High-frequency special power resonance point avoidance control system and method

Abstract

The application discloses a high-frequency special power resonance point avoidance control system and method, and relates to the field of special power control. The system comprises a power supply unit, a first current collection unit for collecting a first current signal flowing through a parasitic inductor, a second current collection unit for collecting a second current signal flowing to a load, a voltage collection unit for collecting a load end voltage signal, a virtual damping compensation module for multiplying a difference between the first current signal and the second current signal by a virtual damping coefficient to obtain a damping voltage, and then summing the damping voltage with the load end voltage signal to obtain a feedback voltage, and a voltage control module for comparing and adjusting the feedback voltage with a reference voltage. By introducing a virtual damping voltage at the control algorithm level, a virtual resistor is equivalent to being connected in series with the capacitor, the resonance peak value is reduced, the phase is improved from step lag to smooth transition, the system stability and robustness are improved, and physical devices need not be added to avoid heat loss.

Description

Technical Field

[0001] This invention relates to the field of special power supply control, specifically to a high-frequency special power supply resonant point avoidance control system and method. Background Technology

[0002] High-frequency special power supplies are power electronic devices with high-efficiency output characteristics, operating in the range of 100kHz to 10MHz. They are widely used in electromagnetic compatibility testing, radio frequency power amplification, plasma excitation, and power electronic converter testing. With the development of power electronics technology and the increasing demands of applications, higher requirements are being placed on the output frequency range, dynamic response speed, and system stability of high-frequency special power supplies.

[0003] In practical applications of high-frequency special power supplies, parasitic inductance exists in the connection lines between the power supply output and the load, and the load itself also has equivalent capacitance characteristics. These parasitic inductances and the load's equivalent capacitance constitute an LC resonant network. When the power supply's operating frequency approaches the inherent resonant frequency of this LC network, the gain curve of the system's open-loop transfer function rises sharply near the resonant frequency, forming a significant resonant peak, while a step hysteresis of nearly 180 degrees appears in the phase. This resonance phenomenon causes the output voltage or power supply noise to be significantly amplified near the resonant frequency, severely reducing the system's phase margin and gain margin, posing a serious challenge to the stability of the control system, and affecting the power supply's output performance and the safe operation of the load.

[0004] To suppress LC resonance, existing technologies typically employ optimized hardware design to reduce parasitic inductance and capacitance. For example, parasitic inductance can be reduced by shortening connection lengths, using multi-strand parallel-wound wires, and optimizing PCB layout; capacitance parameters can be adjusted by selecting loads with low capacitance characteristics and adding decoupling capacitors. However, under high-frequency operating conditions, even with optimized hardware design, the impact of parasitic parameters is still drastically amplified, and the scope for hardware optimization is very limited, making it difficult to fundamentally eliminate the resonance problem.

[0005] Another existing technical solution is to connect passive devices in series or parallel in the LC resonant network, such as... Figure 1As shown, the resonant peak value or resonant frequency can be reduced by changing the system's impedance characteristics. This method adjusts the system's frequency response characteristics by adding physical components, which can suppress resonance to some extent. However, passive components inserted in series or parallel absorb the resonant peak energy and convert it into heat during operation, resulting in power loss, reduced overall system efficiency, and additional phase shift. Furthermore, the parameters of the added physical components are fixed at one time. When system operating conditions or load parameters change, the fixed-parameter components cannot adaptively adjust, leading to a decrease in resonance suppression effect and poor system flexibility and adaptability.

[0006] In summary, existing technologies for suppressing high-frequency power supply LC resonance suffer from limitations such as limited hardware optimization space, the introduction of additional power consumption and heat due to the addition of physical damping devices, and poor adaptability. Summary of the Invention

[0007] The purpose of this invention is to provide a control system and method for avoiding resonance points in high-frequency special power supplies, so as to solve the technical problems of poor system stability and weak robustness caused by the sharp increase in gain and phase step lag of the parasitic LC network between the output terminal and the load of high-frequency special power supplies near the resonance frequency. At the same time, it avoids the heat loss and lack of flexibility caused by traditional passive device solutions.

