Multiple variable pitch servo driver common bus energy equalizer

Abstract

The utility model discloses a plurality of variable pitch servo driver common bus energy equalizer is by n group isolation drive protection circuit group, n group switch control module group, n group isolation resistance diode group, n group capacitor group, n rectifier diode, isolation voltage sampling circuit, power supply circuit and MCU control unit composition. The utility model discloses through the ingenious control to the switch control module of multiple reverse series connection, has realized the common bus operation of plurality of variable pitch driver bus, and the electric energy between each bus can be self -adaptation and balanced two -way deployment and full use, reduces the configuration of variable pitch driver brake resistance and reduces the heat generation, improves system reliability.

Description

Technical Field

[0001] This utility model relates to the field of pitch servo drive technology, specifically to a common bus energy equalizer for multiple pitch servo drives. Background Technology

[0002] Wind energy is a renewable and clean energy source, and wind turbines have broad application prospects. Wind turbines typically use multiple pitch servo drives and servo motors to dynamically adjust the blade angle of attack to obtain optimal wind energy in real time, and adjust the blades to a safe angle to ensure the safety of the wind tower during abnormal weather. The power circuit of the pitch servo drive is as follows: it obtains three-phase 380V-AC power from the grid, which is then rectified by a three-phase bridge full-wave rectifier and filtered by capacitors to form DC power. The DC power on the bus is inverted and outputs corresponding three-phase currents to control the operation of the servo motor. When the pitch servo motor is in generating mode, the electrical energy fed into the bus will cause the bus voltage to rise. The pitch servo drive must conditionally turn on the power switch and dissipate the electrical energy through the braking resistor to avoid damage to the equipment due to excessive bus voltage. When a single pitch servo drive operates independently, the electrical energy fed into the bus by the servo motor can only be dissipated through the braking resistor of the servo drive. Therefore, the braking resistor equipped with the servo drive has problems such as high power, large size and high cost, and the consumption of electrical energy will cause the ambient temperature of the equipment to rise. If multiple servo drives share a common bus, the electrical energy fed into the bus by the servo motor can be allocated and used by multiple drives, reducing the probability of bus voltage rise and energy loss through braking resistors. This can correspondingly reduce the power, size, and cost of the braking resistors. Therefore, servo pitch drives operating on a common bus have advantages over operating on independent buses.

[0003] There are three common busbar connection methods: direct busbar connection, contactor-switched busbar connection, and busbar connection via an Active Front End (AFE) rectifier unit. However, when used with multiple servo pitch drives sharing a busbar, the following drawbacks exist: When multiple pitch servo drives are directly and fixedly connected by the busbar, a failure in one will cause abnormal busbar voltage, rendering other pitch drives inoperable. This prevents the wind turbine blades from reaching a safe angle, increasing the risk of tower collapse and reducing the reliability of the pitch system. While contactor-switched busbar connection can isolate a faulty pitch drive from the common busbar, the contactor switching speed is slow (typically tens to hundreds of milliseconds), making it easy for the fault to spread to other pitch drives. Furthermore, the contactor's switching action generates an electric arc, which can endanger adjacent components within the control cabinet, further reducing the reliability of the pitch system. An AFE (Automatic External Circuit) is a high-performance rectification method that uses PWM closed-loop control of IGBTs to achieve bidirectional energy flow. It can rectify the AC power from the grid and send it to the DC bus for the load, and it can also invert the energy fed into the DC bus from the load into AC power of the same frequency and phase to feed back to the grid. However, the power circuit of a standard pitch servo drive already has a rectification and filtering unit. Adding an AFE of equivalent capacity for common bus operation would be unsuitable in terms of cost, size, and control complexity for multiple servo pitch drives operating on a common bus. Utility Model Content

[0004] The present invention aims to solve the problems of low reliability and high cost in realizing the common connection of multiple pitch drive buses, and provides an energy equalizer for multiple pitch servo drives sharing a common bus.

