Method for suppressing input three-phase harmonic current of ship power supply equipment

Abstract

The invention discloses a method for suppressing input three-phase harmonic current of ship power supply equipment, which comprises the following steps of: firstly, determining the times and loop parameters of specific harmonic current needing to be compensated by a PFC (Power Factor Correction) unit of the power supply equipment under the working condition by combining a CE101 test chart and the size of an array load, so that harmonic current control participates in the existing PFC current loop control; therefore, the content of the input harmonic current is adjusted to be lower than the CE101 limit value. On the basis of a PFC digital control unit of original equipment, a control method for suppressing input of three-phase harmonic current is added, and an electric reactor or an active power filter (APF) device is omitted, so that the problem that part of sub-harmonic current exceeds a CE101 limit value is solved.

Description

Technical Field

[0001] The invention belongs to the field of automatic control systems, and in particular relates to a method for suppressing three-phase harmonic current input to ship power equipment. Background Art

[0002] Since the application of three-phase power factor corrector (PFC) power supply, it has been widely used in three-phase input current harmonic suppression. The existing three-phase PFC digital power supply often only controls the fundamental current. In order to reduce the volume of the power supply, the input inductance is designed according to the full load. Usually, when the power supply equipment is more than half-loaded, it can meet the requirements of the ship CE101 project in GJB151B. However, the actual power supply equipment needs to supply power to different load types. When it is used in the array load occasion, because the array has the characteristics of full-range load, when the CE101 project is tested in the light load working mode, due to the low input inductance, the PFC part cannot effectively suppress the input current harmonics, and some subharmonic currents exceed the standard, which limits its application. When the power supply equipment is not equipped with an active power filter (APF) and the state is solidified, it is not allowed to connect a large reactor in series on the input line to solve this problem. Summary of the invention

[0003] The present invention proposes a method for suppressing three-phase harmonic current input to ship power supply equipment, a method for suppressing three-phase harmonic current input to ship power supply equipment, a harmonic compensation control is added to the original power supply equipment PFC part current digital control unit to solve the problem of excessive harmonics in some CE101, and the method is used in three-phase rectifier power supply, PFC power supply and other occasions.

[0004] The technical solution to achieve the purpose of the present invention is: a method for suppressing three-phase harmonic current input to ship power supply equipment, the specific steps are:

[0005] Step 1, perform CE101 test on the three-phase input power under the surface load condition to obtain the CE101 test diagram;

[0006] Step 2: According to the CE101 test diagram, determine whether specific harmonic compensation setting is required. If not, the three-phase power is subjected to fundamental current PI loop control and then output to the main power circuit unit of the PFC power supply; otherwise, the fundamental current PI loop control and specific harmonic compensation control are performed and then output to the main power circuit unit of the PFC power supply.

[0007] Preferably, according to the CE101 test diagram, the specific method for determining whether specific harmonic compensation adjustment is required is:

[0008] Firstly, analyze the harmonic content of the CE101 test chart to obtain the frequency value and amplitude of the exceeding point;

[0009] When the three-phase current is greater than 1 / 2 of the full-load current and the CE101 over-limit value does not exceed the set threshold, no specific harmonic compensation setting is required;

[0010] When the three-phase current does not exceed 1 / 2 of the full load current, specific subharmonic compensation setting is required.

[0011] Preferably, the specific process of performing fundamental current PI loop control on three-phase electricity is:

[0012] The three-phase current is transformed by abc / dq to obtain the d-axis component current and q-axis component current in the dq coordinate system. The DC voltage loop output reference is subtracted from the d-axis component current to obtain the error. The error is subjected to fundamental PI control to obtain the controlled output current. The controlled output current is added with the voltage feedforward component to obtain the d-axis component after fundamental PI control. The q-axis component current is adjusted according to the reactive power being 0, and the controlled output current is obtained through fundamental PI control, and the voltage feedforward component V is added. q =0 to obtain the q-axis component after fundamental wave PI control, and the d-axis component and q-axis component after fundamental wave PI control are subjected to dq / abc inverse transformation and SPWM modulation and then output to the main power circuit unit of the PFC power supply.

[0013] Preferably, the specific method for performing fundamental current PI loop control and specific subharmonic compensation control is:

[0014] The three-phase current is transformed by abc / dq to obtain the dq current in the dq coordinate system, and the dq current is respectively subjected to fundamental current PI control while performing specific harmonic compensation control, and the dq current output by the fundamental current PI control and the dq current output by the specific harmonic compensation control are added together, and then a voltage feedforward component is added, and the dq current with the voltage feedforward component is subjected to dq / abc inverse transformation and SPWM modulation, and then output to the main power circuit unit of the PFC power supply.

