first-segment operating mode. In the first-segment operating mode, by putting the upper switching device in the duty cycle adjustable mode, the output power can be reduced to a greater extent, and the power of the resonant converter circuit can be reduced more effectively, thereby maintaining the stability of the output power of the laser device.
[0064] The aforementioned resonant converter circuit control method controls the resonant converter circuit to enter different operating modes depending on the different operating stages of the laser device. When the laser device starts up, the resonant converter circuit is controlled to enter the first operating mode (laser startup). After the laser device is in a relatively stable state, it enters the second operating mode (laser emission). At this time, the laser device can emit light normally. When the emission state of the laser device changes, that is, when the emission stops, the resonant converter circuit is controlled to switch from the second operating mode back to the first operating mode. This solution allows for targeted control of the resonant converter circuit to enter either the first or second operating mode, based on the various stages of laser equipment operation, including startup, normal light output, and shutdown. Furthermore, in the first operating mode, the upper and lower switching devices in each arm of the resonant converter circuit are flexibly and independently controlled to operate in different duty cycle modes (adjustable duty cycle mode and preset fixed duty cycle mode). Therefore, the gain of the resonant converter circuit can be flexibly, smoothly, and over a wider range of applications throughout the laser equipment's operation, from startup and normal light output to shutdown, thereby improving the stability of the power supply voltage throughout the entire light output process.
[0065] In some embodiments, the method further includes: controlling the resonant converter circuit to maintain the second segment operating mode in response to normal light output from the laser device.
[0066] In this embodiment, when the laser device is started and in normal light output mode, the load of the resonant conversion circuit is a conventional load. The power required by the load of the resonant conversion circuit is within a preset range. That is, when the resonant conversion circuit reaches the preset rated output voltage or rated output current, the resonant conversion circuit can be maintained in the second section working mode, thereby maintaining the light output stability of the laser device.
[0067] In some embodiments, before the resonant converter circuit enters the first segment operating mode, the method further includes: controlling the upper switching device to remain in the off state for a preset number of switching cycles, and controlling the lower switching device to be turned on intermittently with a preset fixed duty cycle.
[0068] In this embodiment, before entering the first segment working mode, the upper switching device can remain in the off state for a preset number of first few cycles, while the lower switching device is turned on and off alternately with a preset fixed duty cycle (e.g., 50%). This releases the charge stored on the parasitic capacitance (COSS) of the lower switching device, which helps to reduce the amplitude of the first pulse current of the primary current of the transformer in the resonant converter circuit when the laser device is first turned on, thereby avoiding current spikes impacting the laser and shortening its lifespan.
[0069] In some embodiments, before the duty cycle of the upper switching device is adjusted to a preset value, the method further includes: obtaining the voltage loop calculation value and the current loop calculation value of the resonant converter circuit; calculating the current duty cycle based on the voltage loop calculation value and the current loop calculation value; and adjusting the duty cycle of the upper switching device based on the current duty cycle.
[0070] In this embodiment, before adjusting the duty cycle of the upper switching device to a preset value, the voltage loop calculation value (e.g., represented by GV_OUT) and current loop calculation value (e.g., represented by GI_OUT) of the resonant converter circuit can be obtained in real time. Based on these two parameters, the optimal current duty cycle is calculated. For example, the two can be compared and the smaller value can be selected to determine the current duty cycle. The determined current duty cycle value (duty value) is then transmitted to the parameter ratio_up to control the duty cycle of the upper switching device.
[0071] For example, the specific calculation method for the optimal current duty cycle can be referred to as follows:
[0072] The current loop calculation value can be obtained as follows: by reading the current reference value and the actual current sample value, the difference between the two is taken as the error value of the current loop; the error value of the current loop is input to the PID (Proportional-Integral-Derivative) controller of the current loop to obtain the control value output by the PID controller of the current loop, and this control value is taken as the current loop calculation value.
[0073] Furthermore, a pre-calculation function can be called to update the internal state variables of the PID controller for the current loop in advance based on the error value and the calculated value of the current loop, thereby preparing for the calculation of the next sampling cycle.