[0005] To solve the above problems, this utility model is achieved through the following technical solution:

[0006] A common bus energy equalizer for multiple pitch servo drives consists of n groups of isolated drive protection circuits, n groups of switch control modules, n groups of isolation diodes, n groups of capacitors, n rectifier diodes, an isolation voltage sampling line, a power supply circuit, and an MCU control unit.

[0007] The i-th isolation drive protection circuit group corresponds to the i-th pitch driver, including one front isolation drive protection circuit Ui and one rear isolation drive protection circuit U(i+n); the i-th switch control module group corresponds to the i-th pitch driver, including a front switch control module Qi and a rear switch control module Q(i+n); the i-th isolation diode group corresponds to the i-th pitch driver, including a front isolation diode Di and a rear isolation diode D(i+n); the i-th capacitor group corresponds to the i-th pitch driver, including an absorption capacitor Ci and a buffer capacitor C(i+n); the i-th rectifier diode DXi corresponds to the i-th pitch driver.

[0008] Each front switch control module Qi includes a front switch transistor and a front freewheeling diode. The gate of the front switch transistor forms the gate of the front switch control module Qi. The anode of the front freewheeling diode is connected to the emitter of the front switch transistor to form the emitter of the front switch control module Qi. The cathode of the front freewheeling diode is connected to the collector of the front switch transistor to form the collector of the front switch control module Qi.

[0009] Each post-switch control module Q(i+n) includes a post-switch transistor and a post-current diode. The gate of the post-switch transistor forms the gate of the post-switch control module Q(i+n). The anode of the post-current diode is connected to the emitter of the post-switch transistor to form the emitter of the post-switch control module Q(i+n). The cathode of the post-current diode is connected to the collector of the post-switch transistor to form the collector of the post-switch control module Q(i+n).

[0010] The positive terminal Ci+ of the i-th pitch driver bus is connected to the collector of the front switch control module Qi; the negative terminal Ci- of the i-th pitch driver bus is connected to the connection point of the buffer capacitor C(i+n) and the absorption capacitor Ci; the pitch driver status signal BHi output terminal of the i-th pitch driver is connected to the different pitch driver status signal BHi input terminals of the MCU control unit; the communication terminals of all pitch drivers are connected to the communication terminal of the MCU control unit.

[0011] The positive terminal Ci+ of the i-th pitch driver bus is connected to the anode of the rectifier diode DXi, and the cathode of the rectifier diode DXi is connected to the positive terminal CV+ of the pitch driver bus of the power supply circuit; the negative terminal Ci- of the i-th pitch driver bus is connected to the negative terminal CV- of the pitch driver bus of the power supply circuit; the digital power supply VCC output terminal of the power supply circuit is connected to the digital power supply VCC input terminal of the MCU control unit; the analog power supply Vdd output terminal of the power supply circuit is connected to the analog power supply Vdd input terminal of the MCU control unit; the power status signal DY output terminal of the power supply circuit is connected to the power status signal DY input terminal of the MCU control unit; the 2n isolated drive power supply V1~V2n output terminals of the power supply circuit are respectively connected to the isolated drive power supply V1~V2n input terminals of different MCU control units;

[0012] The power ground terminal GND of the MCU control unit is connected to the power ground terminal GND of the front isolation drive protection circuit Ui; the control signal Gi output terminal of the MCU control unit is connected to the control signal Gi input terminal of the front isolation drive protection circuit Ui; the overcurrent protection status signal Fi output terminal of the front isolation drive protection circuit Ui is connected to the overcurrent protection status signal Fi input terminal of the MCU control unit; the power ground terminal GNDi of the front isolation drive protection circuit Ui is connected to the emitter of the front switch control module Qi; the drive signal Qi-G output terminal of the front isolation drive protection circuit Ui is connected to the gate of the front switch control module Qi; the saturation voltage BVi sampling terminal of the front isolation drive protection circuit Ui is connected to the anode of the front isolation diode Di, and the cathode of the front isolation diode Di is connected to the collector of the front switch control module Qi;

