Optimization method for grid-side electric energy quality in frequency conversion and speed regulation device of mining grouting pump

Abstract

The method comprises the following steps: by analyzing motion characteristics and a load curve of a well drilling water injection pump, revealing a beat frequency phenomenon induced by load torque ripple of a motor, and determining that the load torque ripple is a fundamental cause for causing DC bus voltage ripple and network side electric energy quality deterioration; on the basis, an active power decoupling circuit which is compact in structure and simple in capacity is designed, two working modes of Boost and Buck are configured to realize grid-side electric energy quality optimization, and a corresponding control method of the decoupling circuit is designed; and finally, a system simulation model is constructed based on an MATLAB / Simulink platform, the proposed optimization technology and a traditional scheme are compared and analyzed, and the superiority of the technology in the aspect of improving the grid-side electric energy quality of the frequency conversion speed regulation control device for the water injection pump is verified.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of grouting equipment, and particularly relates to a method for optimizing power quality on the grid side of a frequency conversion speed regulating device of a mine-used grouting pump. BACKGROUND

[0002] For the motor, the pulsating load will cause torque pulsation, resulting in direct current bus voltage pulsation. The high-order harmonic current generated by modulation will enter the motor, causing additional vibration, noise and heat, and damaging the service life of the motor. The direct current bus voltage pulsation will also cause grid current distortion, polluting the power grid, and affecting other electrical equipment in the water injection pump system power supply area. By injecting a component with the same frequency as the grid into the motor q-axis voltage, the motor output power follows the output power of the standard single-phase grid, thereby improving the grid current THD. However, this method may increase the bus voltage pulsation, which is not conducive to the stable operation of the motor. In the engineering applications in the oil, natural gas, coal and other industries, the motor output power is affected by the pump, and it is impossible to completely follow the ideal grid power, so this method cannot be directly applied. Another solution is to use power decoupling technology to guide the pulsating power in the motor system into an auxiliary circuit, i.e. a power decoupling circuit. According to the installation position of the power decoupling circuit, the power decoupling technology can be divided into parallel power decoupling circuit and series power decoupling circuit.

[0003] In the prior art, the power decoupling circuit adopts a capacitor scheme, such as the power converter without electrolytic capacitor for permanent magnet synchronous motor and the control method thereof disclosed in Chinese Patent Publication No. CN115242103 A, wherein the pulsating power buffer circuit controls the grid pulsating power to achieve complementary voltage of unequal value thin film capacitor, and suppresses the direct current bus voltage pulsation. Through analysis, the prior art technology adopts double-loop control (grid current inner loop + bus voltage outer loop), which needs to control the grid current phase (to achieve high power factor) and C1, C2 voltage ripple complementation at the same time. The control logic is more complex, and it focuses on the performance optimization of general scenarios. The core problem is that the pulsating power under the condition of no electrolytic capacitor cannot be buffered by a small-capacity capacitor, resulting in periodic fluctuations of the bus voltage, which further affects the motor torque pulsation and grid current harmonics. The above-mentioned prior art features a general decoupling circuit solution to the bus voltage pulsation problem. The pulsating power mainly comes from the instantaneous difference between the grid and the motor power. The above strategy is suitable for low-inertia loads. For specific industrial equipment such as mine grouting pumps, the load is a plunger pump, which has the characteristics of strong pulsation and high mechanical inertia (load torque fluctuation range 0~rated torque, mechanical inertia J=5.327 kg•m 2), the core contradiction is the load torque pulsation caused by the mechanical structure of the plunger pump, and then the beat frequency phenomenon and the grid-side power quality problem are caused, and there is no good solution for the above prior art at present; Based on this, the application designs a mine grouting pump frequency conversion speed regulating device grid-side power quality optimization method. SUMMARY