[0074] The voltage loop calculation value can be obtained as follows: by reading the voltage reference value and the actual voltage sample value, the difference between the two is taken as the voltage loop error value; the voltage loop error value is input to the voltage loop PID controller to obtain the control value output by the voltage loop PID controller, and this control value is taken as the voltage loop calculation value.
[0075] Furthermore, a pre-calculation function can be invoked to update the internal state variables of the PID controller of the voltage loop in advance based on the current voltage loop error value and the calculated voltage loop value, thereby preparing for the calculation of the next sampling cycle.
[0076] After obtaining the calculated values of the current loop and voltage loop, the two values are compared. If the calculated value of the current loop is greater than the calculated value of the voltage loop, the calculated value of the voltage loop is selected as the final control value; if the calculated value of the current loop is less than the calculated value of the voltage loop, the calculated value of the current loop is selected as the final control value. The final control value is assigned to the comparison register of the PWM module for adjusting the duty cycle of the upper switching device, thereby determining the optimal current duty cycle.
[0077] In this embodiment, in the first-segment operating mode, the duty cycle of the upper switching device is calculated by taking into account both the voltage loop and the current loop, and selecting the smaller value between the two. The reason for selecting the smaller value is based on the safety strategy of dual protection. If the larger error is prioritized, it may cause the loop with the smaller error to overload. Therefore, this embodiment can effectively prevent the overload of the other loop caused by the excessive calculation value of a single loop during dynamic startup, thereby achieving dual protection against overvoltage and overcurrent. In addition, it can allow the circuit system to seamlessly switch between constant voltage (CV) and constant current (CC) modes.
[0078] In some embodiments, adjusting the operating frequency of the resonant converter circuit includes: obtaining the voltage loop calculated value and the current loop calculated value of the resonant converter circuit; calculating the current operating frequency based on the voltage loop calculated value and the current loop calculated value; and adjusting the operating frequency of the resonant converter circuit based on the current operating frequency.
[0079] In this embodiment, in the second segment operating mode, the voltage loop calculation value and current loop calculation value of the resonant converter circuit can be obtained in real time. Based on these two parameters, the optimal current operating frequency can be calculated. For example, the current operating frequency can be determined by comparing the two and selecting the smaller value. The determined value is then transmitted to PWM_PERIOD (half a cycle of the timer in the PWM module) to adjust the operating frequency of the resonant converter circuit.
[0080] In this embodiment, in the second-segment operating mode, the calculation of the operating frequency of the resonant converter circuit takes into account both the voltage loop and the current loop, and selects the smaller value between the two. This can effectively prevent the overload of the other loop due to the excessive calculation value of a single loop during dynamic startup, thereby achieving dual protection against overvoltage and overcurrent. In addition, it can allow the circuit system to seamlessly switch between constant voltage (CV) and constant current (CC) modes.
[0081] In some embodiments, before controlling the resonant converter circuit to switch from the second segment operating mode to the first segment operating mode, the method further includes: in response to the operating frequency of the resonant converter circuit being adjusted to the highest operating frequency, obtaining the current output voltage of the resonant converter circuit and determining whether the current output voltage is greater than the rated voltage; in response to the current output voltage being greater than the rated voltage, controlling the resonant converter circuit to switch from the second segment operating mode to the first segment operating mode.
[0082] In this embodiment, before switching from the second-segment operating mode to the first-segment operating mode, a step of comparing the current output voltage of the resonant converter circuit with its rated voltage can be added. If it is determined that the current output voltage of the resonant converter circuit is greater than its rated voltage, it means that in the second-segment operating mode, it is no longer possible to compensate for the voltage drop / fluctuation caused by load changes. Therefore, it is necessary to switch to the first-segment operating mode in a timely manner. However, if it is determined that the current output voltage of the resonant converter circuit is less than or equal to its rated voltage, it means that in the second-segment operating mode, the laser device can be kept stable in the light-emitting mode by adjusting the operating frequency. Therefore, it is not necessary to switch to the first-segment operating mode.