[0013] The power ground terminal GND of the MCU control unit is connected to the power ground terminal GND of the rear isolation drive protection circuit U(i+n); the output terminal of the control signal G(i+n) of the MCU control unit is connected to the input terminal of the control signal G(i+n) of the rear isolation drive protection circuit U(i+n); the output terminal of the overcurrent protection status signal F(i+n) of the rear isolation drive protection circuit U(i+n) is connected to the input terminal of the overcurrent protection status signal F(i+n) of the MCU control unit; the power ground terminal GND(i+n) of the rear isolation drive protection circuit U(i+n) is connected to the emitter of the rear switch control module Q(i+n); the output terminal of the drive signal Q(i+n)-G of the rear isolation drive protection circuit U(i+n) is connected to the gate of the rear switch control module Q(i+n); the sampling terminal of the saturation voltage BV(i+n) of the rear isolation drive protection circuit U(i+n) is connected to the anode of the diode D(i+n), and the cathode of the rear isolation diode D(i+n) is connected to the collector of the rear switch control module Q(i+n);

[0014] The collector of the front switch control module Qi is connected to the positive terminal Ci+ of the bus of the i-th pitch driver and one end of the absorption capacitor Ci. The emitter of the front switch control module Qi is connected to the emitter of the rear switch control module Q(i+n). The collector of the rear switch control module Q(i+n) is connected to one end of the buffer capacitor C(i+n). The other end of the absorption capacitor Ci is connected to the other end of the buffer capacitor C(i+n).

[0015] The collector of the front switch control module Qi is connected to the positive voltage VCI input terminal of the i-th pitch driver bus of the isolation voltage sampling line; the collector of the rear switch control module Q(i+n) is connected to the positive voltage HV+ input terminal of the common bus of the isolation voltage sampling line; the connection point of the buffer capacitor C(i+n) and the absorption capacitor Ci is connected to the negative voltage HV- input terminal of the common bus of the isolation voltage sampling line; the output terminal of the positive voltage VCI of the i-th pitch driver bus of the isolation voltage sampling line is connected to the positive voltage input terminal VCI of the pitch driver bus of the MCU control unit; the output terminal of the positive voltage HV+ of the common bus of the isolation voltage sampling line is connected to the positive voltage HV+ input terminal of the common bus of the MCU control unit; the output terminal of the negative voltage HV- of the common bus of the isolation voltage sampling line is connected to the negative voltage HV- input terminal of the common bus of the MCU control unit.

[0016] In the above, i = 1, 2, ..., n, where n is the number of pitch drives.

[0017] In the above scheme, the front switching transistor of the front switching control module Qi and the rear switching transistor of the rear switching control module Q(i+n) of each group of switching control modules have the same specifications; the front freewheeling diode of the front switching control module Qi and the rear freewheeling diode of the rear switching control module Q(i+n) of each group of switching control modules have the same specifications.

[0018] In the above scheme, all front isolation drive protection circuits and all rear isolation drive protection circuits include the ACPL-332J switching transistor driver chip.

[0019] In the above scheme, the communication terminal of the MCU control unit is also connected to the host computer.

[0020] In the MCU control unit, the control logic relationship of the control signal Gi of the front switch control module Qi corresponding to the i-th pitch driver is as follows:

[0021] Gi=DY&BHi&Fi&(ΔU1i≤ΔU1)&(ΔU2i≤ΔU2)&ENi

[0022] In the MCU control unit, the control logic relationship of the control signal G(i+n) of the rear switch control module Q(i+n) corresponding to the i-th pitch driver is as follows:

[0023] G(i+n)=DY&BHi&F(i+n)&(ΔU1i≤ΔU1)&(ΔU2i≤ΔU2)&ENi

[0024] Wherein, DY represents the power status signal; BHi represents the status signal of the i-th pitch driver; Fi represents the overcurrent protection status signal of the front isolation drive protection circuit Ui, and F(i+n) represents the overcurrent protection status signal of the rear isolation drive protection circuit U(i+n); ΔU1i represents the absolute value of the deviation between the positive voltage VCI of the i-th pitch driver bus and the average value U of the positive voltages VC1 to VCn of all pitch drivers, and ΔU1 represents the first absolute value threshold of the deviation; ΔU2i represents the absolute value of the deviation between the positive voltage VCI of the i-th pitch driver bus and the positive voltage HV+ of the common bus, and ΔU2 represents the second absolute value threshold of the deviation; ENi represents the enable command received by the communication terminal to turn on the corresponding switch control module of the i-th pitch driver; & represents AND logic.

