A high-harmonic high-efficiency AC power supply and control method thereof

Abstract

Limited by the switching frequency of the switching device, the circuit of the traditional technology can no longer achieve harmonics and interharmonics in a higher frequency range. The present invention belongs to the field of electronic technology, and proposes a high-harmonic high-efficiency AC power supply and a control method thereof. The equivalent amplification factor is configured with a suitable loss coefficient k, which can achieve a reasonable and controlled linear tube voltage drop, and finally achieve a reasonable and controllable linear tube loss, thereby reducing the linear tube loss.

Description

Technical Field

[0001] The invention relates to the technical field of power electronics, and in particular to a high-harmonic high-efficiency AC power supply and a control method thereof. Background Art

[0002] In the power system, in addition to the fundamental wave (i.e. the same wave as the power frequency), there may be other frequency waves, which are called harmonics. Higher harmonics usually refer to harmonics with frequencies higher than the fundamental frequency. These harmonics may cause power loss, equipment overheating, electromagnetic interference and other problems.

[0003] The generation and testing of high-order harmonics place extremely high demands on power supply circuits. Traditional AC power supply circuit topologies often have limitations in design and implementation, and it is difficult to support the generation of harmonics in a higher frequency range. Due to the performance limitations of key components such as switching devices and filters in the circuit, it is difficult for the circuit to maintain a stable and efficient working state at high frequencies. Currently, most devices with this function can achieve a maximum harmonic order range of 2-50. Secondly, the problem of low interharmonic synthesis bandwidth frequency cannot be ignored. Interharmonics are complex waveforms generated by the interaction between harmonics, and their synthesis and testing require high-precision signal processing and control technology. However, current technical means often face problems such as signal distortion and noise interference when processing high-frequency and high-complexity interharmonic signals, resulting in the limitation of the synthesis bandwidth frequency. Now, 3000Hz is basically the maximum interharmonic bandwidth that can be achieved at the maximum switching frequency that mainstream switching devices can withstand.

[0004] It can be seen that due to the switching frequency limitation of the switching device, the circuit of traditional technology can no longer achieve harmonics and interharmonics in a higher frequency range. Summary of the invention

[0005] The purpose of the present invention is to provide a high-harmonic high-efficiency AC power supply and a control method thereof, which can not only meet the requirements of high-harmonic testing with a higher frequency range and more complex waveforms, but also optimize equipment performance and reduce losses.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] A high-harmonic high-efficiency AC power supply, comprising an AC power supply circuit, a switch part control circuit, and a linear part control circuit;

[0008] The AC power supply circuit includes: the negative electrode of the bus power supply V1 is connected to the positive electrode of the bus power supply V2, the connection point of the bus power supplies V1 and V2 is COM, the first end of the switch tube T1 is connected to the positive electrode of V1, the second end of T1 is connected to the first end of the switch tube T2, the second end of T2 is connected to the negative electrode of V2, the connection point of the switch tubes T1 and T2 is A, the connection point A is connected to the first end of the filter inductor L, the second end of the filter inductor L is respectively connected to the positive electrode of the diode D3 and the negative electrode of the diode D4, the negative electrode of D3 is connected to the first end of the capacitor C1, the second end of the capacitor C1 and the first end of C2 are connected to the point COM, the positive electrode of D4 is connected to the second end of the capacitor C2, the first end of the linear tube Q1 is connected to the first end of C1, the second end of the linear tube Q2 is connected to the second end of C2, the second end of Q1 and the first end of Q2 are connected to point S and grounded, and a load resistor RL is connected between the connection point S and the connection point COM;

[0009] The switch part control circuit includes a proportional integral circuit formed by an operational amplifier U2 and a carrier modulation part. The output of the operational amplifier U2 is connected to the input of the carrier modulation part, and after modulation, the drive signals S1 and S2 are output. S1 is used to drive the switch tube T1, and S2 is used to drive the switch tube T2.

[0010] The linear part control circuit includes a proportional integral circuit formed by an operational amplifier U1, and the output of the operational amplifier U1 is connected to the gates G of the linear tubes Q1 and Q2.