[0004] The purpose of the application is to solve the problems in the prior art, and a mine grouting pump frequency conversion speed regulating device grid-side power quality optimization method is proposed, which mainly includes: A mine grouting pump driving system includes a power decoupling circuit, the power decoupling circuit includes: Bus capacitor C dc The bus capacitor C dc Connected to bus voltage U dc ; Decoupling inductance L x ; Decoupling capacitor C dc1 ; Two complementary working switch tubes S1 and S2; Wherein, the circuit includes Boost mode and Buck mode; Wherein when U dc > U dmin , wherein U dmin Is the critical voltage of working switch, in Boost mode, at this time the switch state S1S2=01, the decoupling inductance L x Absorbs energy from the decoupling capacitor C dc1 , realizes power storage; Wherein when U dc <U dmin , in Buck mode, at this time the switch state S1S2=10, the bus capacitor C dc Through switch tube S1 to L x And C dc1 Power supply, then when the switch state S1S2=01, the inductance L x Through the capacitor C dc1S2 anti-parallel diode freewheeling and feeding the inverter and bus capacitor C dc1 injection power.

[0005] In the above drive system, the decoupling capacitor C dc1 With 2mF, bus capacitor C dc With 8.2mF.

[0006] In the above drive system, the drive system is a motor drive system powered by a three-phase uncontrolled rectifier bridge, and the bus voltage U dc Contains 6 ω g And its integer multiple of pulsating component, can be expressed as:

[0007] Wherein k 1, 2, 3, 4, 5, 6, V dc0 The bus average voltage, V m Can be expressed as V m =π / 3* V dc0 Ignoring the effect of the grid side filter, it can be approximately considered that the instantaneous voltage of the DC bus is the phase-phase voltage difference of the phase that is turned on at that time. When the load torque is greatly pulsating, it will cause the bus voltage to produce a ripple voltage with the same frequency as the load mechanical angle frequency ω m The bus voltage can be further expressed as:

[0008] In the formula, V mu The 6th ripple voltage amplitude caused by three-phase uncontrolled rectification, V mT The voltage ripple amplitude caused by load pulsation, φ 1 and φ 2 are the initial phases of the two pulsating components, respectively. According to the pulse width modulation theory, the three-phase voltage u a , u b , u c Is:

[0009] Substitute equation (21) into equation (22) to get the phase voltage u a( t The expression of ) (4) The right side of the above equation contains the frequency. ω e The fundamental frequency voltage, a pair with 6 ω g The beat frequency voltage term centered on the center, and a pair of terms with ω m The beat frequency voltage terms centered on the torque will cause torque and speed pulsations.

[0010] The control method for the power decoupling circuit in the aforementioned mine grouting pump drive system was also disclosed, utilizing the bus voltage difference. ΔV dc2 Generate pulsating power compensation and directly calculate the decoupling capacitance using coordinate transformation. C dc1 The voltage reference value, the specific steps include: From the formula: ΔV dc2 = U dc - U dc* in U dc* This is the reference value for bus voltage. U dc This is the measured value of the bus voltage; Bus voltage difference ΔV dc2 The pulsating power compensation amount is obtained through pulsating voltage loop control. ΔP rp* It is related to the calculated pulsating voltage. P rp The summation yields the pulsating voltage reference value. P rp* Among them, pulsating power P rp Defined as:

[0011] In the formula, P 2 and φ 1 represents the pulsating power amplitude and initial phase under rated load, respectively; Define the decoupling capacitor voltage V dc1 and decoupling inductor current I lx The expression is as follows

[0012] The formula contains: I lxm = ω · C dc1 · V dc1m Assuming the pulsating power P rp is all absorbed by the active power decoupling circuit, then P rp = V dc1 · I lx , the equation is solved to get

[0013] In the formula, ω = ω m / 2, a =3p / 4; Because there is a certain phase difference between the pulsating power and the capacitor voltage U dc1 , the orthogonal component is constructed P rp* , and the capacitor voltage reference value is obtained by coordinate transformation V dc1* , and the coordinate transformation matrix is

[0014] In the formula, V dc1m is the amplitude of the capacitor voltage V dc1 ; Then the decoupling capacitor voltage controller is designed G cv for

[0015] In the formula, K 1, ω z1 , ω z2 are proportional gain, zero and pole, K 1affect the cut-off frequency of the voltage control loop, ω z1 , ω z2 are used to improve the phase margin and suppress high-frequency noise, respectively.

