Topology method and system capable of improving printer power supply utilization rate and storage medium

Abstract

The invention discloses a topological method and system capable of improving the utilization rate of a printer power supply and a storage medium. A non-isolated / isolated Buck-Boost topological circuit composed of four MOS tube groups is adopted as a main power conversion architecture; according to the method, input and output voltage and current are collected in real time through an ADC, and intelligent control is executed by an MCU: according to an input and output voltage comparison result, three working modes of Buck, Boost or direct connection are automatically switched, so that high efficiency is kept in a full range; a self-adaptive PID (Proportion Integration Differentiation) control algorithm is adopted, for example, overshoot is suppressed by variable step size integration, surge current is prevented by double-loop amplitude limiting soft start, and electromagnetic interference is suppressed by input current ripple feedforward; in addition, the system also has optimization strategies such as light load mode consumption reduction, load sudden change pre-compensation and dynamic dead zone time adjustment, and the system correspondingly comprises an acquisition module, a control module, a power conversion module and the like; according to the invention, the problems of unstable voltage and low efficiency of the printer power supply caused by ripple and load abrupt change are solved, and the power supply utilization rate and the printing quality are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of printer switching power supply, and particularly relates to a topology method, system and storage medium capable of improving the utilization rate of a printer power supply. BACKGROUND

[0002] The existing printer usually adopts a switching power supply or a linear power supply with a fixed output voltage. However, the load characteristics of the printer are extremely special, and the power consumption is quite different in different working states such as standby, printhead movement, and heater starting, which causes the power load to frequently and sharply jump. Such load mutation will cause the instantaneous drop or overshoot of the power output voltage, that is, the so-called ripple and noise. A larger power ripple will directly interfere with the accurate control of the inkjet of the print head, resulting in quality problems such as garbled code and stripes in printing.

[0003] To solve this problem, the existing technology usually adopts a scheme of increasing the output capacitance value or using a linear voltage stabilizer for secondary filtering. However, the former increases the size and cost of the power supply, and has limited effect on low-frequency disturbance suppression. The latter is low in efficiency when bearing a large current, and generates a lot of heat, thereby reducing the service life of the power supply.

[0004] In addition, when the mains voltage fluctuates or different specifications of power adapters are used, a fixed topology structure such as a single Buck or Boost cannot maintain high-efficiency voltage stabilization in a wide input voltage range. For example, CN115395787A Power Supply Topology Circuit, Power Supply Control Method, Electronic Device and Storage Medium discloses a topology integrating PFC and Buck, but it can only realize step-down conversion and cannot work when the input voltage is lower than the required output voltage.

[0005] Another scheme such as CN115955113A Three-port DC-DC Converter adopts a complex multi-tube topology to realize bidirectional power flow, but its control strategy is not optimized for the impact of the capacitive load of the printer, and the efficiency is low at light load. In addition, there is an efficiency dip point when the input and output voltages are close, and the single voltage feedback loop cannot effectively suppress the input current ripple, which has a high risk of electromagnetic interference.

[0006] Therefore, there is an urgent need in the field for a printer power supply solution that can adapt to a wide range of voltage inputs, efficiently suppress the impact of load mutation, and reduce ripple noise, in order to improve the printing quality and the reliability of the power supply. SUMMARY

[0007] In order to overcome the problems of the prior art, the present application discloses a topology method, system and storage medium capable of improving the utilization rate of a printer power supply.

[0008] To solve the above technical problems, the technical scheme of the present application is as follows:

[0009] A topology method capable of improving the power utilization rate of a printer, comprising the following steps:

[0010] When the switching power supply is turned on, the ADC acquisition module acquires the input voltage Vin and the output voltage Tout, and uploads the acquired data to the upper computer through the micro control unit MCU for real-time display;

[0011] The output voltage Tout and the output current are stably output by switching the MOS tube groups Q1, Q2, Q3 and Q4 through the switching of the input voltage Vin and the input current, wherein the four MOS tube groups Q1, Q2, Q3 and Q4 form a buck-boost topology circuit, and satisfy the formula:

[0012] Tout=D / (1-D)*Vin

[0013] Wherein, Tout is the output voltage, D is the duty ratio, and Vin is the input voltage;

[0014] The micro control unit MCU runs the motor PID control algorithm, and adjusts the voltage size by modifying the kp proportional coefficient, ki integral coefficient, kd differential coefficient and ks anti-integral saturation coefficient in the PID control algorithm online, to realize soft start;

[0015] The printer performs printing work, the output voltage Tout changes when the nozzle voltage is adjusted, and the input voltage is maintained at 220V stable input through the buck-boost topology;

[0016] The buck-boost topology circuit is a non-isolated structure, and when overcurrent and overvoltage occur, the original circuit is connected in series through the bootstrap boost module for power supply;

[0017] The duty ratio D is dynamically adjusted through the PID control algorithm to realize soft start and stable tracking.