[0008] To achieve the above objectives, the present invention employs the following technical solution:

[0009] A high-frequency special power supply resonant point avoidance control system includes a power supply unit and further includes:

[0010] There is a parasitic inductance and a load-side capacitive element between the output terminal and the load terminal of the power supply unit. The parasitic inductance and the load-side capacitive element form an LC resonant network.

[0011] The first current acquisition unit is used to acquire the first current signal flowing through the parasitic inductor. ;

[0012] The second current acquisition unit is used to acquire the second current signal flowing to the load. ;

[0013] The voltage acquisition unit is used to acquire the voltage signal at the load end. ;

[0014] The virtual damping compensation module is used to adjust the voltage based on the first current signal. Second current signal and voltage signal Calculate the feedback voltage Specifically, for the first current signal With the second current signal Perform a difference calculation, and compare the difference signal with the virtual damping coefficient. Multiply to obtain the damping voltage, and then combine the damping voltage with the load terminal voltage signal. The feedback voltage is obtained by performing a summation operation. ;

[0015] The voltage control module is used to compare the feedback voltage with the reference voltage. Compare and adjust.

[0016] Furthermore, it also includes:

[0017] A voltage RMS loop module is used to output the reference voltage;

[0018] The inner current loop module is used to receive the output of the voltage control module and perform current regulation.

[0019] Furthermore, the voltage control module includes an error calculation unit and a proportional-integral controller. The error calculation unit is used to calculate the error signal between the feedback voltage and the reference voltage, specifically by calculating the difference between the reference voltage and the feedback voltage as the error signal.

[0020] A method for controlling resonant points in a high-frequency special power supply is applied to a power supply system including a power supply unit, parasitic inductance from the output terminal to the load terminal, and a load. The method includes steps such as acquiring the load terminal voltage signal, comparing the voltage signal with a reference voltage, and adjusting it. It also includes the following steps:

[0021] Acquire the first current signal flowing through the parasitic inductor ;

[0022] Acquire the second current signal flowing to the load. ;

[0023] Perform a difference calculation on the first current signal and the second current signal;

[0024] Compare the difference signal with the virtual damping coefficient Multiply them to obtain the damping voltage;

[0025] The feedback voltage is obtained by summing the damping voltage and the load terminal voltage signal. ;

[0026] The feedback voltage With reference voltage The comparison is performed to obtain the error signal;

[0027] The error signal is proportional-integral (PI) adjusted to output a control signal.

[0028] Furthermore, the sampling frequency of the first current signal, the second current signal, and the load terminal voltage signal is greater than or equal to 10 times the operating frequency.

[0029] Furthermore, it also includes:

[0030] The step of generating the reference voltage through the voltage RMS loop specifically involves acquiring the output voltage RMS value, comparing the output voltage RMS value with the voltage RMS set value, and outputting the reference voltage after proportional-integral adjustment.

[0031] Furthermore, it also includes:

[0032] The step of regulating the current through the inner current loop specifically involves comparing the control signal with the current limit value, and limiting the amplitude of the control signal when the current exceeds the current limit value.

[0033] The advantages of this invention are:

[0034] (1) By collecting the difference between the current flowing through the parasitic inductor and the current flowing to the load, the difference is multiplied by the virtual damping coefficient and added to the load voltage to form a feedback voltage. At the control algorithm level, this is equivalent to connecting a virtual resistor in series with the capacitor to achieve a damping effect. The resonant peak value is reduced from 150dB to 10.1dB, a reduction of 93.3%. The phase is improved from a step lag of 180 degrees to a smooth transition from 0 degrees to -180 degrees, eliminating phase abrupt changes and significantly improving system stability and robustness.