[0011] Furthermore, the linear part control circuit includes: an operational amplifier U1, resistors R1, R2, R3, and a capacitor C3. The non-inverting input terminal of the operational amplifier U1 is connected to the resistor R1, and the inverting input terminal is connected to the resistor R2. A resistor R3 and a capacitor C3 connected in series are connected between the output terminal and the inverting input terminal. The output terminal, as the output terminal of the linear part control circuit, is connected to the gates G of the linear tubes Q1 and Q2.

[0012] A high-harmonic high-efficiency AC power supply control method is based on the above-mentioned high-harmonic high-efficiency AC power supply, which is divided into a positive half-cycle and a negative half-cycle;

[0013] In the positive half cycle, when the modulation wave Uv_REF is greater than the positive carrier uc1, T1 is turned on, the UA-COM voltage value is V1, and the inductor is charged; when the modulation wave Uv_REF is less than the positive carrier uc1, T1 is turned off, the UA-COM voltage value is -V2, the inductor continues to flow, and D3 is selected in the positive half cycle. After filtering by the filter inductor L and the capacitor C1, the voltage across C1 is a sinusoidal positive half-wave VC1, A is the connection point of the switch tubes T1 and T2, COM is the connection point of the bus power supply V1 and V2, and the UA-COM voltage is the voltage between the connection point A and the connection point COM;

[0014] In the negative half cycle, when the modulation wave Uv_REF is less than the load wave uc2, T2 is turned on, the UA-COM voltage value is -V2, and the inductor is charged; when the modulation wave Uv_REF is greater than the load wave uc2, T2 is turned off, the UA-COM voltage value is V1, the inductor continues to flow, and D4 is selected in the negative half cycle. After filtering by the filter inductor L and the capacitor C2, the voltage across C2 is the sinusoidal negative half wave VC2.

[0015] Furthermore, V1=V2. During the entire cycle, the voltage from the upper end of capacitor C1 to the lower end of capacitor C2 is a full-cycle sinusoidal voltage Uv. Uv is in phase with the modulation wave Uv_REF, and the amplitude is controlled by Uv_REF.

[0016] Furthermore, the input signal of the inverting input terminal of the operational amplifier U2 in the switch part control circuit is the sampling value Uv_back of Uv, Uv is the positive periodic sinusoidal voltage from the upper end of the capacitor C1 to the lower end of the capacitor C2, and the input signal of the non-inverting input terminal is the given value Uv_REF. The input signal of the inverting input terminal of the operational amplifier U1 in the linear part control circuit is the sampling value of the output voltage Uo across the load resistor RL, and the input signal of the non-inverting input terminal is the given value Uo_REF.

[0017] Furthermore, the reference value Uo_REF of Uo is:

[0018]

[0019] Wherein, A1 is the peak value of the fundamental voltage, Ai is the peak value of the i-th harmonic, w is the fundamental frequency, t is the time, i≥2 and i is a positive integer; Bi is the harmonic order, which can be an integer or a fraction. When Bi is an integer, the harmonic is an odd harmonic or an even harmonic. When Bi is a fraction, the harmonic is an interharmonic.

[0020] Furthermore, according to the given value Uo_REF, Uv_REF is obtained after amplitude transformation and fundamental wave extraction:

[0021]

[0022] Finally, we get:

[0023]

[0024] in , i is the harmonic order, k is the loss coefficient and k>1;

[0025] The linear tube pressure drop is:

[0026]

[0027] Wherein, M is the equivalent amplification factor of the circuit from the given signal to the output voltage Uo.