[0016] In the control method of the above power decoupling circuit, the control object of the pulsating voltage loop G rs can be derived as

[0017] In the formula, k =2 / C dc2 , p =2 / RC dc2 Therefore, a controller can be designed. G c for:

[0018] in, K 0 represents the proportional gain. ω z0 Zero frequency, ω p0 The frequency is the pole frequency.

[0019] In the control side of the aforementioned power decoupling circuit, a pulsating voltage loop controller is configured. G c Gain K 0 is 0.05, zero frequency ω z0 The pole frequency is 10 rad / s. ω p0 It is 2000 rad / s.

[0020] In the control scheme of the above power decoupling circuit, the parameters of the decoupling capacitor voltage controller Gcv are set as K1=0.11, ωz1=100rad / s, and ωp1=10000rad / s.

[0021] A method for optimizing the grid-side power quality in a variable frequency speed control device for a mining grouting pump is proposed, which utilizes the aforementioned power decoupling circuit control method to optimize the grid-side power quality.

[0022] This paper proposes a grid-side power quality optimization technique for a variable frequency speed control device for water injection pumps, and establishes a MATLAB / Simulink model for simulation testing. Compared with traditional control methods, it has the following advantages: 1) This invention analyzes the motion characteristics and load curves of drilling water injection pumps, analyzes the beat frequency phenomenon caused by motor load torque pulsation, and points out that the load torque pulsation is the root cause of DC bus voltage pulsation and grid-side current distortion. It adopts a simplified topology of "single inductor + single capacitor" (Lx + Cdc1) and achieves Boost / Buck dual-mode switching through the complementary operation of two switching transistors. It has the advantages of low cost, high reliability, and suitability for the harsh environment of mining equipment.

[0023] 2) The decoupling circuit control method designed by the application, compared with the general electrolytic capacitor-free scheme in the prior art, generates pulsating power compensation through bus voltage difference AVdc2, directly calculates decoupling capacitor voltage reference value through coordinate transformation, and does not need complex current closed-loop control, thereby adapting to the high reliability requirement of mining equipment.

[0024] 3) The application effectively reduces the pulsation of bus voltage under water injection pump load and the harmonic of grid-side current, ensures that the harmonic distortion rate of grid-side current meets the operation requirement, and reduces the risk of failure of water injection pump variable frequency speed control device and auxiliary equipment. Compared with the traditional control mode, under the same conditions, the bus voltage fluctuation is reduced from the original 80V low-frequency pulsation to 43V, the output torque waveform also becomes smoother, the speed fluctuation is reduced from the original 15rpm to 0.71rpm, and according to the FFT analysis of current ia, the grid-side input phase current iaTHD is reduced from the original serious distortion of 11.66% to 4.65%.

[0025] 4) For the specific load (strong pulsation, high inertia) of the mining grouting pump, through the analysis of beat frequency mechanism and the active power decoupling scheme with simplified structure and simplified control, the reliability and economy requirement of industrial equipment is adapted while ensuring the optimization of grid-side power quality, and compared with the general decoupling circuit scheme in the prior art, the application has outstanding specific advantages and significant progress. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of a motor drive system with power decoupling function in a mining grouting pump variable frequency speed regulation device disclosed by the application.

[0027] Figure 2 It is a bus voltage and motor output power, torque and speed schematic diagram in a mining grouting pump.

[0028] Figure 3 It is a bus voltage and grid-side current waveform diagram when the power decoupling circuit in a mining grouting pump is not working.