[0035] (2) Virtual damping is achieved by using software algorithms, without the need to add physical RLC devices, avoiding the heat loss caused by the absorption of resonance peak energy by the devices, achieving zero physical loss, and the system efficiency is not affected. Moreover, the virtual damping coefficient can be flexibly adjusted by software without replacing physical devices or changing the hardware circuit topology. The implementation cost is low, adaptable to different working conditions and load conditions, and the system has strong flexibility and adaptability. It can be applied to high-frequency special power supply systems with different power levels and frequency ranges, and has high engineering value.

[0036] (3) Even if there are output voltage fluctuations or noise near the resonant frequency, the output will not change drastically. Even if the system parameters change, the phase will not change suddenly. The system robustness is improved, and the contradiction between efficiency and stability of high-frequency special power supplies is fundamentally solved. Attached Figure Description

[0037] Figure 1 A circuit connection diagram for methods to avoid resonance points in traditional series or parallel passive devices;

[0038] Figure 2 This is a structural block diagram of the high-frequency special power supply resonant point avoidance control system of the present invention;

[0039] Figure 3 This is a block diagram illustrating the principle of the virtual damping compensation module and voltage control module of the present invention.

[0040] Figure 4 This is a schematic diagram of the equivalent circuit of the high-frequency special power supply resonant point avoidance control method of the present invention;

[0041] Figure 5 This is a schematic diagram comparing the Bode plots before and after processing using the high-frequency special power supply resonant point avoidance control method of the present invention. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that the virtual damping coefficient refers to the equivalent damping parameter introduced in the control algorithm, with the unit being Ω, and does not correspond to physical physical components.

[0043] Example 1

[0044] This embodiment provides a basic implementation method for a high-frequency special power supply resonant point avoidance control system and method, including a virtual damping coefficient. The value is 1Ω.

[0045] Please refer to Figure 2 The high-frequency special power supply resonant point avoidance control system includes a power supply unit, a first current acquisition unit, a second current acquisition unit, a voltage acquisition unit, a virtual damping compensation module, and a voltage control module. The power supply unit is a high-frequency special power supply with an operating frequency of 500kHz, an output voltage range of 0~100V, and a maximum output current of 10A. The output terminal of the power supply unit is connected to the load under test (EUT) via a connecting line, and the parasitic inductance of the connecting line is L. W The value is 10 μH. The tested load EUT has an internal equivalent capacitance C. EUT The value is 100nF. According to the LC resonant frequency calculation formula, the system's natural resonant frequency is calculated to be 159kHz.

[0046] The first current acquisition unit uses a Hall current sensor, with its input connected in series with the output of the power supply unit and the parasitic inductance L. W Between, used to collect the current flowing through parasitic inductance L W First current signal The output of the first current acquisition unit is connected to the first input of the virtual damping compensation module.

[0047] The second current acquisition unit uses a Hall current sensor, with its input terminal connected in series with the parasitic inductance L. W A second current signal is used to acquire the current flowing to the load under test (EUT) between the EUT and the load under test. The output of the second current acquisition unit is connected to the second input of the virtual damping compensation module.

[0048] The voltage acquisition unit uses a resistor divider circuit, with its input terminal connected in parallel across the load under test (EUT) to acquire the load terminal voltage signal. The output of the voltage acquisition unit is connected to the third input of the virtual damping compensation module.

[0049] Please refer to Figure 3 The virtual damping compensation module includes a subtractor, a multiplier, and an adder. The positive input of the subtractor is connected to the output of the first current acquisition unit to receive the first current signal. The negative input terminal of the subtractor is connected to the output terminal of the second current acquisition unit to receive the second current signal. The subtractor applies the first current signal. With the second current signal Perform difference calculation and output the difference signal. The output of the subtractor is connected to the first input of the multiplier. The second input of the multiplier receives the virtual damping coefficient. The multiplier multiplies the difference signal by the virtual damping coefficient and outputs the damped voltage. The output of the multiplier is connected to the first input of the adder. The second input of the adder is connected to the output of the voltage acquisition unit to receive the load voltage signal. The adder will dampen the voltage. With load terminal voltage signal Perform a summation operation and output the feedback voltage. The output of the adder is connected to the negative input of the voltage control module.