[0028] The advantages of the present invention are as follows: for a certain specific system, in actual engineering, through a simple debugging process, the equivalent amplification factor is configured with a suitable loss coefficient k, so that the linear tube voltage drop can be reasonable and controlled, and finally the linear tube loss can be reasonably controlled, the linear tube loss is reduced, and at the same time, the AC output high-order harmonic synthesis and high-order interharmonic synthesis are realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a circuit diagram of the present invention;

[0030] Figure 2 It is a schematic diagram of the modulation method of the present invention;

[0031] Figure 3 It is the waveform diagram of the relationship between Uv_REF and Uo_REF of the present invention;

[0032] Figure 4 This is a processing flow chart from Uo_REFd to Uv_REF of the present invention. DETAILED DESCRIPTION

[0033] 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.

[0034] Example 1

[0035] This embodiment discloses a high-harmonic high-efficiency AC power supply. Please refer to Figure 1 , including an AC power supply circuit, a switch part control circuit, and a linear part control circuit.

[0036] The AC power supply circuit includes: the negative electrode of the bus power supply V1 is connected to the positive electrode of the bus power supply V2, the connection point of the bus power supplies V1 and V2 is COM, the first end of the switch tube T1 is connected to the positive electrode of V1, the second end of T1 is connected to the first end of the switch tube T2, the second end of T2 is connected to the negative electrode of V2, the connection point of the switch tubes T1 and T2 is A, the connection point A is connected to the first end of the filter inductor L, the second end of the filter inductor L is respectively connected to the positive electrode of the diode D3 and the negative electrode of the diode D4, the negative electrode of D3 is connected to the first end of the capacitor C1, the second end of the capacitor C1 and the first end of C2 are connected to point COM, the positive electrode of D4 is connected to the second end of the capacitor C2, the first end of the linear tube Q1 is connected to the first end of C1, the second end of the linear tube Q2 is connected to the second end of C2, the second end of Q1 and the first end of Q2 are connected to point S and grounded, and a load resistor RL is connected between the connection point S and the connection point COM.

[0037] The switch part control circuit includes a proportional integration circuit formed by an operational amplifier U2 and a carrier modulation part. The output of the operational amplifier U2 is connected to the input of the carrier modulation part, and after modulation, the drive signals S1 and S2 are output. S1 is used to drive the switch tube T1, and S2 is used to drive the switch tube T2. The in-phase input end of U2 is connected to a resistor R21, the inverting input end is connected to a resistor R22, and a resistor R23 and a capacitor C23 connected in series are connected between the output end and the inverting input end to form a proportional integrator. The output end of U2 is connected to the carrier modulation part, and is used to output the drive signal S1 of the switch tube T1 and the drive signal S2 of the switch tube T2.

[0038] The linear part control circuit includes: an operational amplifier U1, resistors R1, R2, R3, and a capacitor C3. The non-inverting input terminal of the operational amplifier U1 is connected to the resistor R1, the inverting input terminal is connected to the resistor R2, and the resistor R3 and the capacitor C3 are connected in series between the output terminal and the inverting input terminal to form a proportional integrator. The output terminal of U1 is connected to the gate G of the linear tubes Q1 and Q2 as the output terminal of the linear part control circuit.

[0039] Example 2

[0040] This embodiment discloses a high-harmonic high-efficiency AC power supply control method, please refer to Figure 2 , based on the power supply circuit of Example 1.

[0041] In the positive half cycle, when the modulation wave Uv_REF is greater than the positive carrier uc1, T1 is turned on, the UA-COM voltage value is V1, and the inductor is charged; when the modulation wave Uv_REF is less than the positive carrier uc1, T1 is turned off, the UA-COM voltage value is -V2, the inductor continues to flow, and D3 is selected in the positive half cycle. After filtering by the filter inductor L and the capacitor C1, the voltage across C1 is a sinusoidal positive half-wave VC1, A is the connection point of the switch tubes T1 and T2, COM is the connection point of the bus power supply V1 and V2, and the UA-COM voltage is the voltage between the connection point A and the connection point COM;

[0042] In the negative half cycle, when the modulation wave Uv_REF is less than the load wave uc2, T2 is turned on, the UA-COM voltage value is -V2, and the inductor is charged; when the modulation wave Uv_REF is greater than the load wave uc2, T2 is turned off, the UA-COM voltage value is V1, the inductor continues to flow, and D4 is selected in the negative half cycle. After filtering by the filter inductor L and the capacitor C2, the voltage across C2 is the sinusoidal negative half wave VC2.

