High-frequency variable-load high-voltage direct-current ripple power supply control method and system

Abstract

The invention discloses a high-frequency variable-load high-voltage direct-current ripple power supply control method and system, and the method comprises the steps: extracting a voltage waveform of a ripple generator as a feedback signal of a ripple voltage instantaneous value ring through the mixed sampling of the output of the ripple generator and a measured object end; the ripple voltage effective value of the measured object end is extracted to serve as feedback of a ripple voltage effective value ring, so that the ripple voltage effective value ring and a ripple voltage instantaneous value ring are formed, and the problems that in the prior art, ripple control precision is low, and load adaptability is poor are solved.

Description

Technical Field

[0001] The present invention relates to the field of electric vehicle high voltage system testing, and in particular to a high frequency variable load high voltage direct current ripple power supply control method and system. Background Art

[0002] The high-voltage system test of electric vehicles requires a high-voltage DC ripple power supply as the test equipment. The test system is a combination of AC and DC, and the AC ripple frequency is high. It is usually sensitive to changes in system parasitic inductance such as transformer leakage inductance, cable equivalent inductance, and the capacitance and inductance of the object being tested, which also brings certain challenges to the control of system ripple accuracy.

[0003] High-voltage DC ripple power supplies usually couple high-frequency ripple to DC voltage through transformer coupling. Because a large amount of DC current flows through its secondary side and the winding is relatively thick, it is difficult to reduce the leakage inductance of this transformer. This leakage inductance and load capacitance form a parasitic LC filter, causing the ripple output from the ripple generator to the end of the object under test to have a serious phase shift and amplitude change. In addition, the equivalent inductance of the cable between the high-voltage DC ripple power supply and the object under test, and the difference in capacitance between different objects under test will bring serious challenges to the control accuracy and stability of the ripple.

[0004] One of the existing technologies is ripple open-loop control. The ripple amplitude accuracy is very low, making it difficult to achieve the expected test effect. The other is a closed-loop control system. The existing closed-loop control system cannot simultaneously overcome the impact of phase shift and amplitude change on the system. Load changes can easily cause system instability and have poor load adaptability.

[0005] Based on the above problems existing in the prior art in this field, a high-frequency variable load high-voltage DC ripple power supply control method is proposed. Summary of the invention

[0006] The object of the present invention is to provide a high-frequency variable-load high-voltage DC ripple power supply control method and system, which can solve the problems of low ripple control accuracy and poor load adaptability in the prior art.

[0007] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0008] A high-frequency variable load high-voltage direct current ripple power supply control method adopts mixed sampling of a ripple generator output and a measured object end, extracts the effective value of the ripple voltage at the measured object end as feedback of the ripple voltage effective value loop, extracts the voltage waveform of the ripple generator as feedback signal of the ripple voltage instantaneous value loop, thereby forming a ripple voltage effective value loop and a ripple voltage instantaneous value loop, controls the ripple voltage amplitude at the measured object end through the ripple voltage effective value loop, controls the frequency and phase of the ripple generator output voltage through the ripple voltage instantaneous value loop, and outputs a sinusoidal modulation wave sin_pi of the ripple generator.

[0009] Furthermore, the calculation method of the sinusoidal modulated wave sin_pi includes the steps of collecting the voltage at the end of the measured object, extracting the effective value Urms_back through the effective value extraction module, subtracting the static error of Urms_back from the load end ripple voltage set value Urms_set after adjustment by the G1 controller and multiplying it with a set sinusoidal wave, and the output value obtained after subtracting the static error of the ripple generator output voltage sampling value Uo_back is adjusted by the G2 controller to output the sinusoidal modulated wave sin_pi.

[0010] Furthermore, the sine wave is set to sin2πft, where f is the load-end ripple voltage frequency.

[0011] A high-frequency variable-load high-voltage direct current ripple power supply control system includes a high-voltage direct current power supply, a ripple generator, a coupling transformer, a measured object and a ripple generator modulation unit, wherein the ripple generator modulation unit includes:

[0012] A first voltage sampling module, a second voltage sampling module, an effective value extraction module, a ripple voltage effective value loop, and a ripple voltage instantaneous value loop, wherein the input end of the first voltage sampling module is connected to the ripple voltage at the end of the measured object, the output end of the first voltage sampling module is connected to the input end of the effective value extraction module, the output end of the effective value extraction module is connected to the input end of the ripple generator modulation unit, the input end of the second voltage sampling module is connected to the output end of the ripple generator, and the output end of the second voltage sampling module is connected to the other input end of the ripple generator modulation unit.