[0083] In some embodiments, to more clearly illustrate the resonant converter circuit control method involved in the embodiments of this application, reference can be made to... Figure 3 As shown, Figure 3 The diagrams shown here are schematic representations of the resonant converter circuits in some embodiments. It is worth noting that those skilled in the art will understand that... Figure 3 The circuit structure shown is merely a schematic diagram of a portion of the structure related to the solution of this application, and does not constitute a limitation on the resonant converter circuit applied thereto. The specific resonant converter circuit may include more or fewer components than those shown in the figure, or may have different component arrangements.
[0084] In some embodiments, reference Figure 3 The upper switching device includes a first switching device of the first bridge arm and a third switching device of the second bridge arm; the lower switching device includes a second switching device of the first bridge arm and a fourth switching device of the second bridge arm; wherein,
[0085] The upper switching devices in each arm of the resonant converter circuit operate in an adjustable duty cycle mode, and the lower switching devices in each arm of the resonant converter circuit operate in a preset fixed duty cycle mode. This includes: controlling the first trigger pulse EPWM1A and the second trigger pulse EPWM1B respectively through independent first and second comparison registers; controlling the first switching device to operate in an adjustable duty cycle mode through the first trigger pulse EPWM1A, and controlling the second switching device to operate in a preset fixed duty cycle mode through the second trigger pulse EPWM1B.
[0086] More specifically, in the traditional method, a single pulse source is used to generate a trigger pulse to control the resonant converter circuit. In this embodiment, two separate pulse sources are used, namely the first comparator register and the second comparator register, which generate the first trigger pulse EPWM1A and the second trigger pulse EPWM1B respectively. These pulses are used to independently control the upper and lower switching devices, thereby achieving independent control of the upper and lower switching devices in different modes. This improves the flexibility and accuracy of control, and thus improves the output stability of the laser device.
[0087] Specifically, the method for generating independent trigger pulses through the first comparison register and the second comparison register can be referred to as follows.
[0088] In the PWM (Pulse Width Modulation) module, set the counter to operate in UP-DOWN mode;
[0089] When the output channel A of the PWM module is configured to count up (UP) and the value of the counter matches the value of the first comparison register CMPA, the output is set to a high level (1); when a match occurs during the count down (DOWN) process, the output is set to a low level (0), thereby obtaining the first trigger pulse EPWM1A. The value of the first comparison register CMPA can be determined according to the calculated duty cycle ratio_up of the upper switching device. That is, the value of the first comparison register CMPA is set to make the duty cycle of the first trigger pulse EPWM1A output by it equal to the ratio indicated by the duty cycle ratio_up of the upper switching device.
[0090] During the up-counting (UP) process of the PWM module's output channel B, when the count value matches the value of the second comparison register CMPB, the output is set to a high level (1); during the down-counting (DOWN) process, when a match occurs, the output is set to a low level (0). Then, the waveform is reversed in polarity to obtain the second trigger pulse EPWM1B. The value of CMPB can be preset, for example, set to the value corresponding to a 50% duty cycle.
[0091] The above can be used as a reference. Figure 4 As shown in the understanding, Figure 4 The diagram shows the pulse waveforms of the first trigger pulse EPWM1A and the second trigger pulse EPWM1B, which are generated independently by the first comparator register CMPA and the second comparator register CMPB, respectively, in some embodiments.
[0092] For example, the following calculation formula can be used as a reference:
[0093] Leg1_pwmDutyAPrim_ticks=period*(1-ratio_up);
[0094] Leg1_pwmDutyBPrim_ticks=period*50%;
[0095] Where Leg1_pwmDutyAPrim_ticks represents the pulse width of the first trigger pulse EPWM1A, Leg1_pwmDutyBPrim_ticks represents the pulse width of the second trigger pulse EPWM1B, ratio_up represents the duty cycle of the upper switching device, and period represents the half-cycle of the timer of the PWM module.