[0043] V1=V2. During the entire cycle, the voltage from the upper end of capacitor C1 to the lower end of capacitor C2 is a full-cycle sinusoidal voltage Uv. Uv is in phase with the modulation wave Uv_REF, and its amplitude is controlled by Uv_REF.

[0044] The input signal of the inverting input terminal of the operational amplifier U2 in the switch part control circuit is the sampling value Uv_back of Uv, Uv is the positive period sinusoidal voltage from the upper end of the capacitor C1 to the lower end of the capacitor C2, and the input signal of the non-inverting input terminal is the given value Uv_REF. The input signal of the inverting input terminal of the operational amplifier U1 in the linear part control circuit is the sampling value of the output voltage Uo across the load resistor RL, please refer to 3, and the input signal of the non-inverting input terminal is the given value Uo_REF.

[0045] First set the reference value Uo_REF of the output voltage Uo:

[0046]

[0047] Wherein, A1 is the peak value of the fundamental voltage, Ai is the peak value of the i-th harmonic, w is the fundamental frequency, t is the time, i≥2 and i is a positive integer; Bi is the harmonic order, which can be an integer or a fraction. When Bi is an integer, the harmonic is an odd harmonic or an even harmonic. When Bi is a fraction, the harmonic is an interharmonic.

[0048] Then, the given value Uv_REF of the voltage Uv from the upper end of capacitor C1 to the lower end of capacitor C2 is determined according to the given value Uo_REF of Uo. The control process is as follows: Figure 4 , Uo_REF is converted into Uv_REF after amplitude conversion and fundamental wave extraction. The specific calculation is: amplitude conversion and fundamental wave extraction:

[0049]

[0050] Finally, we get Uv_REF:

[0051]

[0052] in , i is the harmonic order, k is the loss coefficient and k>1, the larger k is, the greater the linear tube loss is.

[0053] The above control result is that the linear tube pressure drop UQ=UQ1+UQ2, UQ1 is the Q1 tube pressure drop, UQ2 is the Q2 tube pressure drop, and the waveform is as follows: Figure 3 , the linear tube pressure drop is:

[0054]

[0055] Among them, M is the equivalent amplification factor of the circuit from the given signal to the output voltage Uo. For a specific system, M is certain and fixed. In actual engineering, through a simple debugging process, the appropriate loss coefficient k is configured to achieve a reasonable and controlled linear tube voltage drop, and finally achieve a reasonable and controllable linear tube loss.

[0056] 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-harmonic high-efficiency AC power supply, characterized in that: It includes an AC power supply circuit, a switch part control circuit, and a linear part control circuit; The AC power supply circuit includes: a negative electrode of a bus power supply V1 is connected to a positive electrode of a bus power supply V2, a connection point between bus power supplies V1 and V2 is COM, a first end of a switch tube T1 is connected to a positive electrode of V1, a second end of T1 is connected to a first end of a switch tube T2, a second end of T2 is connected to a negative electrode of V2, a connection point between switch tubes T1 and T2 is A, connection point A is connected to a first end of a filter inductor L, a second end of the filter inductor L is respectively connected to a positive electrode of a diode D3 and a negative electrode of a diode D4, a negative electrode of D3 is connected to a first end of a capacitor C1, a second end of the capacitor C1 is connected to a first end of C2 at point COM, a positive electrode of D4 is connected to a second end of the capacitor C2, a first end of a linear tube Q1 is connected to a first end of C1, a second end of the linear tube Q2 is connected to a second end of C2, a second end of Q1 is connected to a first end of Q2 at point S and grounded, and a load resistor RL is connected between the connection point S and the connection point COM; The switch part control circuit includes a proportional integral circuit formed by an operational amplifier U2 and a carrier modulation part. The output of the operational amplifier U2 is connected to the input of the carrier modulation part, and the drive signals S1 and S2 are output after modulation. S1 is used to drive the switch tube T1, and S2 is used to drive the switch tube T2. The linear part control circuit includes a proportional integral circuit formed by an operational amplifier U1, and the output of the operational amplifier U1 is connected to the gates G of the linear tubes Q1 and Q2.