[0013] Further, the first input end of the ripple voltage effective value loop is connected to the load end ripple voltage set value Urms_set signal end, the second input end is connected to the effective value extraction module output end, and the output end is connected to the first input end of the multiplier;

[0014] The second input terminal of the multiplier is connected to the fixed sine wave signal terminal;

[0015] One input end of the ripple voltage instantaneous value loop is connected to the output end of the multiplier, and the other input end is connected to the output end of the second voltage sampling module.

[0016] Further, the ripple voltage effective value loop includes a first subtractor and a controller G1, the first input end of the first subtractor is connected to the load end ripple voltage set value Urms_set signal end, the second input end is connected to the effective value extraction module output end, the first subtractor output end is connected to the controller G1 input end, and the controller G1 output end is connected to the first input end of the multiplier;

[0017] The ripple voltage instantaneous value loop includes a second subtractor and a controller G2. The first input end of the second subtractor is connected to the output end of the multiplier, the second input end is connected to the output end of the second voltage sampling module, the output end of the second subtractor is connected to the input end of the controller G2, and the controller G2 outputs a sin_pi sinusoidal modulation wave.

[0018] Furthermore, the positive voltage output terminal Udc+ of the high-voltage DC power supply is connected to the secondary side a terminal of the coupling transformer, the secondary side b terminal of the coupling transformer is connected to one end DUT+ of the object under test, the negative voltage output terminal Udc- of the high-voltage DC voltage is connected to the other end of the object under test, and the output terminal of the ripple generator is connected to the primary side of the coupling transformer.

[0019] The advantages of the present invention are as follows: the high-frequency variable load high-voltage direct current ripple power supply control method and system provided by the present invention avoid the technical problems of low ripple amplitude control accuracy, poor system stability, and especially poor load adaptability in conventional technologies, and control the ripple voltage amplitude at the end of the measured object through a ripple voltage effective value loop, and control the frequency and phase of the output voltage of the ripple generator through a ripple voltage instantaneous value loop, thereby achieving amplitude control after the parasitic LC output end and frequency and phase control before the parasitic LC input end, eliminating the influence of the system parasitic LC and greatly improving the load adaptability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The high-frequency variable-load high-voltage DC ripple power supply control system of the present invention;

[0021] Figure 2 Schematic diagram of the effect of parasitic LC on system gain and phase when L=100uH, CDUT=100uF;

[0022] Figure 3 Schematic diagram of the influence of parasitic LC on system gain and phase when L=100uH and CDUT=10uF. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0024] Example 1

[0025] A high-frequency variable load high-voltage direct current ripple power supply control method adopts mixed sampling of a ripple generator output and a measured object end, extracts the effective value of the ripple voltage at the measured object end as feedback of the ripple voltage effective value loop, extracts the voltage waveform of the ripple generator as feedback signal of the ripple voltage instantaneous value loop, thereby forming a ripple voltage effective value loop and a ripple voltage instantaneous value loop, controls the ripple voltage amplitude at the measured object end through the ripple voltage effective value loop, controls the frequency and phase of the ripple generator output voltage through the ripple voltage instantaneous value loop, and outputs a sinusoidal modulation wave sin_pi of the ripple generator.

[0026] Specifically, the calculation method of the sinusoidal modulation wave sin_pi includes the steps of: collecting the voltage at the end of the measured object, extracting the effective value Urms_back through the effective value extraction module (for the sampled digital signal, the calculation formula of the voltage effective value can be expressed as Among them, is the voltage value of the i-th sampling point, n is the number of sampling points), the static error of the load-end ripple voltage set value Urms_set minus Urms_back is adjusted by the G1 controller and multiplied by the sine wave sin2πft, f is the load-end ripple voltage frequency, and the output value minus the static error of the ripple generator output voltage sampling value Uo_back is adjusted by the G2 controller to output the sinusoidal modulation wave sin_pi, and sin_pi controls the ripple generator.