[0096] According to the above formula, when the value of ratio_up is small, the value of period*(1-ratio_up) is large, and the pulse width of the first trigger pulse EPWM1A is narrow; when the value of ratio_up is large, the value of period*(1-ratio_up) is small, and the pulse width of the first trigger pulse EPWM1A is wide. For example, you can refer to... Figure 5 As shown, Figure 5 The diagram shows waveforms in some embodiments where a first trigger pulse and a second trigger pulse control a first switching device and a second switching device to operate in different modes, and a third trigger pulse and a fourth trigger pulse control a third switching device and a fourth switching device to operate in different modes, respectively.
[0097] In some embodiments, in order to satisfy the adaptation relationship of the circuit topology between the first bridge arm and the second bridge arm in the resonant converter circuit, the method may further include: controlling the third trigger pulse and the fourth trigger pulse respectively through the independent third comparison register and the fourth comparison register; wherein the third trigger pulse is opposite to the first trigger pulse, and the fourth trigger pulse is opposite to the second trigger pulse; controlling the third switching device to operate in the duty cycle adjustable mode through the third trigger pulse, and controlling the fourth switching device to operate in the preset fixed duty cycle mode through the fourth trigger pulse.
[0098] More specifically, the specific method for generating independent trigger pulses through the third comparator register CMPC and the fourth comparator register CMPD can refer to the specific method for generating independent trigger pulses through the first comparator register CMPA and the second comparator register CMPB as described above. It is worth noting that, in order to satisfy the adaptation relationship of the component topologies in each arm of the resonant converter circuit, the third trigger pulse generated through the third comparator register CMPC needs to be out of phase with the first trigger pulse generated through the first comparator register CMPA, i.e., out of phase by 180 degrees, and the fourth trigger pulse generated through the fourth comparator register CMPD needs to be out of phase with the second trigger pulse generated through the second comparator register CMPB, i.e., out of phase by 180 degrees. For example, the following calculation formula can be used as a reference:
[0099] Leg2_pwmDutyCPrim_ticks=period*ratio_up;
[0100] Leg2_pwmDutyDPrim_ticks=period*50%;
[0101] Where Leg2_pwmDutyCPrim_ticks represents the pulse width of the third trigger pulse EPWM2A, Leg2_pwmDutyDPrim_ticks represents the pulse width of the fourth trigger pulse EPWM2B, ratio_up represents the duty cycle of the upper switching device, and period represents the half-cycle of the PWM module's timer.
[0102] Through the above embodiments, it is possible to control the two sets of trigger pulses, EPWM1A / 1B and EMPW2A / 2B, respectively by using a single variable, namely the duty cycle ratio_up of the upper switching device, thereby reducing the complexity of circuit design.
[0103] In some embodiments, reference Figure 4 As shown, the method further includes: independently setting a rising edge dead time in the first trigger pulse; and independently setting a falling edge dead time in the second trigger pulse.
[0104] In this embodiment, based on the independent control of the first trigger pulse EPWM1A and the second trigger pulse EPWM1B, dead times are further set independently for each of them. That is, RED (Rising Edge Dead Time) is only effective for EPWM1A, and FED (Falling Edge Dead Time) is only effective for EPWM1B.
[0105] In this embodiment, by applying the rising edge dead time (RED) only to EPWM1A and the falling edge dead time (FED) only to EPWM1B, asymmetrical and refined control of the turn-off and turn-on processes of the upper and lower switching devices of the bridge circuit is achieved. This independent configuration strategy can more flexibly optimize switching losses and waveform quality while ensuring safety and preventing shoot-through.
[0106] The following is a detailed explanation of the beneficial effects that the resonant converter circuit control method involved in this application can achieve in medical devices such as laser equipment.