[0025] Compared with the prior art, this utility model has the following characteristics:

[0026] 1. By cleverly controlling multiple sets of reverse-connected series switch control modules, multiple pitch drive buses can operate on the same bus. The electrical energy between each bus can be adaptively and evenly distributed and fully utilized in both directions, reducing the configuration of the pitch drive braking resistor and reducing heat generation, thereby improving system reliability.

[0027] 2. The switch control module group and control logic can be shut down in 3 to 10 microseconds, which can isolate the faulty drive from the common bus faster than contactors or circuit breakers (usually tens to hundreds of milliseconds), without affecting the operation of other pitch drives and better ensuring the safety of the pitch system.

[0028] 3. The structure and control are simple. It does not require the use of a more complex bus common connection mode of the AFE active front-end rectifier unit, which makes it easier for the standard pitch drive to operate on the same bus. It is smaller in size, lower in cost, and easier to apply. Attached Figure Description

[0029] Figure 1 This is an electrical schematic diagram of a common bus energy equalizer for multiple pitch servo drives.

[0030] Figure 2 This is the control timing diagram for the switching control module of the energy equalizer. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific examples and accompanying drawings.

[0032] See Figure 1A common-bus energy equalizer for multiple pitch servo drives is described, comprising n groups of isolated drive protection circuits, n groups of switch control modules, n groups of isolation diodes, n groups of capacitors, n rectifier diodes, an isolation voltage sampling line, a power supply circuit, and an MCU control unit. n represents the number of pitch drives. i = 1, 2, ..., n.

[0033] The i-th group of isolation drive protection circuits corresponds to the i-th pitch driver and includes one front isolation drive protection circuit Ui and one rear isolation drive protection circuit U(i+n). Both the front isolation drive protection circuit Ui and the rear isolation drive protection circuit U(i+n) are ACPL-332J switching transistor driver chips with overcurrent protection and opto-isolation.

[0034] The i-th group of switch control modules corresponds to the i-th pitch driver and includes a front switch control module Qi and a rear switch control module Q(i+n). Each front switch control module Qi includes a front switch transistor and a front freewheeling diode. The gate of the front switch transistor forms the gate of the front switch control module Qi. The anode of the front freewheeling diode is connected to the emitter of the front switch transistor to form the emitter of the front switch control module Qi. The cathode of the front freewheeling diode is connected to the collector of the front switch transistor to form the collector of the front switch control module Qi. Each rear switch control module Q(i+n) includes a rear switch transistor and a rear freewheeling diode. The gate of the rear switch transistor forms the gate of the rear switch control module Q(i+n). The anode of the rear freewheeling diode is connected to the emitter of the rear switch transistor to form the emitter of the rear switch control module Q(i+n). The cathode of the rear freewheeling diode is connected to the collector of the rear switch transistor to form the collector of the rear switch control module Q(i+n). The front switching transistor of the front switching control module Qi and the rear switching transistor of the rear switching control module Q(i+n) in each group of switching control modules have the same specifications. Similarly, the front freewheeling diode of the front switching control module Qi and the rear freewheeling diode of the rear switching control module Q(i+n) in each group of switching control modules have the same specifications. Switching control modules are typically IGBT modules or MOSFET modules that are matched with switching transistors and freewheeling diodes, or they can be functional modules composed of discrete switching transistors and freewheeling diodes with matched current magnitudes and switching speeds.

