Multi-closed-loop parameter autonomous smooth switching control method based on load characteristic identification

Abstract

The invention discloses a multi-closed-loop parameter autonomous smooth switching control method based on load characteristic identification. A variable load, a load characteristic sampling unit, a bias superposition unit, a closed-loop reference given unit, a closed-loop switching unit, a closed-loop control unit and a power output unit are included. The load characteristic sampling unit transmits the acquired variable load circuit and other signals to the closed-loop switching unit after bias superposition of the bias superposition unit; the closed-loop switching unit performs phase operation on the bias superposed signal to obtain a corresponding power supply closed-loop control mode, and transmits the identified power supply closed-loop control mode to the closed-loop control unit; and the closed-loop control unit is used for switching a power supply closed-loop control mode by combining a closed-loop reference value output by the closed-loop reference giving unit so as to control the power output unit to output corresponding power to the variable load. According to the invention, through the self-generated conduction characteristics of the diodes, the hysteresis function can be realized without adding extra algorithms and circuits, and autonomous smooth switching can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply multi-closed-loop switching control, and in particular to a multi-closed-loop parameter autonomous smooth switching control method based on load characteristic identification. Background Art

[0002] Power supplies can be categorized by control mode as either open-loop or closed-loop. For most applications, closed-loop control is required due to load variations, interference, and precision requirements. A closed-loop control system, also known as a feedback control system, uses a feedback loop to monitor the system's actual output and compare it with the desired value, adjusting the control variable to achieve the desired goal. In addition to all the components of open-loop control, closed-loop control systems also include sensors and comparators. Based on the comparison results, the controller adjusts its output to minimize errors and achieve precise control. Closed-loop control power supplies typically utilize output current signals, output voltage signals, or other forms of energy converted into voltage and current signals for closed-loop control, and most are single-loop control systems.

[0003] For some special applications, such as nonlinear power supply controllers, this type of power supply controller needs to determine the working mode of the power supply based on the output load. Generally, there are three working modes: constant current working area, constant power working area, and constant voltage working area. A typical representative of this type of power supply is the ion pump power supply controller. Taking it as an example, the output characteristic requirements of its power supply controller are determined by the working characteristics of the ion pump. The ion pump in the initial state is equivalent to an extremely small load. At this time, it is a short-circuit working area for the power supply. The power supply needs to be able to output a constant current under short-circuit conditions. After working for a period of time, the equivalent load of the ion pump becomes larger. At this time, the power supply needs to be able to output at a constant power, that is, the output voltage needs to increase as the output current decreases. When the ion pump is completed, the ion pump is equivalent to an extremely large load. At this time, it is an open-circuit working area for the power supply. The power supply needs to be able to remain unchanged after reaching a certain output voltage. In such special applications, the power supply needs to be able to adjust the closed-loop mode during the output load change, that is, switch from the voltage-voltage closed-loop working mode to the current-current closed-loop working mode. Most current power supplies use single closed-loop control systems. Switching between different closed-loop modes requires complex control algorithms and circuits, which can affect the overall performance of the power supply. Furthermore, closed-loop control may also be required based on operating conditions. For example, in different temperature ranges, the corresponding closed-loop operating mode must be switched.

[0004] In the prior art, closed-loop control technology, based on error amplifiers, comparators, and control logic as core components, is widely used. The error amplifier compares the detected output signal with a reference signal and amplifies the error signal. The comparator compares the error signal with a predetermined threshold to control the switching frequency and duty cycle of the switching element. Furthermore, in most applications, simply controlling the output using a "switching variable" alone cannot maintain stability. This is because sensor speeds are not infinitely fast, and both data acquisition and control require time. Therefore, all closed-loop control systems typically incorporate additional algorithms, most commonly the PID closed-loop control algorithm. This algorithm adjusts the system output through proportional, integral, and differential calculations to achieve the desired control effect. The core of the PID algorithm is to calculate a control variable based on the current deviation (the difference between the target and actual values), as well as the historical accumulation and future trends of the deviation, to adjust the behavior of the controlled object. In closed-loop control power supplies, this is achieved by implementing a hardware PID controller that compares the feedback information value with the changing trend of a set reference value to perform closed-loop regulation. For some applications that need to switch between multiple closed-loop working modes according to the output load, it is usually necessary to add complex control algorithms and control circuits, as well as different PID parameters for different closed-loop working modes.