[0107] refer to Figure 6 As shown, Figure 6 Gain curves for conventional resonant converter circuits in some embodiments are shown. From Figure 6 As can be seen from this, for conventional resonant converter circuits, in practical applications, to ensure the performance of the resonant converter circuit, it is generally recommended to use, for example... Figure 6 The recommended operating frequency is adjusted within the area shown; however, from... Figure 6 As can be seen from the data, within this recommended range, the adjustment of the operating frequency fn of the resonant converter circuit has a relatively mild effect on the gain. Even when the operating frequency fn reaches the maximum operating frequency fmax, the gain remains high. Therefore, the gain adjustment capability of the resonant converter circuit itself is limited. If it is directly applied to laser devices, the supply voltage will still be higher than the rated or preset supply voltage when the laser device stops emitting light (under no-load or near-no-load light-load conditions). Therefore, for medical devices with large load changes such as emitting light and stopping light emission, it cannot meet the requirement of maintaining a stable supply voltage throughout the entire process of pulsed light emission mode.
[0108] To address the limited gain adjustment capability of resonant converter circuits, a surge mode is employed to further adjust the gain for supply voltage regulation. Specifically, when the circuit is unloaded, if the supply voltage exceeds a preset upper threshold, the pulse is blocked, causing the supply voltage to drop. If the supply voltage falls below the preset lower threshold, a series of surge pulses are continuously emitted to generate output power, thereby raising the supply voltage. This process is repeated. However, because the upper and lower thresholds differ significantly, this control mode still results in large voltage fluctuations, which negatively impacts the stable output of medical laser equipment. Therefore, it is unsuitable for use in medical laser devices.
[0109] However, the resonant converter circuit control method involved in the embodiments of this application controls the resonant converter circuit to enter different segment working modes depending on the different working stages of the laser device. When the laser device is started, the resonant converter circuit is controlled to enter the first segment working mode. After the laser device is in a relatively stable state, it enters the second segment working mode. At this time, the laser device can emit light normally. When the light emission state of the laser device changes, that is, when light emission stops, the resonant converter circuit is controlled to switch from the second segment working mode to the first segment working mode. In the first section operating mode, the upper and lower switching devices in each arm of the independently controlled resonant converter circuit operate in different duty cycle modes (adjustable duty cycle mode and preset fixed duty cycle mode). For the upper switching device, due to the controllability of the duty cycle adjustment, dynamic sliding-type smooth and continuous adjustment can be achieved. Unlike the surge mode, it does not require intermittent surge-type pulses for control. Therefore, it can adjust the supply voltage over a wider range while taking stability into account, thus maintaining the supply voltage smoothly at the preset supply voltage and improving the stability of the supply voltage of the laser device throughout the entire light output process.
[0110] You can refer to this. Figure 7 As shown, Figure 7 The diagram shows a comparison between the supply voltage of a laser device employing the resonant converter circuit control method of this application and the supply voltage of a laser device employing the surge mode resonant converter circuit control method. Figure 7 As can be seen, the resonant converter circuit control method in the embodiments of this application can smoothly control the gain of the resonant converter circuit, thereby ensuring that the power supply voltage of the laser device is stably maintained at the preset power supply voltage, thus improving the stability of the power supply voltage of the laser device throughout the entire light output process.
[0111] It should be understood that, although Figure 2 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 2 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.
[0112] In some embodiments, a laser therapy machine is also provided, the basic structure of which can be referred to as follows: Figure 1 The laser device 100 shown, that is, the laser therapy machine, may include at least a controller 110 and a resonant converter circuit 120. The controller 110 is configured to perform the steps of any one or more of the methods in the above embodiments. Specific details regarding the laser therapy machine can be found in the preceding description in the application scenario section, and will not be repeated here. Those skilled in the art will understand that… Figure 1 The structure shown is merely a block diagram of a portion of the structure related to the solution of this application and does not constitute a limitation on the laser device or laser therapy machine to which the method of this application is applied. A specific laser device or laser therapy machine may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.