[0035] The i-th group of blocking diodes corresponds to the i-th pitch driver and includes the front blocking diode Di and the rear blocking diode D(i+n). The i-th group of capacitors corresponds to the i-th pitch driver and includes the absorption capacitor Ci and the buffer capacitor C(i+n). The i-th rectifier diode DXi corresponds to the i-th pitch driver.

[0036] The positive terminal Ci+ of the i-th pitch driver bus is connected to the collector of the front switch control module Qi. The negative terminal Ci- of the i-th pitch driver bus is connected to the junction of the buffer capacitor C(i+n) and the absorption capacitor Ci. The pitch driver status signal BHi output terminal of the i-th pitch driver is connected to the different pitch driver status signal BHi input terminals of the MCU control unit. The communication terminals of all pitch drivers are connected to the communication terminal of the MCU control unit. The communication terminal of the MCU control unit is also connected to the host computer.

[0037] The positive terminal Ci+ of the i-th pitch driver bus is connected to the anode of the rectifier diode DXi, and the cathode of the rectifier diode DXi is connected to the positive terminal CV+ of the pitch driver bus of the power supply circuit. The negative terminal Ci- of the i-th pitch driver bus is connected to the negative terminal CV- of the pitch driver bus of the power supply circuit. The digital power supply VCC output of the power supply circuit is connected to the digital power supply VCC input of the MCU control unit. The analog power supply Vdd output of the power supply circuit is connected to the analog power supply Vdd input of the MCU control unit. The power status signal DY output of the power supply circuit is connected to the power status signal DY input of the MCU control unit. The 2n isolated drive power supply V1 to V2n outputs of the power supply circuit are respectively connected to the isolated drive power supply V1 to V2n inputs of different MCU control units.

[0038] The power ground terminal GND of the MCU control unit is connected to the power ground terminal GND of the front isolation drive protection circuit Ui. The control signal Gi output terminal of the MCU control unit is connected to the control signal Gi input terminal of the front isolation drive protection circuit Ui. The overcurrent protection status signal Fi output terminal of the front isolation drive protection circuit Ui is connected to the overcurrent protection status signal Fi input terminal of the MCU control unit. The power ground terminal GNDi of the front isolation drive protection circuit Ui is connected to the emitter of the front switch control module Qi. The drive signal Qi-G output terminal of the front isolation drive protection circuit Ui is connected to the gate of the front switch control module Qi. The saturation voltage BVi sampling terminal of the front isolation drive protection circuit Ui is connected to the anode of the front isolation diode Di, and the cathode of the front isolation diode Di is connected to the collector of the front switch control module Qi.

[0039] The power ground terminal GND of the MCU control unit is connected to the power ground terminal GND of the rear isolation drive protection circuit U(i+n). The control signal output terminal G(i+n) of the MCU control unit is connected to the control signal input terminal G(i+n) of the rear isolation drive protection circuit U(i+n). The overcurrent protection status signal F(i+n) output terminal of the rear isolation drive protection circuit U(i+n) is connected to the overcurrent protection status signal F(i+n) input terminal of the MCU control unit. The power ground terminal GND(i+n) of the rear isolation drive protection circuit U(i+n) is connected to the emitter of the rear switch control module Q(i+n). The drive signal Q(i+n)-G output terminal of the rear isolation drive protection circuit U(i+n) is connected to the gate of the rear switch control module Q(i+n). The sampling terminal of the saturation voltage BV(i+n) of the rear isolation drive protection circuit U(i+n) is connected to the anode of the diode D(i+n), and the cathode of the rear isolation diode D(i+n) is connected to the collector of the rear switch control module Q(i+n).

[0040] The collector of the front switch control module Qi is connected to the positive terminal Ci+ of the bus of the i-th pitch driver and one end of the absorption capacitor Ci. The emitter of the front switch control module Qi is connected to the emitter of the rear switch control module Q(i+n). The collector of the rear switch control module Q(i+n) is connected to one end of the buffer capacitor C(i+n). The other end of the absorption capacitor Ci is connected to the other end of the buffer capacitor C(i+n).