[0018] Preferably, the operation steps of the buck-boost topology circuit comprise:

[0019] When the input voltage Vin is greater than the output voltage Tout, work in Buck step-down mode;

[0020] When the input voltage Vin is equal to the output voltage Tout, Q1 and Q4 are turned on, and Q2 and Q3 are turned off;

[0021] When the input voltage Vin is less than the output voltage Tout, work in Boost step-up mode.

[0022] Preferably, the integral coefficient ki in the PID control algorithm is adaptively adjusted according to the output voltage deviation:

[0023] The integral coefficient ki is set to a second value by default during the power-on initialization of the micro control unit MCU;

[0024] When the absolute value of the difference between the output voltage Tout and the target output voltage Vin is greater than a first preset threshold, the integral coefficient ki is set to a first value;

[0025] When the absolute value is less than or equal to the first preset threshold, the integral coefficient ki is restored to the second value;

[0026] The first value is less than the second value.

[0027] Preferably, the method further comprises a light load control step:

[0028] The output current is monitored;

[0029] When the output current is lower than a second preset threshold, the MOS transistor group is switched from the forced continuous conduction mode to the pulse skip mode to reduce the light load power consumption.

[0030] Preferably, the method further comprises an input current ripple suppression step:

[0031] The ripple voltage on the equivalent series resistance of the input capacitor is collected;

[0032] The differential value of the ripple voltage is used as a feedforward compensation amount, which is superimposed on the output amount of the PID control algorithm to suppress the switching frequency ripple of the input current.

[0033] Preferably, the method further comprises a load mutation pre-compensation step:

[0034] The load device enable signal from the printer is received;

[0035] When the activation edge of the enable signal is detected, the target output voltage Vin is temporarily raised by a predetermined offset, and the offset is cancelled after a predetermined time.

[0036] Preferably, the step of controlling the switching state of the MOS transistor group further comprises dead time control:

[0037] The absolute value of the difference between the input voltage Vin and the output voltage Tout is calculated;

[0038] The dead time applied between the complementary MOS transistor group pairs is dynamically adjusted according to the absolute value, wherein the dead time and the absolute value have a positive correlation.

[0039] Preferably, the soft start process is realized by double-loop limiting:

[0040] The outer loop limits the rising slope of the output voltage to be no more than a first slope threshold;

[0041] The inner loop limits the output current rise slope to no more than the second slope threshold.

[0042] The output of a PID control algorithm is limited by the smaller of the outputs of the outer loop and the inner loop.

[0043] Preferably, a topology system for improving printer power utilization, used to implement a topology method for improving printer power utilization, includes:

[0044] The ADC acquisition module is used to acquire input voltage Vin, input current, output voltage Tout, and output current.

[0045] The microcontroller unit (MCU) is connected to the ADC acquisition module and is configured to execute the PID control algorithm and generate PWM control signals.

[0046] The power conversion module includes MOSFET groups Q1, Q2, Q3, and Q4, which are connected in a buck-boost topology.

[0047] The auxiliary power supply module provides operating voltage for the microcontroller unit (MCU) and the drive circuit in the power conversion module.

[0048] The auxiliary power supply module includes:

[0049] The bootstrap boost module is connected in series for power supply during overcurrent and overvoltage conditions;

[0050] The switching power supply module converts 220V to 12V and divides the voltage to supply other components on the circuit board.

[0051] Preferably, a non-volatile storage medium stores a computer program that, when executed by a processor, implements the topology method that can improve printer power utilization.

[0052] The beneficial effects of this invention are as follows:

[0053] Thanks to the adoption of a four-switch Buck-Boost topology and its intelligent mode switching algorithm, this invention enables the printer power supply to automatically select the optimal Buck, Boost, or pass-through mode to operate under a wide range of input voltage fluctuations, ensuring stable output under any operating conditions. This avoids the problem of low efficiency at specific operating points in traditional single topologies. Especially when the input and output voltages are close, the pass-through mode reduces switching losses, improves overall power efficiency, reduces heat accumulation, and effectively extends the service life of the power supply box.

[0054] This invention improves dynamic response and output voltage quality. Through a series of targeted control algorithms, it suppresses power disturbances that cause print quality problems. Adaptive PID control and load mutation pre-compensation technology work together to quickly and smoothly cope with impact loads such as printhead heating, effectively suppressing voltage drops and overshoots, and ensuring a continuous and stable voltage for the printhead. Secondly, the input current ripple feedforward suppression technology reduces switching noise and conduction electromagnetic interference from the source. These measures work together to solve problems such as garbled characters and stripes in printing caused by insufficient power ripple and transient response.