[0015] Preferably, the complete process of performing fundamental current PI loop control and specific subharmonic compensation control is:

[0016] Perform abc / dq transformation on the three-phase current to obtain the d-axis component current i in the dq coordinate system d and the q-axis component current i q , DC voltage loop output reference i dref Subtract the d-axis component current i d Get the error amount i d_err , error amount i d_err Perform fundamental wave PI control to obtain i d1_out , while the error i d_err After the 6th / 12th / 18th / 24th / 30th harmonic compensation control, the specific harmonic controller output i is obtained by addingd_nthout , the specific subharmonic controller output i d_nthout The i obtained by fundamental wave PI control d1_out Added as the d-axis current loop control output i dout , plus the voltage feedforward component V d , sent to the dq / abc inverse transformation; q-axis component current i q According to the reactive power being 0, the fundamental wave PI is used to adjust i q1_out , obtained by a specific subharmonic compensation controller q_nthout ,i q_nthout with i q1_out The sum is the q-axis current loop control output i qout , plus the voltage feedforward component V q =0, and sent to dq / abc inverse conversion; the current after dq / abc inverse conversion is modulated by PWM and sent to the main power circuit unit of the PFC power supply.

[0017] Preferably, a second-order resonant controller is used to perform specific harmonic compensation control, and the 3rd to 9th harmonics are suppressed by the 6th harmonic compensation, the 9th to 15th harmonics are suppressed by the 12th harmonic compensation, the 15th to 21st harmonics are suppressed by the 18th harmonic compensation, the 21st to 27th harmonics are suppressed by the 24th harmonic compensation, and the 27th to 33rd harmonics are suppressed by the 30th harmonic compensation.

[0018] Compared with the prior art, the present invention has the following significant advantages: in combination with the actual rectification needs of the current ship power supply equipment for exceeding the electromagnetic compatibility CE101 project, on the basis of the existing PFC loop control of the power supply equipment, the present invention proposes that the current loop adopts a specific sub-harmonic compensation control method to achieve the suppression of some sub-harmonic currents and achieve a limit below CE101. The control method is easy to implement and can be used in the existing power supply control, and has the advantages of simple algorithm and good adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The figure is an overall block diagram of the input three-phase harmonic current suppression method described in the present invention.

[0020] Figure 2 This is a flow chart of the current loop control described in the present invention.

[0021] Figure 3 This is the existing traditional current loop control flow chart.

[0022] Figure 4 This is the digital discretization control diagram of the sixth harmonic compensation control described in the present invention.

[0023] Figure 5This is the test diagram of the A-phase current CE101 of the power supply equipment described in the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings.

[0025] like Figure 1 to Figure 5 As shown, a method for suppressing three-phase harmonic current input to a ship power supply device comprises:

[0026] Step 1: Perform CE101 test on the three-phase input power under the surface load condition to obtain the CE101 test diagram;

[0027] Step 2: According to the CE101 test diagram, determine whether specific harmonic compensation setting is required. If not, the three-phase power is subjected to fundamental current PI loop control and then output to the main power circuit unit of the PFC power supply; otherwise, the fundamental current PI loop control and specific harmonic compensation control are performed and then output to the main power circuit unit of the PFC power supply.

[0028] In a further embodiment, in combination Figure 1 The obtained CE101 test graph is first analyzed for harmonic content to obtain the frequency value (Hz) and amplitude value (dB) of the exceeding point, and then the harmonic compensation is determined. a ,i b ,i c ) is greater than 1 / 2 full load current and the CE101 over-limit value does not exceed 2dB, perform step 3 conventional current loop control; when the three-phase current (i a ,i b ,i c ) does not exceed 1 / 2 of the full load current, and perform current loop control under harmonic compensation according to step 4.

[0029] In a further embodiment, when harmonic compensation is not required, Figure 2 In the current loop control (202), the two switches are switched to a, that is, the harmonic compensation sub-function is skipped in the program. Figure 3 The existing traditional current loop control is carried out as follows:

[0030] The three-phase current is transformed by abc / dq to obtain the d-axis component current and q-axis component current in the dq coordinate system. The DC voltage loop output reference is subtracted from the d-axis component current to obtain the error. The error is subjected to fundamental PI control to obtain the controlled output current. The controlled output current is added with the voltage feedforward component to obtain the d-axis component after fundamental PI control. The q-axis component current is adjusted according to the reactive power being 0, and the controlled output current is obtained through fundamental PI control, and the voltage feedforward component V is added. q=0 to obtain the q-axis component after fundamental wave PI control, and the d-axis component and q-axis component after fundamental wave PI control are subjected to dq / abc inverse transformation and SPWM modulation and then output to the main power circuit unit of the PFC power supply.