[0113] In some embodiments, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, performs the following steps: in response to the laser device starting up, controlling the resonant converter circuit to enter a first-segment operating mode; wherein, in the first-segment operating mode, the operating frequency of the resonant converter circuit remains fixed, the upper switching devices in each arm of the resonant converter circuit operate in a duty cycle adjustable mode, and the lower switching devices in each arm of the resonant converter circuit operate in a preset fixed duty cycle mode; in response to the duty cycle of the upper switching devices being adjusted to a preset value, controlling the resonant converter circuit to enter a second-segment operating mode; and in response to the laser device stopping light emission, controlling the resonant converter circuit to switch from the second-segment operating mode back to the first-segment operating mode.
[0114] In some embodiments, when the computer program is executed by the processor, it further implements the following steps: in response to normal light output from the laser device, controlling the resonant conversion circuit to maintain the second segment operating mode.
[0115] In some embodiments, when the computer program is executed by the processor, it further implements the following steps: controlling the upper switching device to remain in the off state for a preset number of switching cycles, and controlling the lower switching device to be turned on intermittently with a preset fixed duty cycle.
[0116] In some embodiments, when the computer program is executed by the processor, it further performs the following steps: obtaining the voltage loop calculation value and the current loop calculation value of the resonant converter circuit; calculating the current duty cycle based on the voltage loop calculation value and the current loop calculation value; and adjusting the duty cycle of the upper switching device based on the current duty cycle.
[0117] In some embodiments, when the computer program is executed by the processor, it further implements the following steps: in the second segment operating mode, the duty cycle of the upper switching device and the duty cycle of the lower switching device are kept constant, and the operating frequency of the resonant converter circuit is adjusted.
[0118] In some embodiments, when the computer program is executed by the processor, it further performs the following steps: obtaining the voltage loop calculation value and the current loop calculation value of the resonant converter circuit; calculating the current operating frequency based on the voltage loop calculation value and the current loop calculation value; and adjusting the operating frequency of the resonant converter circuit based on the current operating frequency.
[0119] In some embodiments, when the computer program is executed by the processor, it further implements the following steps: in response to the operating frequency of the resonant converter circuit being adjusted to the highest operating frequency, obtaining the current output voltage of the resonant converter circuit and determining whether the current output voltage is greater than the rated voltage; in response to the current output voltage being greater than the rated voltage, controlling the resonant converter circuit to switch from the second segment operating mode to the first segment operating mode.
[0120] In some embodiments, when the computer program is executed by the processor, it further implements the following steps: controlling a first trigger pulse and a second trigger pulse respectively through a first comparison register and a second comparison register that are independent of each other; controlling a first switching device to operate in a duty cycle adjustable mode through the first trigger pulse, and controlling a second switching device to operate in a preset fixed duty cycle mode through the second trigger pulse.
[0121] In some embodiments, when the computer program is executed by the processor, it further implements the following steps: controlling a third trigger pulse and a fourth trigger pulse respectively through a third comparison register and a fourth comparison register that are independent of each other; wherein the third trigger pulse is out of phase with the first trigger pulse, and the fourth trigger pulse is out of phase with the second trigger pulse; controlling the third switching device to operate in a duty cycle adjustable mode through the third trigger pulse, and controlling the fourth switching device to operate in a preset fixed duty cycle mode through the fourth trigger pulse.
[0122] In some embodiments, when the computer program is executed by the processor, it further performs the following steps: independently setting a rising edge dead time in a first trigger pulse; and independently setting a falling edge dead time in a second trigger pulse.
[0123] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.
[0124] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0125] Furthermore, the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the characters in this article generally indicate that the preceding and following related objects have an "or" relationship.
[0126] In addition, the terms "first" and "second" used in this article are merely for distinguishing descriptions and are not used to limit priority, order, importance, etc.
[0127] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
[0128] It should be noted that, in the embodiments of this application, data related to user information or user data must be obtained and processed only after the user's authorization and consent. When the embodiments of this application are applied to specific products or technologies, user permission or consent is required, and the collection, use and processing of related data must comply with the relevant laws, regulations and standards of the relevant countries and regions.