[0055] To achieve efficient operation across the entire load range and meet energy-saving and environmental protection requirements, this invention introduces a light-load pulse cross-cycle modulation mode. When the printer is in standby or under light load, the system automatically switches to this mode, reducing the number of switching and drive losses, keeping standby power consumption at a low level, meeting strict energy regulations, and achieving green energy saving.

[0056] Dual-loop limiting soft start eliminates the impact of power-on surge current on the switching transistor and input power supply by simultaneously limiting the rise rate of voltage and current; adaptive dead-time control dynamically optimizes the dead time while ensuring that shoot-through between the upper and lower transistors is prevented, reducing the risk and loss caused by reverse recovery of the body diode, and further improving the robustness of the system.

[0057] In summary, this invention is not a simple circuit improvement, but a systematic solution that integrates advanced topology, intelligent control, and multiple optimization strategies. It effectively overcomes the inherent defects of existing printer power supply technology and brings improvements in efficiency, stability, reliability, and print quality. Attached Figure Description

[0058] Figure 1 The flowchart illustrates the steps of a topology method for improving printer power utilization according to Embodiment 1 of the present invention.

[0059] Figure 2 A schematic diagram of a buck-boost topology circuit for a topology method that can improve printer power utilization provided in Embodiment 1 of the present invention;

[0060] Figure 3 This is a schematic diagram of a system that can improve the power utilization of a printer, as provided in Embodiment 1 of the present invention. Detailed Implementation

[0061] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, exemplary embodiments will be described in detail below, examples of which are illustrated in the accompanying drawings. In the following description relating to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of methods and systems consistent with some aspects of this application as detailed in the appended claims.

[0062] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0063] The following detailed description of the specific implementation methods, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided in detail.

[0064] Example 1

[0065] Please see Figure 1 A topology method for improving printer power utilization includes the following steps:

[0066] When the switching power supply is turned on, the ADC acquisition module acquires the input voltage Vin and the output voltage Tout, and uploads the acquired data to the host computer for real-time display via the microcontroller unit MCU.

[0067] The output voltage Tout and output current are stabilized by switching MOSFETs Q1, Q2, Q3, and Q4 through the switching of input voltage Vin and input current. The four MOSFETs Q1, Q2, Q3, and Q4 form a buck-boost topology and satisfy the following formula:

[0068] Tout = D / (1-D) * Vin

[0069] Where Tout is the output voltage, D is the duty cycle, and Vin is the input voltage;

[0070] The microcontroller unit (MCU) runs the motor PID control algorithm. By modifying the proportional coefficient (kp), integral coefficient (ki), derivative coefficient (kd), and anti-integral saturation coefficient (ks) in the PID control algorithm online, the voltage magnitude is adjusted to achieve soft start.

[0071] The microcontroller unit (MCU) uses a Renesas processor and has a built-in motor PID control algorithm, which can quickly process PID data and issue control commands.

[0072] When the printer is printing, the output voltage Tout changes when the printhead voltage is adjusted. The buck-boost topology maintains the input voltage at a stable 220V.

[0073] The buck-boost topology is a non-isolated structure. In the event of overcurrent or overvoltage, the original circuit is connected in series to supply power through the bootstrap module.

[0074] The duty cycle D is dynamically adjusted using a PID control algorithm to achieve soft start and stable tracking.

[0075] Furthermore, the operating steps of the buck-boost topology circuit include:

[0076] Buck buck mode:

[0077] When the input voltage Vin is detected to be greater than the output voltage Tout, the system automatically enters Buck buck mode. In Buck buck mode, switches Q1 and Q2 act as the main switching pair, performing complementary switching actions with a dead time inserted between them to prevent shoot-through. Switch Q3 remains off, and switch Q4 remains on, equivalent to synchronous rectifiers. The specific working process is as follows: during the period when Q1 is on and Q2 is off, the input power supply supplies power to the load through Q1 and inductor L, while simultaneously storing energy in inductor L. During the period when Q1 is off and Q2 is on, inductor L continues to release energy to the load through the freewheeling circuit formed by Q2 and Q4, maintaining a stable output voltage. This mode is suitable for operating conditions with high grid voltage or low load voltage requirements, and can effectively reduce losses.

[0078] Straight-through mode:

[0079] When the input voltage Vin is detected to be equal to the output voltage Tout, the system enters the shoot-through mode. In the shoot-through mode, the control signal keeps the switching transistors Q1 and Q4 continuously on while keeping the switching transistors Q2 and Q3 off. The input power supply is directly connected to the load almost without loss through the on-state Q1 and Q4. The current flowing through the inductor L is very small. The shoot-through mode eliminates switching losses and achieves high conversion efficiency when the input and output voltages are very close, effectively solving the problem of efficiency dip in traditional converters under this condition.