[0031] The three-phase PFC power supply performs fundamental current PI loop control in the dq coordinate system. By adjusting the PI parameters and changing the loop bandwidth, the overall suppression of input current harmonics is achieved, so that the amplitude of the exceeding point is less than the limit specified by CE101. This is only applicable when the amplitude of the exceeding point does not exceed 2dB. When the exceeding point is higher than 2dB, excessive adjustment of the PI parameters may cause oscillation of the power supply control loop. At this time, the three-phase input filter inductor needs to be redesigned to meet the CE101 requirements.

[0032] In a further embodiment, when harmonic compensation is required, Figure 2 The two switches in the current loop control (202) are switched to b, that is, the harmonic compensation sub-function is enabled in the program. Figure 3 In the 50Hz fundamental PI control, a specific harmonic compensation control composed of a second-order resonator is incorporated, and the resonant frequency is the 6th / 12th / 18th / 24th / 30th fundamental. The effective range of harmonic compensation control is up to the frequency of 1.65kHz (33rd harmonic), and the maximum amplitude suppression range does not exceed 10dB. Because the harmonic compensation part has no obvious effect on the harmonic suppression of the edge exceeding the standard point frequency less than 250Hz or higher than 1.6kHz, when the exceeding amplitude is still less than 2dB, combined with step 2, the fundamental PI parameters are adjusted synchronously. The complete scheme of current loop control under harmonic compensation is as follows:

[0033] DC voltage loop output reference i dref Subtract the input current i a ,i b ,i c i after abc / dq transformation d The error i d_err , where abc / dq conversion requires the output phase-locked angle θ of the three-phase input voltage phase-locked loop, and the error i d_err Perform fundamental wave PI control to obtain i d1_out , while the error i d_err The sum of the 6th / 12th / 18th / 24th / 30th harmonic compensation control is sent to the b-end of the switch (that is, harmonic compensation is enabled), where the specific harmonic controller is a typical second-order resonant controller, as shown in the following example: Figure 4As shown, it has a bandpass filter characteristic. To avoid oscillation in the current control loop, the 6th harmonic compensation is used to suppress the 3rd to 9th harmonics, the 12th harmonic compensation is used to suppress the 9th to 15th harmonics, the 18th harmonic compensation is used to suppress the 15th to 21st harmonics, the 24th harmonic compensation is used to suppress the 21st to 27th harmonics, and the 30th harmonic compensation is used to suppress the 27th to 33rd harmonics. The i of the specific harmonic controller output is d_nthout with i d1_out The sum is the d-axis current loop control output i dout , plus the voltage feedforward component V d , sent to the dq / abc inverse transformation; input current i a ,i b ,i c i after abc / dq transformation d The components are adjusted according to the reactive power being 0, and the fundamental wave PI is adjusted to obtain i q1_out , obtained by a specific subharmonic compensation controller q_nthout ,i q_nthout with i q1_out The sum is the q-axis current loop control output i qout , plus the voltage feedforward component V q =0, sent to the dq / abc inverse conversion, and finally sent to the main power circuit unit of the PFC power supply through PWM modulation.

[0034] Figure 4 The digital discretization control diagram for the sixth harmonic compensation control is shown in Figure 1. The resonant frequency is 300 Hz. The second-order resonant controller is transformed by differential transformation to obtain the Z-domain discretization control diagram. The input error i d_err Classic d_err1 、i d_err2 Get i d_6thout , the parameter variable involved is K 1 , K 2 , K 3 The specific value is determined by the actual test diagram and suppression effect. The control block diagram of other harmonic compensation is the same as the 6th.

[0035] Figure 5 When the power supply equipment is loaded with array, the input current is less than 1 / 2 of the full load CE101 test diagram of the A-phase current. The figure shows that the 350Hz (7th harmonic) point exceeds the standard by about 1.5dB, and the 650Hz (13th harmonic) point exceeds the standard by about 8dB. According to the above steps, the 6th and 12th specific harmonic compensation controls need to be incorporated into the current loop control to suppress the 7th and 13th harmonic currents that exceed the standard point to meet the test CE101 requirements.