[0005] The prior art publication number CN115249000A proposes a novel lithium battery + supercapacitor hybrid energy storage topology and its control design method. Through the system transient assumption, a transient mean model of the lithium battery energy storage device regarding the duty cycle is constructed, thereby constructing a system control model, obtaining two sets of closed-loop control parameters, and determining the operating mode of the entire system by multiplying the voltage loop and current loop control parameters with the actual measured voltage and current error value. This can effectively improve the charging and discharging flexibility and reliability of the hybrid energy storage system, and achieve the control goals of not overcharging and discharging the lithium battery at an excessive rate and not over-voltage the bus voltage.

[0006] Prior art publication number CN222509098U proposes a flyback topology multi-channel constant-voltage power supply circuit with multiple transformers coupled in series. In the structure of the flyback circuit, a secondary transformer is cascaded to one of the flyback output branches and used for closed-loop control. In addition, the secondary closed-loop branch is coupled to another closed-loop branch on the primary side of the main transformer. Compared with traditional multi-closed-loop systems, this solves the problem of mutual influence between multiple cascaded closed-loop systems and the need for separate debugging. At the same time, the method of not requiring multiple ICs also greatly reduces the cost and volume of the flyback topology multi-channel constant-voltage circuit.

[0007] The above existing technologies have the following problems: (1) The multi-closed-loop operating mode switching control method is complex, requiring the calculation of closed-loop control parameters for different operating modes and the use of corresponding control algorithms to determine the current corresponding load conditions and switch to the corresponding operating mode, which has a certain delay. (2) The multi-closed-loop operating mode switching control circuit structure of the existing power supply is complex, requiring a special circuit structure or the introduction of additional branches for closed-loop control, which is relatively complex to implement. Summary of the Invention

[0008] 1. Technical problems to be solved: In response to the above technical problems, the present invention provides a multi-closed-loop parameter autonomous smooth switching control method based on load characteristic identification to solve the core problem of closed-loop mode switching design of power supplies in special application scenarios. In this method, based on the clamping characteristics of the diode, the closed-loop value is autonomously and smoothly switched through the common cathode diode. When the load changes dynamically, the output sampling information will change accordingly. At this time, all sampling information will be compared through the diode common cathode structure, and the largest one will be used as the sampling value for closed-loop operation. That is, when the working area changes, the dominant sampling information will switch accordingly, thereby realizing autonomous and smooth switching of the closed-loop mode. This will help to develop power closed-loop control methods in special application fields, simplify closed-loop switching control methods, and promote the development of related power supplies. 2. Technical solution: An autonomous smooth switching method for multi-objective closed-loop parameters of a power supply based on load characteristics is used to achieve autonomous smooth switching of the power supply between multiple closed-loop modes. The method is characterized by including a variable load, a load characteristic sampling unit, a bias superposition unit, a closed-loop reference setting unit, a closed-loop switching unit, a closed-loop control unit and a power output unit.

[0009] The load characteristic sampling unit transmits the collected variable load circuit and other signals to the closed-loop switching unit after bias superposition through the bias superposition unit; the closed-loop switching unit calculates the bias superposition signal to obtain the corresponding power closed-loop control mode, and transmits the corresponding dominant control signal of the identified power closed-loop control mode to the closed-loop control unit; the closed-loop control unit switches the power closed-loop control mode in combination with the closed-loop reference value output by the closed-loop reference setting unit, and then controls the power output unit to output the corresponding power to the variable load.