[0050] The working principle of the virtual damping compensation module is as follows: First current signal For the parasitic inductance L W The current, the second current signal The current flowing to the load under test (EUT) is calculated according to Kirchhoff's current law, which states that the current flows through the equivalent capacitance C of the load. EUT The current is That is, capacitance C EUT The charging and discharging current. The difference signal. Multiply by virtual damping coefficient The damping voltage was then obtained. This is equivalent to the capacitor current flowing through the virtual resistor. The resulting voltage drop. Damping voltage. With load terminal voltage The feedback voltage is obtained by adding them together. At the control algorithm level, this is equivalent to the capacitance C. EUT A virtual resistor was connected in series. Please refer to Figure 4 In the processed equivalent circuit, capacitor C EUT A virtual resistor was connected in series. The system's equivalent damping increases.

[0051] The voltage control module is a voltage instantaneous value loop, which includes an error calculation unit and a proportional-integral controller. The error calculation unit is a subtractor, and its positive input receives the reference voltage. The negative input terminal receives the feedback voltage output from the virtual damping compensation module. The error calculation unit calculates the reference voltage. With feedback voltage The error signal between them, the error signal is The output of the error calculation unit is connected to the input of the proportional-integral (PI) controller. The PI controller performs proportional-integral adjustment based on the error signal and outputs a control signal, which is used to control the output of the power supply unit.

[0052] The operation of this embodiment is as follows: Initially, the power supply unit output voltage is 50V and the load current is 5A. When the power supply unit output frequency approaches the system's inherent resonant frequency of 159kHz, without virtual damping control, the LC resonant network will exhibit resonance at the resonant frequency, causing the open-loop transfer function gain to rise sharply to 150dB at the resonant frequency, with a phase step lag of 180 degrees. Using the virtual damping control method of this invention, the virtual damping compensation module acquires the first current signal in real time. Second current signal and load terminal voltage signal The feedback voltage is calculated. The feedback voltage includes a virtual damping voltage, which is equivalent to the voltage across capacitor C. EUT A virtual resistor Rd is connected in series. The virtual resistor Rd increases the system's damping and suppresses the resonance phenomenon of the LC resonant network. The voltage control module will feed back the voltage. With reference voltage The signal is compared and adjusted by the proportional-integral controller to output a control signal, which controls the output of the power supply unit to achieve closed-loop control.

[0053] Please refer to Figure 5 A comparison of Bode plots before and after processing shows that, without virtual damping control (before processing), the system's open-loop transfer function has a peak gain of 150 dB at the resonant frequency of 159 kHz, and the phase exhibits a step lag of 180 degrees at the resonant frequency. After applying virtual damping control (after processing), the peak gain of the system's open-loop transfer function at the resonant frequency of 159 kHz is reduced to 10.1 dB, a reduction of 93.3%. The phase characteristic is improved from a step lag of 180 degrees to a smooth transition from 0 degrees to -180 degrees, eliminating the phase abrupt change.

[0054] from Figure 5 As can be seen, after adopting the virtual damping control method in this invention, the resonant peak value is reduced from 150dB to 10.1dB, and the resonant peak value is significantly flattened. The phase curve is improved from a step jump from 0 degrees to -180 degrees at the resonant frequency before processing to a smooth transition near the resonant frequency after processing, gradually changing from 0 degrees to -180 degrees. The amplitude-frequency response curve is flat after processing, and the phase-frequency response curve is continuous. The system has good dynamic characteristics near the resonant frequency. Even if there are output voltage fluctuations or noise near the resonant frequency, the output will not change drastically, meeting the stability requirements. Even if the system parameters change, the phase will not suddenly change drastically, and the system robustness is improved.