[0029] Figure 4 It is a schematic diagram of two working modes Boost and Buck of the power decoupling circuit.

[0030] Figure 5 It is a decoupling power control block diagram.

[0031] Figure 6 It is a bus pulsating voltage control unit schematic diagram.

[0032] Figure 7 It is a pulsating voltage control bode diagram.

[0033] Figure 8is the decoupling capacitor voltage control bode diagram.

[0034] Figure 9 is the simulation waveform of the motor with pump load when the power decoupling circuit is not working.

[0035] Figure 10 is the simulation waveform of the motor with pump load when the active power decoupling circuit is working. DETAILED DESCRIPTION

[0036] REFERENCE Figures 1-10 In the present application, the motion characteristics and load characteristics of the water injection pump are analyzed, the beat frequency effect induced by load torque pulsation is clarified, the working mechanism of the active power decoupling circuit is analyzed, and a grid-side power quality optimization method based on active power decoupling for the variable frequency speed regulation control device of the water injection pump is constructed, wherein: First, the beat frequency phenomenon under load torque pulsation is studied.

[0037] The bus voltage of the motor drive system supplied by the three-phase uncontrolled rectifier bridge contains 6 ω g and its integer multiple pulsating components, which can be expressed as (1) wherein k 1, 2, 3, 4, 5, and 6 in a power frequency cycle, V dc0 is the bus average voltage, V m which can be expressed as V m =π / 3* V dc0 Ignoring the effect of the grid-side filter, the instantaneous DC bus voltage can be approximately considered as the phase-phase voltage difference of the phase that is turned on at that time. When the load torque pulsates greatly, it will cause the bus voltage to produce ripple voltage with the same frequency ω m as the load mechanical angular frequency (2) wherein V mu is the 6th ripple voltage amplitude caused by three-phase uncontrolled rectification, V mT is the voltage ripple amplitude caused by load pulsation, φ 1 and φ 2 are the initial phases of the two pulsating components, respectively. According to the pulse width modulation theory, the three-phase voltage u a , u b , uc For (3) Substitute equation (21) into equation (22) to get the phase voltage u a ( t ) of equation (22) (4) The right side of the above equation contains the fundamental voltage with frequency ω e , a pair of beat frequency voltage terms centered at 6 ω g , and a pair of beat frequency voltage terms centered at ω m , which will cause torque, speed pulsation.

[0038] Second step, design active power decoupling circuit.

[0039] At this time, the relationship between bus voltage and pulsating power, torque, speed under rated operating condition is shown in Figure 2 . The motor output power P o and output torque T e remain synchronous with the load cycle, while the bus voltage lags behind the load change, but maintains the same load change cycle, and the load change cycle is determined by the motor mechanical angular velocity ω m .

[0040] The motor output torque varies greatly between 0 T n , resulting in a large pulsating power. Since the mechanical inertia of the pump load is very large, the motor angular velocity ω m remains essentially unchanged under rated operating condition, and the output torque T e is positively correlated with the motor output power P o . P rp= P o -P n / 2 When the pulsating power is greater than 0, the bus capacitor absorbs the pulsating power, and the bus voltage rises. When the pulsating power is less than 0, the bus capacitor releases excess power, and the bus voltage drops. P rp P rp

[0041] The motor drive system with power decoupling function is as follows​​Figure 1 The rectifier side uses a three-phase diode bridge, and the grid side power P g is equal to the compensation power P DSC and the input power of the inverter. The bus voltage and grid side current waveform when the power decoupling circuit is not working are shown in P inv . Figure 3

[0042] U dmin A critical voltage for switching the working mode of the decoupling circuit, and a safe limit for ensuring the inverter working in the linear modulation region. When the bus voltage is detected to be greater than u dc , U dmin , the power decoupling circuit runs and works in the Boost mode, and the grid side power will partly flow to the power decoupling circuit, which will be stored in the decoupling capacitor. When the bus voltage is detected to be less than u dc , U dmin , the power decoupling circuit runs normally and works in the Buck mode, and injects power to the inverter and bus capacitor C dc1 . At this time P DSC , P inv , the bus voltage will be maintained around U dmin .