[0010] Furthermore, the circuit signals in the circuit and other signals of the variable load include voltage signals and current signals; the other signals are signals related to the working state of the variable load; the signals related to the working state of the variable load include temperature and pressure signals; the circuit and other signals of the variable load serve as target control parameters of the power closed-loop control mode.

[0011] Furthermore, the load characteristic sampling unit converts the collected circuit signal into a digital signal and transmits it to the bias superposition unit.

[0012] Furthermore, the bias superposition unit is composed of multiple sub-units; each sub-unit includes two operational amplifiers, wherein the first operational amplifier serves as a non-inverting adder operator, and its input end is connected to the output end of the load characteristic sampling unit; the second operational amplifier is invertingly connected to the feedback resistor of the non-inverting adder operator; the signal after superposition by its corresponding sub-unit is transmitted to the closed-loop switching unit.

[0013] Furthermore, the closed-loop switching unit is composed of multiple diodes connected in parallel with a common cathode; the anode of each diode is connected to the sub-unit output end of its corresponding bias unit; the on-off state of the multiple parallel diodes determines the current corresponding power closed-loop control signal, and all are switched to the corresponding power closed-loop control mode through the same closed-loop control unit.

[0014] Furthermore, a bias adjustment resistor for adjusting the size of the sampling information is provided in the subunit of the bias superposition unit.

[0015] 3.Beneficial effects: (1) The multi-closed-loop parameter autonomous smooth switching control method based on load characteristic identification disclosed by the present invention can be realized by only using diodes. By matching the voltage level of the sampling circuit, the multi-target closed-loop parameters can be autonomously realized, such as the voltage loop and the current loop, to achieve smooth switching. The structure is simple and can effectively simplify the multi-closed-loop switching control of the power supply.

[0016] (2) The multi-closed-loop parameter autonomous smooth switching control method based on load characteristic identification disclosed in the present invention can achieve rapid switching response of the sampling signal as the output working condition changes by reasonably dividing the working area according to the boundaries of the dominant parameters corresponding to the working modes under different loads. The control loop switches to another control loop on the basis of a certain working state of normal operation. The adjustment change of the controlled parameters (such as duty cycle, frequency, etc.) is small, and the target switching loop can quickly establish a steady-state working point. The entire system can achieve an ideal loop switching response speed to meet some specific application requirements.

[0017] (3) The multi-closed-loop parameter autonomous smooth switching control method based on load characteristic identification disclosed in the present invention can achieve stable operation of multiple closed-loop working modes without changing the closed-loop compensator loop parameters, whether it is the hardware PID compensator parameters or even the digital PID compensator parameters, and without redesigning the PID parameters, thereby further simplifying the control loop design of the multi-objective parameter closed-loop system.

[0018] (4) The multi-closed-loop parameter autonomous smooth switching control method based on load characteristic identification disclosed in the present invention can achieve an increase in the number of closed loops by increasing the number of diodes and reasonably dividing the working area. For example, within a wide range of working point changes, target control parameters such as voltage loop, current loop, and power loop can be achieved in different working point areas.

[0019] (5) In the multi-closed-loop parameter autonomous smooth switching control method based on load characteristic identification disclosed in the present invention, a fixed bias voltage value U is additionally added on the basis of the sampled voltage values ​​of different target closed-loop parameters. bias , ensuring that there is always one diode in the common cathode diode in the on state, avoiding the process where the sampling circuit output voltage amplitude is too low and the diode cannot be stably turned on normally.

[0020] In summary, the power supply closed-loop mode autonomous smooth switching control method proposed in this method based on load characteristic identification can have a hysteresis function and realize autonomous smooth switching through the self-generated conduction voltage drop of the diode without adding additional algorithms and circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the autonomous smooth switching control structure of the power closed-loop control mode of the present invention; Figure 2 Schematic diagram of the circuit structure of the closed-loop switching unit and the bias superposition unit in the present invention; Figure 3 This is the load characteristic curve of the ion pump used in the verification example; Figure 4 To verify the output waveform of different characteristic loads under static load in the example; Figure 5 This is the structural diagram of the dynamic load test platform built in the verification example; Figure 6 To verify the power supply output waveform under dynamic load in the example; Figure 7 This is the output waveform of the power supply under continuously changing load conditions in the verification example. DETAILED DESCRIPTION

[0022] The present invention will be described in detail below with reference to the accompanying drawings.