[0027] Coupling transformer leakage inductance Ls, Lw, C DUT The system parasitic LC is formed. After the customer replaces the object under test, the capacitance C of the object under test DUT DUT and the cable equivalent inductance Lw will change unpredictably, resulting in huge changes in the parasitic LC characteristics, such as Figure 2 and Figure 3 As shown in the figure, when the sum of Ls and Lw is L = Ls + Lw = 100uL, the capacitance C of the DUT is DUT The gain and phase difference between 100uF and 10uF is huge, specifically L = 100uH, C DUT =100uF, f=50.7Hz, gain 0.175db, phase angle -0.00789 degrees, f=10kHz, gain -10.4db, phase angle -191 degrees.

[0028] L=100uH,C DUT When =10uF, f=50.3Hz, gain 0.0401db, phase angle 0.000402 degrees, f=10kHz, gain -0.519db, phase angle -156 degrees.

[0029] The capacitance C of the DUT DUTFrom 100uF to 10uF, the gain at 10kHz changes from -10.4db to -0.519db, and the phase angle changes from -191 degrees to -156 degrees. Higher frequencies will produce more unpredictable gain changes and phase shifts; the troubles of parasitic LC on system accuracy and stability cannot be overcome by conventional control methods. The present invention avoids the influence of parasitic LC phase shift on system stability and eliminates the influence of parasitic LC gain on the ripple amplitude at the end of the object being measured.

[0030] The present invention is in the case of L = 100uH, C DUT =10uF, at each frequency, the system setting amplitude U1 and the ripple output amplitude U2 control data of the measured object are as follows:

[0031] Frequency (Hz) 10 100 1k 10k 50k 90k 130k 150k U1(V) 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 U2(V) 20.0 20.0 20.0 20.0 20.1 20.1 20.2 20.1

[0032] Obviously, when the capacitance of the measured object changes, the ripple output amplitude of the control method of the present invention achieves good tracking of the system setting amplitude.

[0033] Example 2

[0034] The method for implementing Example 1 discloses a high-frequency variable load high-voltage DC ripple power supply control system. Please refer to Figure 1 , including a high-voltage DC power supply, a ripple generator, a coupling transformer, a test object and a ripple generator modulation unit, the positive voltage output terminal Udc+ of the high-voltage DC power supply is connected to the secondary side a terminal of the coupling transformer, the secondary side b terminal of the coupling transformer is connected to one end DUT+ of the test object, the negative voltage output terminal Udc- of the high-voltage DC voltage is connected to the other end of the test object, and the output terminal of the ripple generator is connected to the primary side of the coupling transformer.

[0035] The ripple generator modulation unit includes: a first voltage sampling module, a second voltage sampling module, an effective value extraction module, a ripple voltage effective value loop, and a ripple voltage instantaneous value loop. The input end of the first voltage sampling module is connected to the ripple voltage at the end of the measured object, the output end of the first voltage sampling module is connected to the input end of the effective value extraction module, the output end of the effective value extraction module is connected to the input end of the ripple generator modulation unit, the input end of the second voltage sampling module is connected to the output end of the ripple generator, and the output end of the second voltage sampling module is connected to the other input end of the ripple generator modulation unit.

[0036] The first input end of the ripple voltage effective value loop is connected to the load end ripple voltage set value Urms_set signal end, the second input end is connected to the effective value extraction module output end, and the output end is connected to the first input end of the multiplier; the second input end of the multiplier is connected to the fixed sine wave signal end; one input end of the ripple voltage instantaneous value loop is connected to the output end of the multiplier, and the other input end is connected to the output end of the second voltage sampling module.

[0037] The ripple voltage effective value loop includes a first subtractor and a controller G1, the first input end of the first subtractor is connected to the load end ripple voltage set value Urms_set signal end, the second input end is connected to the effective value extraction module output end, the first subtractor output end is connected to the controller G1 input end, and the controller G1 output end is connected to the first input end of the multiplier; the ripple voltage instantaneous value loop includes a second subtractor and a controller G2, the first input end of the second subtractor is connected to the multiplier output end, the second input end is connected to the second voltage sampling module output end, the second subtractor output end is connected to the controller G2 input end, and the controller G2 outputs a sin_pi sinusoidal modulation wave.