[0043] The two working modes of the power decoupling circuit are shown in Figure 4 , S1 and S2 work complementarily. In the Boost mode, when the switch state S1S2=01, the inductor L x absorbs energy from the decoupling capacitor C dc1 , and then S1S2=10, the decoupling capacitor and the decoupling inductor release energy to the bus capacitor C dc together. In the Buck mode, when S1S2=10, the bus capacitor C dc is supplied by the switch S1 to L x and C dc1 , and then when the switch state S1S2=01, the inductor L x charges the capacitor C dc1 , and S2 anti-parallel diode freewheels.​

[0044] A power decoupling control method without LC branch current sensor is proposed in this paper, as shown in Fig. 1. Figure 5

[0045] - ΔV dc2 = U dc - U dc* where U dc* is the bus voltage reference value, U dc is the measured bus voltage value, the bus voltage difference is controlled by the ripple voltage to obtain the ripple power compensation ΔP rp* , which is added to the calculated ripple voltage P rp to obtain the ripple voltage reference value P rp* , where the ripple power P rp is defined as: (5) where P 2 and φ 1 are the amplitude and initial phase of the ripple power under rated load, respectively.

[0046] The decoupling capacitor voltage V dc1 and the decoupling inductor current I lx are defined as (6) where I lxm = ω · C dc1 · V dc1m .

[0047] Assuming that all the ripple power P rp is absorbed by the active power decoupling circuit, then P rp = V dc1 · I lx , and the equation is solved to obtain (7) where ω = ω m / 2,​a =3p / 4.

[0048] Since the pulsating power and the capacitor voltage U dc1 There is a certain phase difference, so the P rp* The orthogonal component is constructed, and the capacitor voltage reference value is obtained by coordinate transformation V dc1* The coordinate transformation matrix is (8) In the formula, V dc1m is the amplitude of the capacitor voltage V dc1 .

[0049] Then design the decoupling capacitor voltage controller G cv (9) In the formula, K 1, ω z1 , ω z2 are the proportional gain, zero and pole respectively. K 1The cutoff frequency of the voltage control loop, ω z1 , ω z2 are used to improve the phase margin and suppress high-frequency noise respectively.

[0050] The bus pulsating voltage control block diagram is shown in Figure 6 The control object of the pulsating voltage loop G rs can be derived as (10) In the formula, k =2 / C dc2 , p =2 / RC dc2 . Thus, the controller G c can be designed as (11) Figure 7 The Bode diagram of the closed-loop ripple voltage control is drawn, and the gain G c of the pulsating voltage controller K 0 is 0.05, and the zero frequency ω ​z0 = 10 rad / s, pole frequency ω p0 = 2000 rad / s. After compensation, the amplitude gain at 10.5 Hz is increased to 99 db, which reduces the steady-state tracking error. The crossover frequency is set at 255 Hz. The phase margin is equal to 56.1°, which guarantees the stability of the system.

[0051] Setting parameters of decoupling capacitor voltage controller Gcv K 1 = 0.11, ω z1 = 100 rad / s, and ω p1 = 10000 rad / s, in Figure 8 The bode plot of the capacitor voltage control loop can be plotted in Fig. 6, where the uncompensated frequency response shows an undesirable performance because the phase margin is close to 0. After compensation, the frequency response is significantly improved. The crossover frequency is set at 1230 Hz, and the phase margin is equal to 51.6°.

[0052] Step 3, design a decoupling scheme based on parallel power.

[0053] The simulation parameters are shown in Table 1, the bus voltage is 8.2 mF capacitor, the decoupling capacitor C dc1 is set to 2 mF, which is used to buffer the pulsating power in the system and reduce the bus voltage pulsation. The motor drive system is based on speed-current double closed loop field oriented control (FOC) scheme, and the power decoupling control strategy based on Fig. 5 is adopted.