[0023] As attached Figure 1 、 2 As shown, an autonomous smooth switching method for multi-objective closed-loop parameters of a power supply based on load characteristics is used to achieve autonomous smooth switching of the power supply between multiple closed-loop modes, and is characterized by including a variable load, a load characteristic sampling unit, a bias superposition unit, a closed-loop reference setting unit, a closed-loop switching unit, a closed-loop control unit and a power output unit.

[0024] The load characteristic sampling unit transmits the collected variable load circuit and other signals to the closed-loop switching unit after bias superposition through the bias superposition unit; the closed-loop switching unit calculates the bias superposition signal to obtain the corresponding power closed-loop control mode, and transmits the corresponding dominant control signal of the identified power closed-loop control mode to the closed-loop control unit; the closed-loop control unit switches the power closed-loop control mode in combination with the closed-loop reference value output by the closed-loop reference setting unit, and then controls the power output unit to output the corresponding power to the variable load.

[0025] Furthermore, the circuit signals in the circuit and other signals of the variable load include voltage signals and current signals; the other signals are signals related to the working state of the variable load; the signals related to the working state of the variable load include temperature and pressure signals; the circuit and other signals of the variable load serve as target control parameters of the power closed-loop control mode.

[0026] Furthermore, the load characteristic sampling unit converts the collected circuit signal into a digital signal and transmits it to the bias superposition unit.

[0027] Furthermore, the bias superposition unit is composed of multiple sub-units; each sub-unit includes two operational amplifiers, wherein the first operational amplifier serves as a non-inverting adder operator, and its input end is connected to the output end of the load characteristic sampling unit; the second operational amplifier is invertingly connected to the feedback resistor of the non-inverting adder operator; the signal after superposition by its corresponding sub-unit is transmitted to the closed-loop switching unit.

[0028] Furthermore, the closed-loop switching unit is composed of multiple diodes connected in parallel with a common cathode; the anode of each diode is connected to the sub-unit output end of its corresponding bias unit; the on-off state of the multiple parallel diodes determines the current corresponding power closed-loop control signal, and all are switched to the corresponding power closed-loop control mode through the same closed-loop control unit.

[0029] Furthermore, a bias adjustment resistor for adjusting the size of the sampling information is provided in the subunit of the bias superposition unit.

[0030] Circuit working principle: As attached Figure 1As shown, the power controller of the autonomous smooth switching method of the multi-objective closed-loop parameters using the present method mainly consists of a power output unit, a variable load, a load characteristic sampling unit, a closed-loop reference setting unit, a closed-loop switching unit and a closed-loop control unit, wherein the closed-loop switching unit is the core of the autonomous smooth switching control of the power closed-loop control mode. When the load changes, the load output characteristics will also change accordingly. The information of the change, including voltage signal, current signal and other signals, will be given to the closed-loop reference setting unit and the closed-loop switching unit respectively through the load characteristic sampling unit. The closed-loop reference setting unit will give the corresponding closed-loop reference value according to the load characteristics, and all the sampling information will be calculated in the closed-loop switching unit. As the feedback is fed back to the closed-loop control unit, the closed-loop control unit will adjust to the corresponding working mode, control the power unit to output the corresponding power, and realize smooth switching under different closed-loop modes.