[0080] Boost Mode:

[0081] When the input voltage Vin < output voltage Tout is detected, the system automatically switches to Boost mode. In Boost mode, switches Q3 and Q4 act as the main switching pair to perform complementary switching actions, while switch Q1 remains on, which is equivalent to the input switch, and switch Q2 remains off.

[0082] During the period when Q3 is off and Q4 is on, the input power supply forms a loop through Q1 and inductor L to store energy in inductor L; during the period when Q3 is on and Q4 is off, the energy stored in the input power supply and inductor L is superimposed and supplied to the load and output capacitor through Q1 and Q3, thereby increasing the output voltage and ensuring that the system can still provide a stable output when the input voltage drops or the load requires a higher voltage.

[0083] The Boost mode switching is executed in real time by the microcontroller unit (MCU), such as the Renesas processor. The MCU continuously monitors Vin and Tout through the ADC acquisition module and compares them in the interrupt of each control cycle. Based on the comparison result, the PWM generator module of the MCU will immediately output four drive signals corresponding to the above modes to control the switching state of the switching transistors Q1-Q4, so as to achieve smooth and fast switching between modes.

[0084] Specifically, through the aforementioned three-mode intelligent switching mechanism, each module of the printer power supply can adapt to a wide range of input voltage fluctuations and load changes, always operating in the optimal topology state, thereby improving the overall efficiency of the power supply. Especially in the critical region of Vin=Tout, it enhances the adaptability to various complex working scenarios of the printer and ensures the quality and stability of the output power supply.

[0085] Furthermore, the integral coefficient ki in the PID control algorithm is adaptively adjusted based on the output voltage deviation:

[0086] The first preset threshold is the voltage deviation tolerance value, which can be set to 0.5V. It is used to determine whether the printer is in a rapid adjustment state with a large deviation.

[0087] The first value is the small value mode of the integral coefficient ki. For example, it can be set to 1 / 2 or 1 / 4 of the rated integral coefficient ki. Its function is to weaken the integral effect when there is a large deviation and prevent integral saturation.

[0088] The second value is the normal mode value of the integral coefficient ki, which is the rated integral coefficient used by the PID control algorithm during steady-state fine adjustment.

[0089] When the microcontroller unit (MCU) is powered on and initialized, the integral coefficient ki is set to the second value by default.

[0090] The deviation is calculated in real time. In each control cycle, such as every 100 microseconds, the microcontroller unit (MCU) calculates the absolute value of the difference between the current output voltage Tout and the target output voltage Vin.

[0091] In the case of large deviation, when the absolute value of the difference between the output voltage Tout and the target output voltage Vin is greater than the first preset threshold, the microcontroller unit (MCU) determines that the system is in a rapid adjustment process caused by sudden load changes, etc.; the MCU immediately switches the integral coefficient ki to the first value; a smaller ki value means that the integral action is slower, which effectively prevents the integral term from accumulating excessively during the rapid voltage pull-back process and avoids subsequent overshoot;

[0092] In the small deviation state, when the output voltage is successfully pulled back and the absolute value is less than or equal to the first preset threshold, the microcontroller unit (MCU) determines that the system has entered the steady-state fine adjustment stage. The MCU restores the integral coefficient ki to the second value. A larger ki value ensures that the system can quickly eliminate steady-state error and maintain high-precision stability of the output voltage.

[0093] Specifically, slow integration during large deviations prevents overshoot, while fast integration during small deviations ensures accuracy. This dynamic adjustment strategy resolves the conflict between speed and overshoot, making it particularly suitable for scenarios with drastic load changes, such as printers. It can suppress voltage fluctuations caused by sudden loads such as printhead start-up and shutdown, thereby directly improving print quality.

[0094] Furthermore, the specific implementation of the light-load control step is as follows:

[0095] The second preset threshold is a current threshold used to define the light load state. The second preset threshold is set according to the system standby power consumption target, such as 50mA. When the output current is lower than this value, the printer is considered to have entered the light load state.

[0096] The printer operates in forced continuous conduction mode by default. In this mode, the PWM signal is continuously output to ensure that the inductor current is adjusted in each switching cycle. It has a fast dynamic response, but low efficiency under light load.

[0097] Real-time monitoring: The microcontroller unit (MCU) continuously monitors the system's output current through the ADC acquisition module;

[0098] When the output current is detected to be less than the second preset threshold and remains so for a certain period of time, such as 10ms, after the microcontroller unit (MCU) determines that the system has entered a light load state, the MCU controls the PWM generator to switch the working mode of the MOS transistor group from the forced continuous conduction mode to the pulse cross-cycle modulation mode.