[0041] The collector of the front switch control module Qi is connected to the positive voltage VCI input terminal of the pitch driver bus of the isolation voltage sampling circuit. The collector of the rear switch control module Q(i+n) is connected to the positive voltage HV+ input terminal of the common bus of the isolation voltage sampling circuit. The connection point of the buffer capacitor C(i+n) and the absorption capacitor Ci is connected to the negative voltage HV- input terminal of the common bus of the isolation voltage sampling circuit. The output terminal of the positive voltage VCI of the pitch driver bus of the isolation voltage sampling circuit is connected to the positive voltage VCI input terminal of the pitch driver bus of the MCU control unit. The output terminal of the positive voltage HV+ of the common bus of the isolation voltage sampling circuit is connected to the positive voltage HV+ input terminal of the common bus of the MCU control unit. The output terminal of the negative voltage HV- of the common bus of the isolation voltage sampling circuit is connected to the negative voltage HV- input terminal of the common bus of the MCU control unit.

[0042] In the MCU control unit, the control logic relationship of the control signal Gi of the front switch control module Qi corresponding to the i-th pitch driver is as follows:

[0043] Gi=DY&BHi&Fi&(ΔU1i≤ΔU1)&(ΔU2i≤ΔU2)&ENi

[0044] In the MCU control unit, the control logic relationship of the control signal G(i+n) of the rear switch control module Q(i+n) corresponding to the i-th pitch driver is as follows:

[0045] G(i+n)=DY&BHi&F(i+n)&(ΔU1i≤ΔU1)&(ΔU2i≤ΔU2)&ENi

[0046] Wherein, DY represents the power status signal; BHi represents the status signal of the i-th pitch driver; Fi represents the overcurrent protection status signal of the front isolation drive protection circuit Ui, and F(i+n) represents the overcurrent protection status signal of the rear isolation drive protection circuit U(i+n); ΔU1i represents the absolute value of the deviation between the positive voltage VCI of the i-th pitch driver bus and the average value U of the positive voltages VC1 to VCn of all pitch drivers, and ΔU1 represents the first absolute value threshold of the deviation; ΔU2i represents the absolute value of the deviation between the positive voltage VCI of the i-th pitch driver bus and the positive voltage HV+ of the common bus, and ΔU2 represents the second absolute value threshold of the deviation; ENi represents the enable command received by the communication terminal to turn on the corresponding switch control module of the i-th pitch driver (generally sent by the host computer); & represents AND logic.

[0047] When ENi is enabled, DY, BHi, and Fi or F(i+n) are all normal, and ΔVCi is normal (ΔU1i≤ΔU1 and ΔU2i≤ΔU2 are satisfied), then Gi and G(i+n) are allowed to control the front switch control module Qi and the rear switch control module Q(i+n) to conduct, and the i-th pitch drive shares a common bus; otherwise, Gi and G(i+n) control the front switch control module Qi and the rear switch control module Q(i+n) to turn off, and the i-th pitch drive is isolated from the common bus, such as... Figure 2 As shown.

[0048] Because the switching transistors that make up the switching control module turn off at a speed (usually less than 5 microseconds) much faster than mechanical switches such as contactors (usually tens to hundreds of milliseconds), this energy equalizer can quickly isolate faulty drives and ensure the safe and reliable operation of the pitch system.

[0049] The control method for the common bus energy equalizer of the above-mentioned multiple pitch servo drives includes the following steps:

[0050] 1) Control phase upon initial power-on.

[0051] After receiving the start command, the MCU control unit dynamically acquires the power status signal DY, the status signals BH1~BHn of all pitch drive units, and the status signals F1~F2n of all overcurrent protection units.