Claims

1. A method for suppressing three-phase harmonic current input to a ship power supply device, characterized in that: The specific steps are: Step 1, perform CE101 test on the three-phase input power under the surface load condition to obtain the CE101 test diagram; Step 2: According to the CE101 test diagram, determine whether specific harmonic compensation setting is required. If not, the three-phase power is subjected to fundamental current PI loop control and then output to the main power circuit unit of the PFC power supply; otherwise, the fundamental current PI loop control and specific harmonic compensation control are performed and then output to the main power circuit unit of the PFC power supply.

2. The method for suppressing three-phase harmonic current input to ship power supply equipment according to claim 1 is characterized in that: According to the CE101 test diagram, the specific method to determine whether specific harmonic compensation adjustment is required is as follows: Firstly, analyze the harmonic content of the CE101 test chart to obtain the frequency value and amplitude of the exceeding point; When the three-phase current is greater than 1 / 2 of the full-load current and the CE101 over-limit value does not exceed the set threshold, no specific harmonic compensation setting is required; When the three-phase current does not exceed 1 / 2 of the full load current, specific subharmonic compensation setting is required.

3. The method for suppressing three-phase harmonic current input to ship power supply equipment according to claim 1, characterized in that: The specific process of fundamental current PI loop control for three-phase electricity is as follows: Perform abc / dq transformation on the three-phase current to obtain the d-axis component current and the q-axis component current in the dq coordinate system. Subtract the d-axis component current from the DC voltage loop output reference to obtain the error. Perform fundamental PI control on the error to obtain the controlled output current. Add the voltage feedforward component to the controlled output current to obtain the d-axis component after fundamental PI control. The variable q-axis component current is adjusted according to the reactive power of 0, and the output current is controlled by fundamental wave PI control, plus the voltage feedforward component V q =0 to obtain the q-axis component after fundamental wave PI control, and the d-axis component and q-axis component after fundamental wave PI control are subjected to dq / abc inverse transformation and SPWM modulation and then output to the main power circuit unit of the PFC power supply.

4. The method for suppressing three-phase harmonic current input to ship power supply equipment according to claim 1, characterized in that: The specific method for performing fundamental current PI loop control and specific subharmonic compensation control is: The three-phase current is transformed by abc / dq to obtain the dq current in the dq coordinate system, and the dq current is respectively subjected to fundamental current PI control while performing specific harmonic compensation control, and the dq current output by the fundamental current PI control and the dq current output by the specific harmonic compensation control are added together, and then a voltage feedforward component is added, and the dq current with the voltage feedforward component is subjected to dq / abc inverse transformation and SPWM modulation, and then output to the main power circuit unit of the PFC power supply.

5. The method for suppressing three-phase harmonic current input to ship power supply equipment according to claim 1, characterized in that: The complete process of fundamental current PI loop control and specific subharmonic compensation control is: Perform abc / dq transformation on the three-phase current to obtain the d-axis component current i in the dq coordinate system d and the q-axis component current i q , DC voltage loop output reference i dref Subtract the d-axis component current i d Get the error amount i d_err , error amount i d_err Perform fundamental wave PI control to obtain i d1_out , while the error i d_err After the 6th / 12th / 18th / 24th / 30th harmonic compensation control, the specific harmonic controller output i is obtained by adding d_nthout , the specific subharmonic controller output i d_nthout The i obtained by fundamental wave PI control d1_out Added as the d-axis current loop control output i dout , plus the voltage feedforward component V d , sent to the dq / abc inverse transformation; q-axis component current i q According to the reactive power being 0, the fundamental wave PI is used to adjust i q1_out , obtained by a specific subharmonic compensation controller q_nthout ,i q_nthout with i q1_out The sum is the q-axis current loop control output i qout , plus the voltage feedforward component V q =0, and sent to dq / abc inverse conversion; the current after dq / abc inverse conversion is modulated by PWM and sent to the main power circuit unit of the PFC power supply.

6. The method for suppressing three-phase harmonic current input to ship power supply equipment according to claim 1, characterized in that: A second-order resonant controller is used to perform specific harmonic compensation control. The 3rd to 9th harmonics are suppressed by the 6th harmonic compensation, the 9th to 15th harmonics are suppressed by the 12th harmonic compensation, the 15th to 21st harmonics are suppressed by the 18th harmonic compensation, the 21st to 27th harmonics are suppressed by the 24th harmonic compensation, and the 27th to 33rd harmonics are suppressed by the 30th harmonic compensation.

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