[0054] Table 1 Simulation Parameters Table 1 Simulation Parameters

[0055] The simulation waveforms of the motor with pulsating load are shown in Fig. 7, where the periodic fluctuation of the load torque appears, Figure 9 (a) the load torque appears low frequency pulsation, and the torque jitter is serious, the torque fluctuation range is from 0 to the rated torque, about 3350 N.m. Since the system has a large mechanical inertia, Figure 9 (b) the load torque appears low frequency pulsation, and the torque jitter is serious, the torque fluctuation range is from 0 to the rated torque, about 3350 N.m. Since the system has a large mechanical inertia, Figure 9 (a) the load torque appears low frequency pulsation, and the torque jitter is serious, the torque fluctuation range is from 0 to the rated torque, about 3350 N.m. Since the system has a large mechanical inertia, N r is the actual speed, the speed pulsation is obviously smaller than the torque pulsation, the speed fluctuation is 15 rpm, N r_ob is the SMO observed speed, which can well track the actual speed. The Figure 9The motor output power in (g) has a large fluctuation with a period of about 0.095s. This makes the bus capacitor have a low-frequency fluctuation of 80V, and the bus capacitor forms a loop with the power grid and the filter, resulting in a serious distortion of the input current of the power grid i a The FFT analysis shows that the THD is as high as 11.66%.

[0056] The simulation waveform of the motor with a pump load when the decoupling circuit is working is shown in Figure 10 Under the action of the power decoupling circuit, the fluctuating power in the system is absorbed by the decoupling capacitor C dc1 , so that the bus voltage has a "cut bottom" phenomenon, u dmin is set to 487V, and the minimum bus voltage is greater than 487V due to the power decoupling control. Compared with the minimum voltage of the bus voltage in Figure 9 , the maximum bus voltage is basically unchanged, and finally the bus voltage fluctuation is reduced to 43V, the output torque waveform becomes smoother, the speed fluctuation is reduced to 0.71rpm, and the THD of the input phase current i a of the power grid is reduced to 4.65%.

[0057] It can be known from common technical knowledge that the present application can be realized by other embodiments without departing from the spirit or essential characteristics thereof. Therefore, the above disclosed embodiments are only examples and are not the only ones. All changes within the scope of the present application or within the scope equivalent to the present application are included in the present application.

Claims

1. A grouting pump drive system for mining, characterized in that, Includes a power decoupling circuit, the power decoupling circuit comprising: Bus capacitor C dc The bus capacitor C dc Connected to bus voltage U dc ; Decoupling inductor L x ; Decoupling capacitor C dc1 ; Two complementary switching transistors, S1 and S2; The circuit includes Boost mode and Buck mode; Where U dc >U dmin U dmin The critical voltage for switching operation is at the Boost mode, where the switching states S1S2 = 0 and 1, and the decoupling inductor L... x Absorption from decoupling capacitor C dc1 The energy is used to achieve power storage; Where U dc dmin In Buck mode, the switch states S1S2 = 10, and the bus capacitor C... dc via switch S1 to L x and C dc1 Power is supplied, and then when the switch state S1S2=01, the inductor L x Through capacitor C dc1 The S2 anti-parallel diode freewheels and supplies current to the inverter and bus capacitor C. dc1 Injected power.​ 2. The mining grouting pump drive system according to claim 1, characterized in that, The decoupling capacitor C dc1 Using 2mF, bus capacitor C dc 8.2mF is used.