[0052] If the power status signal DY, all pitch drive status signals BH1~BHn, and all overcurrent protection status signals F1~F2n are normal, then obtain the positive voltages VC1~VCn of all pitch drive buses, calculate the average value U of the positive voltages VC1~VCn of all pitch drive buses, and then calculate the absolute value ΔU1i of the deviation between the positive voltage VCI of the i-th pitch drive bus and the average value U:

[0053] If the absolute values ​​of the deviations ΔU11 to ΔU1n are all not greater than (less than or equal to) the set first absolute value threshold ΔU1 (ΔU1 is set according to the parameters of the switching transistor group and the buffer capacitor to allow the voltage difference to be set so as not to damage the device during the initial connection), then the MCU control unit sends control signals G1 to G2n to the front isolation drive protection circuits U1 to Un and the rear isolation drive protection circuits Un+1 to U2n. The front isolation drive protection circuits U1 to Un and the rear isolation drive protection circuits Un+1 to U2n send drive signals Q1-G to Q2n-G to drive the front switch control modules Q1 to Qn and the rear switch control modules Qn+1 to Q2n to turn on.

[0054] Otherwise, the MCU control unit sends control signals G1~G2n to the front isolation drive protection circuits U1~Un and the rear isolation drive protection circuits Un+1~U2n. The front isolation drive protection circuits U1~Un and the rear isolation drive protection circuits Un+1~U2n send drive signals Q1-G~Q2n-G to drive the front switch control modules Q1~Qn and the rear switch control modules Qn+1~Q2n to turn off.

[0055] Otherwise, the MCU control unit sends control signals G1~G2n to the front isolation drive protection circuits U1~Un and the rear isolation drive protection circuits Un+1~U2n. The front isolation drive protection circuits U1~Un and the rear isolation drive protection circuits Un+1~U2n send drive signals Q1-G~Q2n-G to drive the front switch control modules Q1~Qn and the rear switch control modules Qn+1~Q2n to turn off.

[0056] 2) Common bus adaptive equalization energy distribution control stage.

[0057] When the front switch control module Qi and the rear switch control module Q(i+n) corresponding to the i-th pitch drive are initially turned on, the positive terminal Ci+ of the i-th pitch drive bus charges the buffer capacitor C(i+n) through the front switch transistor of the front switch control module Qi and the rear switch transistor of the rear switch control module Q(i+n) until the voltage across the buffer capacitor C(i+n) reaches the common bus quasi-stable value Ucom. Because the gate drive signal Qi-G of the front switch transistor of the front switch control module Qi and the gate drive signal Q(i+n)-G of the rear switch transistor of the rear switch control module Q(i+n) are both effectively turned on by the isolation drive protection circuit, whether the front switch transistor of the front switch control module Qi and the rear switch transistor of the rear switch control module Q(i+n) are turned on depends on the voltage difference between the collector and emitter of the switch transistor. Therefore, during operation, the positive terminal voltage VCI of each pitch drive bus will fluctuate with its own operating conditions, and the common bus quasi-stable value Ucom will also change accordingly.

[0058] When the positive voltage VCi of the i-th pitch driver bus is greater than (the common bus quasi-stable value Ucom + the voltage drop of the front switch transistor of the front switch control module Qi + the voltage drop of the freewheeling diode of the rear switch control module Q(i+n)), the freewheeling diode of the corresponding front switch control module Qi and the rear switch transistor of the rear switch control module Q(i+n) are turned off, while the front switch transistor of the switch control module Qi and the freewheeling diode of the rear switch control module Q(i+n) are turned on. The positive terminal Ci+ of the i-th pitch driver bus charges the buffer capacitor C(i+n) through the front switch transistor of the switch control module Qi and the freewheeling diode of the rear switch control module Q(i+n). The magnitude of the charging current is determined by the difference between the positive voltage VCi of the i-th pitch driver bus and the common bus quasi-stable value Ucom, as well as the equivalent resistance of the switch transistor of the front switch control module Qi and the freewheeling diode of the rear switch control module Q(i+n).

[0059] When (common bus metastable value Ucom - voltage drop of the rear switch transistor of the rear switch control module Q(i+n) - voltage drop of the freewheeling diode of the front switch control module Qi) ≤ the positive voltage VCi of the i-th pitch driver bus ≤ (common bus metastable value Ucom + voltage drop of the front switch transistor of the front switch control module Qi + voltage drop of the freewheeling diode of the rear switch control module Q(i+n)), the front switch transistor and freewheeling diode of the corresponding front switch control module Qi, and the rear switch transistor Q(i+n) and freewheeling diode of the rear switch control module Q(i+n) are all cut off, and the positive terminal Ci+ of the i-th pitch driver bus is neither charged nor discharged.