[0031] Attachment Figure 2 This is the specific circuit structure of the bias superposition unit and the closed-loop switching unit. It primarily consists of a common-direction adder circuit and multiple diodes with a common cathode. Its primary function is to bias-superimpose and compare the sampled information from the load characteristic sampling unit. R1-R5 in the figure are bias adjustment resistors used to adjust the sampled information. All sampled information, after bias superposition, enters the closed-loop switching unit for comparison. In the figure, n represents the number of closed-loop control parameters corresponding to the circuit. When the voltage of u1 is at its maximum, due to the unidirectional conduction and clamping characteristics of the diodes, only diode D1 conducts, while all other diodes are off. The closed-loop switching unit outputs u1, and the circuit operates in closed-loop control mode 1, where the closed-loop value is the output voltage, achieving a regulated output voltage. When the load characteristics change, requiring a switch in the closed-loop control mode, the voltage of u2 reaches its maximum value, and the closed-loop switching unit outputs u2, switching the circuit to closed-loop mode 2, where the closed-loop value is the output current, achieving a regulated output current. The switching process for other closed-loop values ​​is similar. Finally, the critical values ​​of each working mode are overlapped at the dividing point, so that a very simple circuit structure can be used to achieve smooth switching between different closed-loop working modes.

[0032] Feasibility experiment verification example: In this feasibility experiment, an ion pump is used as the output load, and its load characteristic curve is shown in the attached figure. Figure 3 As shown in the figure, the ion pump's load characteristics require two closed-loop operating modes. Upon power-up, the ion pump requires the power supply to output a constant current of 100mA. After a period of power-up, the ion pump requires the power supply to output both constant power and constant voltage. This characteristic requirement requires the power supply to be able to switch between voltage and current loops. The power supply experimental platform uses a high-voltage DC power supply with programmable output.

[0033] 1. Experimental verification of the feasibility of normal operation of different closed-loop modes under static load First, we verify that this control method can achieve autonomous and smooth switching of the power supply closed-loop working mode under static load. Output experiments are carried out with fixed resistance loads of 10kΩ, 20kΩ, and 50kΩ. The corresponding closed-loop working areas are the current loop working area, the current loop-voltage loop boundary point, and the voltage loop working area. The actual output voltage and output current waveforms are measured using a voltage probe and a current probe respectively. The output waveform is as follows: Figure 4 As shown in the figure, according to the ion pump characteristic curve, under equivalent load conditions of 10kΩ, 20kΩ, and 50kΩ, the ideal output is 100mA, 100mA / 2kV, and 3.1kV. As can be seen from the waveform diagram, the actual measured values ​​are 100mA, 100mA / 2kV, and 3kV, which are consistent with the ideal situation. Therefore, under static load conditions, the diode power supply closed-loop control mode autonomous smooth switching control method using this method can achieve normal switching between different closed-loop modes.

[0034] 2. Experimental verification of the feasibility of switching between different closed-loop modes under dynamic load conditions Secondly, verify that this method can realize autonomous and smooth switching of the closed-loop working mode of the power supply under dynamic load. Use high-voltage relays to change the output load value when the power supply is operating normally, and create a dynamically changing load condition to verify the feasibility of this control method. Connect two series resistors of 10kΩ and 40kΩ respectively to the output end, and connect a high-voltage relay to the 40kΩ to control whether the resistor is connected to the circuit, thereby forming a dynamically changing load of 10kΩ and 50kΩ, that is, the corresponding power closed-loop control mode switches from current loop closed-loop control to voltage loop closed-loop control. The specific circuit structure is as follows Figure 5 shown.

[0035] The specific circuit structure is as follows Figure 5 As shown, first open the high voltage relay, then R 2 is short-circuited, the output equivalent load is 10kΩ, and the power supply starts to work normally. At this time, the high-voltage relay is turned off, and the equivalent load becomes 50kΩ. Finally, the high-voltage relay is turned on again, and the equivalent load returns to 10kΩ. That is, the power supply closed-loop control mode goes through the switching process of current loop closed-loop control, voltage loop closed-loop control, and current loop closed-loop control. The test waveform obtained in this verification experiment is as follows Figure 6 As shown in the figure, even under dynamic loads, the power supply can switch between the current loop and the voltage loop as the load changes, and the switching speed is very fast. This confirms that under dynamic load conditions, the autonomous and smooth switching control method of the diode power supply closed-loop control mode using this method can achieve normal switching between different closed-loop modes.