3. The mining grouting pump drive system according to claim 1, characterized in that, The drive system is a motor drive system powered by a three-phase uncontrolled rectifier bridge, and its bus voltage U dc Contains 6ω g The pulsating components, and their integer multiples thereof, can be expressed as: Where k represents 1, 2, 3, 4, 5, 6, V within one power frequency cycle. dc0 It is the average bus voltage, V m It can be represented as V m =π / 3*V dc0 Ignoring the effect of the grid-side filter, the instantaneous DC bus voltage can be approximated as the phase-to-phase voltage difference at the time of conduction. When the load torque fluctuates significantly, it will cause the bus voltage to generate a frequency ω that is related to the mechanical angular frequency of the load. m For ripple voltages at the same frequency, the bus voltage can be further expressed as: In the formula, V mu V represents the amplitude of the 6th ripple voltage caused by the three-phase uncontrolled rectification. mT This represents the voltage ripple amplitude caused by load fluctuations. and These are the initial phases of the two pulsating components. According to pulse width modulation theory, the three-phase voltage u a u b u c for: Substituting equation (21) into equation (22) yields the phase voltage u. a The expression for (t) The right side of the above equation contains a frequency of ω. e The fundamental frequency voltage, a pair with 6ω g The beat frequency voltage term centered on ω, and a pair of terms with ω m The beat frequency voltage terms centered on the torque will cause torque and speed pulsations.

4. A control method for a power decoupling circuit, characterized in that, The power decoupling circuit control in the mine grouting pump drive system of claims 1 to 3 is achieved through the bus voltage difference ΔV. dc2 Generate the pulsating power compensation value, and directly calculate the decoupling capacitance C using coordinate transformation. dc1 The voltage reference value, the specific steps include: From the formula: ΔV dc2 =U dc -U dc* U dc* U is the reference value for bus voltage. dc This is the measured value of the bus voltage; Bus voltage difference ΔV dc2 The pulsating power compensation amount ΔP is obtained through pulsating voltage loop control. rp* It is related to the calculated pulsating voltage P. rp The summation yields the pulsating voltage reference value P. rp* Among them, the pulsating power P rp Defined as: In the formula, P2 and These represent the pulsating power amplitude and initial phase under rated load, respectively; Define the decoupling capacitor voltage V dc1 and decoupling inductor current I lx The expression is as follows The formula contains: I lxm =ω·C dc1 ·V dc1m Assuming the pulsating power P rp If all of it is absorbed by the active power decoupling circuit, then P rp =V dc1 ·I lx Solving the equation yields In the formula, ω=ω m / 2, a = 3p / 4; Due to the pulsating power and capacitor voltage U dc1 There is a certain phase difference, therefore P rp* Construct orthogonal components and perform coordinate transformation to obtain the capacitor voltage reference value V. dc1* The coordinate transformation matrix is In the formula, V dc1m It is the capacitor voltage V dc1 The amplitude; Then, a decoupling capacitor voltage controller G is designed. cv for In the formula, K1, ω z1 ω z2 These represent the proportional gain, zeros, and poles, respectively. K1 affects the cutoff frequency of the voltage control loop, ω. z1 ω z2 These are used to improve phase margin and suppress high-frequency noise, respectively.

5. The control method for the power decoupling circuit according to claim 1, characterized in that, The control object G of the pulsating voltage loop rs It can be deduced as In the formula, k = 2 / C dc2 p = 2 / RC dc2 Therefore, a controller G can be designed. c for: Where K0 is the proportional gain, ω z0 ω is the zero-point frequency. p0 is the pole frequency.

6. The control method for the power decoupling circuit according to claim 1, characterized in that, Configure the pulsating voltage loop controller G c The gain K0 is 0.05, and the zero frequency ω z0 The pole frequency is 10 rad / s. p0 It is 2000 rad / s.

7. The control method for the power decoupling circuit according to claim 2, characterized in that, Set the parameters K1 = 0.11 for the decoupling capacitor voltage controller Gcv, ω z1 =100 rad / s, and ω p1 =10000rad / s.

8. A method for optimizing the power quality on the grid side of a variable frequency speed control device for a mining grouting pump, characterized in that; The power quality on the grid side is optimized by using the control method of the power decoupling circuit according to any one of claims 4 to 7.

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