[0099] Pulse cross-cycle modulation mode operation mode:

[0100] In pulse-cycle modulation mode, the microcontroller unit (MCU) does not generate PWM pulses in every cycle. Instead, it first stops switching, turns off all MOSFETs, and only monitors the output voltage. When the output voltage drops to a lower threshold due to load consumption, the MCU will re-enable the PWM generator, generate a short burst of dense pulses, quickly raise the output voltage to a higher threshold, and then stop switching again, repeating this cycle.

[0101] The repetition frequency of the pulse is positively correlated with the load size. The lighter the load, the slower the output voltage drops. The longer the pulse interval, the fewer the switching times, and the lower the losses.

[0102] When the microcontroller unit (MCU) detects that the output current is greater than the second preset threshold, it indicates that the load has increased. If the printer starts to warm up, it will immediately exit the pulse cross-cycle modulation mode and switch back to the forced continuous conduction mode to ensure sufficient dynamic response speed.

[0103] Specifically, by employing a forced continuous conduction mode during heavy-load to normal-load conditions to ensure performance, and automatically switching to a pulse cross-cycle modulation mode during light-load to standby conditions to optimize efficiency, the inherent losses of traditional power supplies under light load conditions are avoided. This dual-mode hybrid control mechanism enables the printer to maintain high efficiency across the entire load range.

[0104] Furthermore, it also includes an input current ripple suppression step:

[0105] The input capacitor, usually an electrolytic capacitor or multiple ceramic capacitors connected in parallel, has an inherent parameter—equivalent series resistance. When an input current containing switching frequency ripple flows through the capacitor, a ripple voltage with the same phase and frequency as the ripple current is generated across the equivalent series resistance. The ripple voltage can also be obtained by multiplying the input current ripple by the equivalent series resistance; that is, by acquiring the ripple voltage, information about the input current ripple can be indirectly obtained.

[0106] In terms of hardware layout, one differential input port of the ADC acquisition module is directly connected to both ends of the input capacitor, specifically for acquiring the high-frequency ripple voltage on the input capacitor;

[0107] Differential processing involves the microcontroller unit (MCU) performing differential calculations on the ripple voltage sampled in each control cycle, or implementing this in hardware using a high-speed differential amplifier, to obtain the differential value of the ripple voltage. The result of the differential operation reflects the changing trend of the input current ripple.

[0108] Gain adjustment involves multiplying the differentiated signal by a programmable feedforward gain coefficient to adjust the differentiated signal to a suitable amplitude. The value of the programmable feedforward gain coefficient needs to be determined experimentally to ensure that the compensation amount matches the actual interference amount.

[0109] Superposition compensation uses the differential signal after gain adjustment as the feedforward compensation amount and directly superimposes it onto the main duty cycle control signal calculated by the PID control algorithm. This operation is manifested as a simple addition operation in the digital controller.

[0110] The feedforward compensation essentially provides a correction signal that is opposite to the trend of the input current switching frequency ripple. When the input current tends to increase, the compensation will reduce the duty cycle in advance to suppress the current rise; when the input current tends to decrease, the compensation will increase the duty cycle in advance to suppress the current decrease; thus forming an active and timely cancellation effect to smooth the input current.

[0111] Specifically, by using differential feedforward, the traditional single-loop voltage feedback control is upgraded to a composite control with input disturbance look-ahead compensation. This method can effectively suppress input current ripple without adding expensive current sampling sensors, reduce the peak level of conducted electromagnetic interference from the source, and simplify the design of back-end filters.

[0112] Furthermore, it also includes a load mutation pre-compensation step:

[0113] The load mutation pre-compensation step requires communication with the printer's main control system. When the printer's main control board is about to turn on a high-power load device, such as a heating element, it will send an enable signal to the execution entity of the load mutation pre-compensation, namely the microcontroller unit (MCU), through a general input / output pin or serial communication interface. The transition of the enable signal from invalid to valid is the activation edge.

[0114] The predetermined offset is a voltage boost value determined based on historical data or experiments, used to compensate for expected voltage drops, and can be set to 3% to 5% of the target output voltage;

[0115] The predetermined time is the duration of the voltage rise, which is slightly longer than the time it takes for the load device to start up and for the current to stabilize.

[0116] The microcontroller unit (MCU) continuously monitors the specified input / output pins or parses serial communication interface instructions, waiting for the enable signal;

[0117] Once the microcontroller unit (MCU) detects the activation edge of the enable signal, it immediately enters the pre-compensation state; the MCU temporarily adds a predetermined offset to the current target output voltage Vin' based on the target output voltage Vin.