2. The high-harmonic high-efficiency AC power supply according to claim 1, characterized in that: The linear part control circuit includes: an operational amplifier U1, resistors R1, R2, R3, and a capacitor C3. The non-inverting input terminal of the operational amplifier U1 is connected to the resistor R1, and the inverting input terminal is connected to the resistor R2. A resistor R3 and a capacitor C3 connected in series are connected between the output terminal and the inverting input terminal. The output terminal, as the output terminal of the linear part control circuit, is connected to the gates G of the linear tubes Q1 and Q2.

3. A high-harmonic high-efficiency AC power supply control method, based on the high-harmonic high-efficiency AC power supply according to claim 1 or 2, characterized in that: It is divided into positive half cycle and negative half cycle; In the positive half cycle, when the modulation wave Uv_REF is greater than the positive carrier uc1, T1 is turned on, the UA-COM voltage value is V1, and the inductor is charged; when the modulation wave Uv_REF is less than the positive carrier uc1, T1 is turned off, the UA-COM voltage value is -V2, the inductor continues to flow, and D3 is selected in the positive half cycle. After filtering by the filter inductor L and the capacitor C1, the voltage across C1 is a sinusoidal positive half-wave VC1, A is the connection point of the switch tubes T1 and T2, COM is the connection point of the bus power supply V1 and V2, and the UA-COM voltage is the voltage between the connection point A and the connection point COM; In the negative half cycle, when the modulation wave Uv_REF is less than the load wave uc2, T2 is turned on, the UA-COM voltage value is -V2, and the inductor is charged; when the modulation wave Uv_REF is greater than the load wave uc2, T2 is turned off, the UA-COM voltage value is V1, the inductor continues to flow, and D4 is selected in the negative half cycle. After filtering by the filter inductor L and the capacitor C2, the voltage across C2 is the sinusoidal negative half wave VC2.

4. The high-harmonic high-efficiency AC power modulation method according to claim 3, characterized in that: V1=V2. During the entire cycle, the voltage from the upper end of capacitor C1 to the lower end of capacitor C2 is a full-cycle sinusoidal voltage Uv. Uv is in phase with the modulation wave Uv_REF, and its amplitude is controlled by Uv_REF.

5. The high-harmonic high-efficiency AC power modulation method according to claim 3, characterized in that: The input signal of the inverting input terminal of the operational amplifier U2 in the switch part control circuit is the sampling value Uv_back of Uv, Uv is the positive periodic sinusoidal voltage from the upper end of the capacitor C1 to the lower end of the capacitor C2, and the input signal of the non-inverting input terminal is the given value Uv_REF. The input signal of the inverting input terminal of the operational amplifier U1 in the linear part control circuit is the sampling value of the output voltage Uo across the load resistor RL, and the input signal of the non-inverting input terminal is the given value Uo_REF.

6. The high-harmonic high-efficiency AC power modulation method according to claim 5, characterized in that: The reference value of Uo Uo_REF is: Wherein, A1 is the peak value of the fundamental voltage, Ai is the peak value of the i-th harmonic, w is the fundamental frequency, t is the time, i≥2 and i is a positive integer; Bi is the harmonic order, which can be an integer or a fraction. When Bi is an integer, the harmonic is an odd harmonic or an even harmonic. When Bi is a fraction, the harmonic is an interharmonic.

7. The high-harmonic high-efficiency AC power modulation method according to claim 6, characterized in that: According to the given value Uo_REF, Uv_REF is obtained after amplitude transformation and fundamental wave extraction: Finally, we get: in , i is the harmonic order, k is the loss coefficient and k>1; The linear tube pressure drop is: Wherein, M is the equivalent amplification factor of the circuit from the given signal to the output voltage Uo.

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