[0038] Controllers G1 and G2 are both proportional controllers (set value minus feedback value multiplied by proportional gain) or proportional-integral controllers (set value minus feedback value multiplied by proportional gain and integrated).

[0039] Finally, it should be noted that the above 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 in the protection scope of the present invention.

Claims

1. A high-frequency variable load high-voltage DC ripple power supply control method, characterized in that: The ripple generator output and the measured object end are mixedly sampled, the ripple voltage effective value at the measured object end is extracted as the feedback of the ripple voltage effective value loop, and the voltage waveform of the ripple generator is extracted as the feedback signal of the ripple voltage instantaneous value loop, thereby forming a ripple voltage effective value loop and a ripple voltage instantaneous value loop. The ripple voltage amplitude at the measured object end is controlled by the ripple voltage effective value loop, and the ripple voltage instantaneous value loop controls the frequency and phase of the ripple generator output voltage, and outputs the sinusoidal modulation wave sin_pi of the ripple generator.

2. The high-frequency variable load high-voltage DC ripple power supply control method according to claim 1, characterized in that: The calculation method of the sinusoidal modulated wave sin_pi includes the steps of collecting the voltage at the end of the measured object, extracting the effective value Urms_back through the effective value extraction module, multiplying the static error of the load end ripple voltage set value Urms_set minus Urms_back with a set sine wave after adjustment by the G1 controller, and outputting the sinusoidal modulated wave sin_pi after the static error of the output voltage sampling value Uo_back of the ripple generator is subtracted from the output value obtained by adjustment by the G2 controller.

3. The high-frequency variable load high-voltage DC ripple power supply control method according to claim 2, characterized in that: The set sine wave is sin2πft, and f is the load end ripple voltage frequency.

4. A high-frequency variable load high-voltage DC ripple power supply control system, comprising a high-voltage DC power supply, a ripple generator, a coupling transformer, a measured object and a ripple generator modulation unit, characterized in that: The ripple generator modulation unit comprises: A first voltage sampling module, a second voltage sampling module, an effective value extraction module, a ripple voltage effective value loop, and a ripple voltage instantaneous value loop, wherein the input end of the first voltage sampling module is connected to the ripple voltage at the end of the measured object, the output end of the first voltage sampling module is connected to the input end of the effective value extraction module, the output end of the effective value extraction module is connected to the input end of the ripple generator modulation unit, the input end of the second voltage sampling module is connected to the output end of the ripple generator, and the output end of the second voltage sampling module is connected to the other input end of the ripple generator modulation unit.

5. The high-frequency variable load high-voltage DC ripple power supply control system according to claim 4, characterized in that: The first input end of the ripple voltage effective value loop is connected to the load end ripple voltage set value Urms_set signal end, the second input end is connected to the effective value extraction module output end, and the output end is connected to the first input end of the multiplier; The second input terminal of the multiplier is connected to the fixed sine wave signal terminal; One input end of the ripple voltage instantaneous value loop is connected to the output end of the multiplier, and the other input end is connected to the output end of the second voltage sampling module.

6. The high-frequency variable load high-voltage DC ripple power supply control system according to claim 5, characterized in that: The ripple voltage effective value loop includes a first subtractor and a controller G1, wherein the first input end of the first subtractor is connected to the load end ripple voltage set value Urms_set signal end, the second input end is connected to the effective value extraction module output end, the first subtractor output end is connected to the controller G1 input end, and the controller G1 output end is connected to the first input end of the multiplier; The ripple voltage instantaneous value loop includes a second subtractor and a controller G2, the first input end of the second subtractor is connected to the output end of the multiplier, the second input end is connected to the output end of the second voltage sampling module, the output end of the second subtractor is connected to the input end of the controller G2, and the controller G2 outputs a sin_pi sinusoidal modulation wave.

7. The high-frequency variable load high-voltage DC ripple power supply control system according to claim 4, characterized in that: The positive voltage output terminal Udc+ of the high-voltage direct current power supply is connected to the secondary side a terminal of the coupling transformer, the secondary side b terminal of the coupling transformer is connected to one end of the object under test DUT+, the negative voltage output terminal Udc- of the high-voltage direct current voltage is connected to the other end of the object under test, and the output terminal of the ripple generator is connected to the primary side of the coupling transformer.

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