[0118] The microcontroller unit (MCU) starts an internal timer. Within a predetermined time, the PID control algorithm adjusts the output voltage Vin' based on the new, higher target output voltage, causing the output voltage Vin to rise in advance. When the timer expires, the MCU restores the target voltage to the original target output voltage Vin. At this time, the load device has started normally, its current demand tends to stabilize, and the power supply output voltage smoothly recovers to the standard value, thereby avoiding voltage drop.

[0119] Specifically, by receiving external event signals and proactively adjusting the control target in advance, this method can eliminate the output voltage drop caused by a sudden increase in high-power load, provide a stable operating voltage for precision loads such as the print head, and solve print quality problems caused by power supply ripple and insufficient transient response.

[0120] Furthermore, the steps for controlling the switching state of the MOSFET group also include dead-time control:

[0121] Dead time is used to allow one transistor in a complementary MOSFET pair to be completely turned off before the other transistor is turned on. During the turn-off process of the MOSFET, the body diode undergoes a reverse recovery process, generating peak current and noise. The input-output voltage difference directly affects the reverse recovery charge of the body diode and the slope of the switching node voltage change. The larger the voltage difference, the more severe these effects are, and the longer the required safe dead time is; conversely, the smaller the voltage difference, the shorter the dead time can be set.

[0122] The microcontroller unit (MCU) reads the current input voltage Vin and output voltage Tout, and calculates the absolute value of their difference ΔV = |Vin - Tout|;

[0123] The microcontroller unit (MCU) calculates the required adaptive dead time in real time according to the formula:

[0124] T dead =K*ΔV+Tmin

[0125] Where K is a programmable coefficient, a proportional coefficient that maps the voltage difference to the additional dead time required. The value of K is determined experimentally to balance safety and efficiency.

[0126] Tmin is the minimum dead time, which is a basic safety value. It is a dead time that must be guaranteed even when the voltage difference is zero, such as 40ns, to ensure the propagation delay of the drive circuit itself.

[0127] When the printer is lightly loaded and the input voltage Vin is approximately equal to the output voltage Tout, the absolute value ΔV is very small, and the adaptive dead time T... deadApproaching the minimum dead time Tmin reduces voltage errors and losses caused by dead time; when sudden load changes or mode switching cause the absolute value ΔV to increase, the adaptive dead time Tmin is adjusted. dead Automatically increases, providing sufficient safety margin;

[0128] The microcontroller unit (MCU) will calculate T dead The value is written to the dead time register of the internal PWM generator module in real time. The PWM generator will automatically insert the corresponding dead time into the complementary PWM signal generated next according to this new value.

[0129] To further optimize, the voltage of the switching node can be monitored during the dead time. For example, a comparator can be used to try to achieve zero-voltage switching. When the node voltage is detected to have reached its lowest point, the corresponding MOSFET group can be turned on, which can further reduce switching losses and electromagnetic interference.

[0130] Specifically, the dead time is transformed from a fixed, conservative safety parameter into an intelligent parameter that dynamically optimizes based on the circuit voltage difference. This provides sufficient protection when the voltage difference is large and the risk is high, while pursuing maximum efficiency when the voltage difference is small and the operating conditions are mild, thereby enhancing system reliability and avoiding shoot-through risks. By minimizing unnecessary dead time, the power supply's conversion efficiency, output voltage accuracy, and electromagnetic interference performance are improved, making it particularly suitable for scenarios with frequently changing operating states, such as printer power supplies.

[0131] Furthermore, the soft-start process is achieved through dual-loop limiting:

[0132] In addition to the voltage control loop of the standard PID control algorithm, two independent slope-limiting loops are constructed in parallel:

[0133] The outer loop, or voltage slope loop, is implemented using an independent slope function generator, which generates a slope starting from zero and starting with a first slope threshold dV / dt. set Such as a voltage ramp value that rises linearly at 0.5V / ms;

[0134] The inner loop, or current slope loop, monitors the output current in real time through the ADC acquisition module and calculates the current change rate dI / dt; the independent slope limiting loop is set with a second slope threshold dI / dt. set For example, 0.5 A / ms limits the rate of change of current;

[0135] First slope threshold dV / dt set The maximum allowable rise slope of the output voltage ensures a smooth voltage build-up.

[0136] Second slope threshold dI / dt set The maximum allowable rise slope of the output current directly limits the charging current to the output capacitor, thereby suppressing surge current.

[0137] When the system receives the start command, the output of the PID control algorithm is cleared to zero, the voltage ramp generator starts to rise linearly from 0V, and the current slope limiter is ready.