Claims
1. A resonant converter circuit control method, applied to laser equipment, the method comprising: In response to the startup of the laser device, the resonant converter circuit is controlled to enter the first segment working mode; wherein, in the first segment working mode, the operating frequency of the resonant converter circuit remains fixed, the upper switching device in each bridge arm of the resonant converter circuit operates in the duty cycle adjustable mode, and the lower switching device in each bridge arm of the resonant converter circuit operates in the preset fixed duty cycle mode. In response to the duty cycle of the upper switching device being adjusted to a preset value, the resonant conversion circuit is controlled to enter the second segment operating mode; In response to the laser device stopping light emission, the resonant conversion circuit is controlled to switch from the second segment operating mode to the first segment operating mode.
2. The method according to claim 1, characterized in that, The method further includes: In response to the laser device emitting light normally, the resonant conversion circuit is controlled to maintain the second segment operating mode.
3. The method according to claim 1, characterized in that, Before the control resonant converter circuit enters the first segment operating mode, the method further includes: The upper switching device is controlled to remain in the off state for a preset number of switching cycles, and the lower switching device is controlled to be turned on intermittently with a preset fixed duty cycle.
4. The method according to claim 1, characterized in that, Before the duty cycle of the upper switching device is adjusted to a preset value, the method further includes: Obtain the calculated voltage loop and current loop values of the resonant converter circuit; Calculate the current duty cycle based on the voltage loop calculation value and the current loop calculation value; Adjust the duty cycle of the upper switching device according to the current duty cycle.
5. The method according to claim 1, characterized in that, After controlling the resonant converter circuit to enter the second segment operating mode, the method further includes: In the second section operating mode, the duty cycle of the upper switching device and the duty cycle of the lower switching device are kept constant, and the operating frequency of the resonant converter circuit is adjusted.
6. The method according to claim 5, characterized in that, Adjusting the operating frequency of the resonant converter circuit includes: Obtain the calculated voltage loop and current loop values of the resonant converter circuit; Calculate the current operating frequency based on the voltage loop calculation value and the current loop calculation value; The operating frequency of the resonant converter circuit is adjusted according to the current operating frequency.
7. The method according to claim 1, characterized in that, Before the method controls the resonant converter circuit to switch from the second segment operating mode to the first segment operating mode, the method further includes: In response to the operating frequency of the resonant converter circuit being adjusted to the highest operating frequency, the current output voltage of the resonant converter circuit is obtained, and it is determined whether the current output voltage is greater than the rated voltage. In response to the current output voltage being greater than the rated voltage, the resonant converter circuit is controlled to switch from the second segment operating mode to the first segment operating mode.
8. The method according to claim 1, characterized in that, The upper switching device includes a first switching device and a third switching device, and the lower switching device includes a second switching device and a fourth switching device; wherein... Controlling the upper switching devices in each bridge arm of the resonant converter circuit to operate in an adjustable duty cycle mode, and controlling the lower switching devices in each bridge arm of the resonant converter circuit to operate in a preset fixed duty cycle mode, includes: The first trigger pulse and the second trigger pulse are controlled by the independent first and second comparison registers, respectively. The pulse that controls the first switching device to operate in an adjustable duty cycle mode by the first trigger pulse, and controls the second switching device to operate in a preset fixed duty cycle mode by the second trigger pulse.
9. The method according to claim 8, characterized in that, The method further includes: The third and fourth trigger pulses are controlled by independent third and fourth comparison registers, respectively; wherein the third trigger pulse is out of phase with the first trigger pulse, and the fourth trigger pulse is out of phase with the second trigger pulse. The third trigger pulse controls the third switching device to operate in an adjustable duty cycle mode, and the fourth trigger pulse controls the fourth switching device to operate in a preset fixed duty cycle mode.
10. The method according to claim 8, characterized in that, The method further includes: A rising edge dead zone is independently set in the first trigger pulse; The falling edge dead zone is set independently in the second trigger pulse.
11. A laser therapy machine, characterized in that, It includes at least a controller and a resonant converter circuit, wherein, The controller is configured to perform the steps of the method according to any one of claims 1 to 10.
12. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 10.