[0055] Example 2

[0056] The difference between this embodiment and Embodiment 1 is that a voltage RMS loop module and a current inner loop module are added to form a complete three-loop control system, and the virtual damping coefficient and proportional-integral controller parameters are optimized.

[0057] Please refer to Figure 2 The voltage RMS loop module is used to output a reference voltage. It acquires the RMS value of the power supply unit's output voltage, compares it with the set RMS voltage value, and outputs the reference voltage after adjustment by the proportional-integral controller. The output of the voltage RMS loop module is connected to the positive input of the voltage control module.

[0058] The inner current loop module receives the output from the voltage control module and regulates the current. It compares the control signal from the voltage control module with the current limit value. When the current exceeds the limit, it limits the amplitude of the control signal, thus implementing current limiting protection. The current limit value is set to 12A. When the load current exceeds 12A, the inner current loop module limits the control signal to the amplitude corresponding to 12A current, preventing overcurrent in the power supply unit. The output of the inner current loop module is connected to the control input of the power supply unit.

[0059] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high frequency special power evading resonance point control system comprising a power supply unit, characterized in that, Also comprising: There is a parasitic inductance and a load-side capacitive element between the output end of the power supply unit and the load end, and the parasitic inductance and the load-side capacitive element constitute an LC resonance network; a first current collection unit, configured to collect a first current signal flowing through the parasitic inductance ; A second current acquisition unit is configured to acquire a second current signal flowing to the load ; A voltage acquisition unit is configured to acquire a load end voltage signal ; The virtual damping compensation module is used to adjust the voltage based on the first current signal. Second current signal and voltage signal Calculate the feedback voltage Specifically, for the first current signal With the second current signal Perform a difference calculation, and compare the difference signal with the virtual damping coefficient. Multiply to obtain the damping voltage, and then combine the damping voltage with the load terminal voltage signal. The feedback voltage is obtained by performing a summation operation. ; a voltage control module for comparing said feedback voltage with a reference voltage and adjusting.

2. The high frequency special power evading resonant point control system according to claim 1, characterized in that, Also comprising: A voltage effective value loop module for outputting the reference voltage; A current inner loop module for receiving the output of the voltage control module and performing current regulation.

3. The high frequency special power evading resonant point control system of claim 1, wherein, The voltage control module comprises an error calculation unit and a proportional integral controller, and the error calculation unit is used to calculate the error signal between the feedback voltage and the reference voltage, specifically to calculate the difference between the reference voltage and the feedback voltage as the error signal.

4. A high-frequency special power resonance point avoidance control method, applied to a power supply system comprising a power supply unit, an output end to load end parasitic inductance and a load, the method comprising the steps of collecting a load end voltage signal, comparing the voltage signal with a reference voltage and adjusting, characterized in that, Also comprising the following steps: collecting a first current signal flowing through the parasitic inductance ; collecting a second current signal flowing to the load ; Difference operation is performed on the first current signal and the second current signal; multiplying the difference signal with a virtual damping coefficient to obtain a damping voltage; summing the damping voltage with the load end voltage signal to obtain a feedback voltage ; comparing the feedback voltage to a reference voltage to obtain an error signal; The error signal is subjected to proportional integral adjustment to output a control signal.

5. The high-frequency special power resonance point control method of claim 4, wherein, The sampling frequency of the first current signal, the second current signal and the load end voltage signal is greater than or equal to 10 times the working frequency.

6. The high-frequency special power resonance point control method of claim 4, wherein, Also comprising: The step of generating the reference voltage through the voltage effective value loop, specifically collecting the output voltage effective value, comparing the output voltage effective value with the voltage effective value set value, and outputting the reference voltage after proportional integral adjustment.

7. The high-frequency special power resonance point control method of claim 6, wherein, Also comprising: The step of current regulation through the current inner loop, specifically comparing the control signal with the current amplitude limiting value, and limiting the amplitude of the control signal when the current exceeds the current amplitude limiting value.

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