[0138] The voltage loop is equal to the current ramp voltage value;

[0139] Current loop = previous cycle output command + second slope threshold * ΔTt;

[0140] Wherein, ΔTt is the control period, but this command value is constrained by the actual current feedback;

[0141] Input both the voltage loop and the current loop into the minimum selector simultaneously;

[0142] The smaller of the output voltage loop and current loop of the minimum selector is used as the upper limit of the duty cycle D of the PID control algorithm output;

[0143] During the initial startup phase, the current required to charge the capacitor is large, and the current loop is usually smaller than the voltage loop. The printer's startup speed is dominated by the current slope loop, which strictly limits the rate of change of current dI / dt to avoid surge current.

[0144] As the output voltage gradually builds up and the charging current decreases, the voltage loop becomes smaller than the current loop; the printer's startup speed is then dominated by the voltage slope loop to ensure that the voltage reaches the target value smoothly.

[0145] When the voltage ramp value reaches and remains at the target output voltage Vin, the soft start process ends and the printer enters the normal voltage regulation mode.

[0146] Specifically, by introducing a parallel dual-loop structure arbitrated by the minimum selector, it ensures that the printer automatically follows the more conservative rising slope of either voltage or current at all times; it eliminates inrush current, protects power devices, and prevents system instability or external device disconnection caused by power-on surges. It is particularly suitable for power supply systems with large capacitive loads, such as printers, thereby improving product reliability and user experience.

[0147] Furthermore, a topology system that can improve printer power utilization includes:

[0148] The ADC acquisition module is used to acquire input voltage Vin, input current, output voltage Tout, and output current.

[0149] The ADC acquisition module is usually integrated inside the microcontroller unit (MCU). It acquires the system's input voltage Vin, input current, output voltage Vout, and output current in real time through an external voltage sampling resistor divider network and current sampling resistor, or Hall sensor, and converts these analog quantities into digital quantities for the control module to process.

[0150] The microcontroller unit (MCU), typically a Renesas processor, is configured to execute PID control algorithms and generate PWM control signals in order to connect to the ADC acquisition module.

[0151] The microcontroller unit (MCU) internally incorporates the motor PID control algorithm, as well as advanced control logic such as adaptive variable integral coefficient, light load mode switching, and feedforward compensation.

[0152] The microcontroller unit (MCU) calculates and generates four PWM control signals with adjustable dead time in real time based on the data from the ADC acquisition module and the preset algorithm, which directly drive the MOSFETs in the power conversion module.

[0153] The power conversion module includes MOSFETs Q1, Q2, Q3, and Q4, which are connected in a buck-boost topology.

[0154] The power conversion module is the core of the system's energy conversion. It consists of four MOSFETs Q1, Q2, Q3, and Q4, a power inductor L, and input and output filter capacitors, forming a four-switch Buck-Boost topology circuit. Under the control of the microcontroller unit (MCU), the Buck-Boost topology circuit can flexibly operate in Buck, Boost, or shoot-through modes according to the relationship between the input voltage Vin and the output voltage Vout, achieving wide-range and high-efficiency voltage conversion.

[0155] An auxiliary power supply module provides operating voltage for the microcontroller unit (MCU) and the drive circuits in the power conversion module.

[0156] The auxiliary power supply module includes:

[0157] The bootstrap boost module provides power in series during overcurrent and overvoltage conditions; it provides a floating power supply for the gate drive of high-side switches Q1 and Q3 that require the switching node voltage as a reference point, ensuring that they can be reliably turned on and off.

[0158] The switching power supply module is responsible for converting the 220V AC mains power into a stable low-voltage DC power such as 12V to power the drive circuit of the power conversion module and other parts of the system.

[0159] After the system is powered on, the auxiliary power module works to supply power to the microcontroller unit (MCU) and the drive circuit. After the MCU starts up, it executes the dual-loop limiting soft-start program to smoothly establish the output voltage. During normal operation, the MCU continuously monitors electrical parameters and intelligently switches working modes, adjusts control parameters, injects feedforward compensation, responds to load changes, and optimizes dead time, thereby dynamically maintaining the extreme stability of the output voltage.

[0160] Specifically, by coordinating four modules—data acquisition, control, power, and auxiliary—it solves problems such as unstable power supply voltage, low efficiency, and slow response in traditional printers, improves power utilization, and provides a solid foundation for high-quality printing.

[0161] This method can be implemented using a computer-readable storage medium containing a computer program that, when executed by a processor, implements the aforementioned topology method for improving printer power utilization.