[0036] 3. Experimental verification of the feasibility of closed-loop operating mode switching under continuously changing load conditions Finally, we verify that this solution can achieve smooth switching of the closed-loop control mode of the power supply under continuously changing load conditions. The ion pump is tested for startup. During the startup process of the ion pump, the power supply output load is a continuously changing dynamic load. The test output voltage waveform is shown in the attached figure. Figure 7 As shown in the figure, when the pump is first started, the power supply operates in the current loop, outputting a constant current of 100mA. As the pump starts, the equivalent load of the ion pump gradually increases. When the equivalent load reaches 20kΩ, the boundary between the power supply's current loop and voltage loop is reached. The voltage and current waveforms show no obvious switching traces, and the power supply then enters the voltage loop mode, with the output current gradually decreasing and the output voltage gradually increasing. Throughout the pump start-up process, even under continuously varying load conditions, the diode power supply closed-loop control method employing this method can still switch normally between different closed-loop modes without noticeable switching traces, achieving autonomous and smooth switching.

[0037] Although the present invention has been disclosed above in terms of preferred embodiments, they are not intended to limit the present invention. Anyone skilled in the art can make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection defined by the claims of this application.

Claims

1. A multi-closed-loop parameter autonomous smooth switching control method based on load characteristic identification is used to achieve autonomous smooth switching of a power supply between multiple closed-loop modes, characterized by: It includes a variable load, a load characteristic sampling unit, a bias superposition unit, a closed-loop reference setting unit, a closed-loop switching unit, a closed-loop control unit and a power output unit; The load characteristic sampling unit transmits the collected variable load circuit and other signals to the closed-loop switching unit after bias superposition through the bias superposition unit; the closed-loop switching unit calculates the bias superposition signal to obtain the corresponding power closed-loop control mode, and transmits the corresponding dominant control signal of the identified power closed-loop control mode to the closed-loop control unit; the closed-loop control unit switches the power closed-loop control mode in combination with the closed-loop reference value output by the closed-loop reference setting unit, and then controls the power output unit to output the corresponding power to the variable load.

2. The multi-closed-loop parameter autonomous smooth switching control method based on load characteristic identification according to claim 1 is characterized in that: The circuit signals in the circuit and other signals of the variable load include voltage signals and current signals; other signals are signals related to the working state of the variable load; the signals related to the working state of the variable load include temperature and pressure signals; the circuit and other signals of the variable load serve as target control parameters of the power closed-loop control mode.

3. The multi-closed-loop parameter autonomous smooth switching control method based on load characteristic identification according to claim 2 is characterized in that: The load characteristic sampling unit converts the collected circuit signal into a digital signal and transmits it to the bias superposition unit.

4. The multi-closed-loop parameter autonomous smooth switching control method based on load characteristic identification according to claim 3 is characterized in that: The bias superposition unit is composed of multiple subunits; each subunit includes two operational amplifiers, wherein the first operational amplifier serves as a non-inverting adder operator, and its input end is connected to the output end of the load characteristic sampling unit; the second operational amplifier is invertedly connected to the feedback resistor of the non-inverting adder operator; the signal after superposition by its corresponding subunit is transmitted to the closed-loop switching unit.

5. The multi-closed-loop parameter autonomous smooth switching control method based on load characteristic identification according to claim 4 is characterized in that: The closed-loop switching unit is composed of multiple diodes connected in parallel with a common cathode; the anode of each diode is connected to the output end of the sub-unit of its corresponding bias unit; the on-off state of the multiple parallel diodes determines the current corresponding power closed-loop control signal, and all are switched to the corresponding power closed-loop control mode through the same closed-loop control unit.

6. The multi-closed-loop parameter autonomous smooth switching control method based on load characteristic identification according to claim 5 is characterized in that: The subunit of the bias superposition unit is provided with a bias adjustment resistor for adjusting the size of the sampling information.

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