Claims

1. A topology method for improving printer power utilization, characterized in that, Includes the following steps: When the switching power supply is turned on, the ADC acquisition module acquires the input voltage Vin and the output voltage Tout, and uploads the acquired data to the host computer for real-time display via the microcontroller unit MCU. The output voltage Tout and output current are stabilized by switching MOSFETs Q1, Q2, Q3, and Q4 through the switching of input voltage Vin and input current. The four MOSFETs Q1, Q2, Q3, and Q4 form a buck-boost topology and satisfy the following formula: Tout = D / (1-D) * Vin Where Tout is the output voltage, D is the duty cycle, and Vin is the input voltage; The microcontroller unit (MCU) runs a motor PID control algorithm. By modifying the proportional coefficient (kp), integral coefficient (ki), derivative coefficient (kd), and anti-integral saturation coefficient (ks) in the PID control algorithm online, the voltage magnitude is adjusted to achieve soft start. When the printer is printing, the output voltage Tout changes when the printhead voltage is adjusted. The buck-boost topology maintains the input voltage at a stable 220V. The buck-boost topology is a non-isolated structure. In the event of overcurrent or overvoltage, the original circuit is connected in series to supply power through the bootstrap module. The duty cycle D is dynamically adjusted using a PID control algorithm to achieve soft start and stable tracking.

2. The topology method for improving printer power utilization according to claim 1, characterized in that, The operation steps of the buck-boost topology circuit include: It operates in Buck buck mode when the input voltage Vin > the output voltage Tout; When the input voltage Vin = the output voltage Tout, Q1 and Q4 are turned on, and Q2 and Q3 are turned off. It operates in Boost mode when the input voltage Vin is less than the output voltage Tout.

3. The topology method for improving printer power utilization according to claim 1, characterized in that, The integral coefficient ki in the PID control algorithm is adaptively adjusted based on the output voltage deviation. When the microcontroller unit (MCU) is powered on and initialized, the integral coefficient ki is set to the second value by default. When the absolute value of the difference between the output voltage Tout and the target output voltage Vin is greater than the first preset threshold, the integral coefficient ki is set to the first value; When the absolute value is less than or equal to the first preset threshold, the integral coefficient ki is restored to the second value; Wherein, the first value is less than the second value.

4. The topology method for improving printer power utilization according to claim 1, characterized in that, It also includes light load control steps: Monitor output current; When the output current is lower than the second preset threshold, the MOS transistor group is controlled to switch from the forced continuous conduction mode to the pulse cross-cycle modulation mode to reduce the power consumption under light load.

5. The topology method for improving printer power utilization according to claim 1, characterized in that, It also includes an input current ripple suppression step: The ripple voltage across the equivalent series resistance of the input capacitor is collected. The derivative of the ripple voltage is used as a feedforward compensation amount and superimposed on the output of the PID control algorithm to suppress the switching frequency ripple of the input current.

6. The topology method for improving printer power utilization according to claim 1, characterized in that, It also includes a load mutation pre-compensation step: Receive the load device enable signal from the printer; When the activation edge of the enable signal is detected, the target output voltage Vin is temporarily increased by a predetermined offset, and the offset is canceled after a predetermined period of time.

7. The topology method for improving printer power utilization according to claim 1, characterized in that, The steps for controlling the switching state of the MOSFET group also include dead time control: Calculate the absolute value of the difference between the input voltage Vin and the output voltage Tout; The dead time applied between complementary MOS transistor pairs is dynamically adjusted based on the absolute value, wherein the dead time is positively correlated with the absolute value.

8. The topology method for improving printer power utilization according to claim 1, characterized in that, The soft-start process is achieved through dual-loop limiting: The outer loop limits the output voltage rise slope to not exceed the first slope threshold. The inner loop limits the output current rise slope to no more than the second slope threshold. The output of the PID control algorithm is limited by the smaller of the outputs of the outer loop and the inner loop.

9. A topology system for improving printer power utilization, used to implement the topology method for improving printer power utilization as described in any one of claims 1-8, characterized in that, include: The ADC acquisition module is used to acquire input voltage Vin, input current, output voltage Tout, and output current. The microcontroller unit (MCU) is connected to the ADC acquisition module and is configured to execute the PID control algorithm and generate PWM control signals. The power conversion module includes MOSFETs Q1, Q2, Q3, and Q4, which are connected in a buck-boost topology. An auxiliary power supply module provides operating voltage for the microcontroller unit (MCU) and the drive circuits in the power conversion module. The auxiliary power supply module includes: The bootstrap boost module is connected in series for power supply during overcurrent and overvoltage conditions; The switching power supply module converts 220V to 12V and provides voltage divider for other components on the circuit board.

10. A non-volatile storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the topology method according to any one of claims 1-8 that can improve the power utilization of the printer.

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