[0060] When the positive voltage VCi of the i-th pitch driver bus is less than (common bus quasi-stable value Ucom - voltage drop across the rear switch transistor of the rear switch control module Q(i+n) - voltage drop across the freewheeling diode of the front switch control module Qi), the front switch transistor of the corresponding front switch control module Qi and the freewheeling diode of the rear switch control module Q(i+n) are cut off, while the freewheeling diode of the front switch control module Qi and the rear switch transistor of the rear switch control module Q(i+n) are turned on. The buffer capacitor C(i+n) discharges to the positive terminal Ci+ of the i-th pitch driver bus through the rear switch transistor of the rear switch control module Q(i+n) and the freewheeling diode of the front switch control module Qi. The magnitude of the discharge current is determined by the difference between the positive voltage VCi of the i-th pitch driver bus and the common bus quasi-stable value Ucom, as well as the equivalent resistance of the switch transistor Q(i+n) of the rear switch control module and the freewheeling diode of the front switch control module Qi.

[0061] This energy equalizer, through the aforementioned energy distribution control, adaptively and evenly adjusts the direction and magnitude of electrical energy flow to each pitch driver bus that shares a common bus, based on the relationship between the pitch driver bus voltage VCI, the common bus voltage Ucom, the on-state voltage drop of the switching transistor and the freewheeling diode, and their equivalent resistance.

[0062] 3) Common busbar operation control stage.

[0063] The MCU control unit acquires the power status signal DY. When the power status signal DY is abnormal, the MCU control unit sends control signals G1~G2n to the front isolation drive protection circuits Un+1~U2n and the rear isolation drive protection circuits Un+1~U2n. The front isolation drive protection circuits Un+1~U2n and the rear isolation drive protection circuits Un+1~U2n then send drive signals Q1-G~Q2n-G to turn off the front switch control modules Q1~Qn and the rear switch control modules Qn+1~Q2n. Otherwise, proceed to the next step.

[0064] The MCU control unit acquires the status signal BHi of the i-th pitch driver. When the status signal BHi of the i-th pitch driver is abnormal, the MCU control unit sends control signals Gi and G(i+n) to the front isolation drive protection circuit Ui and the rear isolation drive protection circuit U(i+n). The front isolation drive protection circuit Ui and the rear isolation drive protection circuit U(i+n) then send drive signals Qi-G and Q(i+n)-G to turn off the front switch control module Qi and the rear switch control module Q(i+n). Otherwise, proceed to the next step.

[0065] The MCU control unit acquires the overcurrent protection status signals Fi and F(i+n) of the i-th pitch driver. When the overcurrent protection status signals Fi and F(i+n) of the i-th pitch driver are abnormal, the MCU control unit sends control signals Gi and G(i+n) to the front isolation drive protection circuit Ui and the rear isolation drive protection circuit U(i+n). The front isolation drive protection circuit Ui and the rear isolation drive protection circuit U(i+n) then send drive signals Qi-G and Q(i+n)-G to turn off the front switch control module Qi and the rear switch control module Q(i+n). Otherwise, proceed to the next step.

[0066] The MCU control unit acquires the positive voltage VCI of the i-th pitch driver bus and the positive voltage HV+ of the common bus. If the absolute value of the deviation between the positive voltage VCI of the i-th pitch driver bus and the positive voltage HV+ of the common bus is greater than a set second absolute deviation threshold, the MCU control unit sends control signals Gi and G(i+n) to the front isolation drive protection circuit Ui and the rear isolation drive protection circuit U(i+n). The front isolation drive protection circuit Ui and the rear isolation drive protection circuit U(i+n) then send drive signals Qi-G and Q(i+n)-G to turn off the front switch control module Qi and the rear switch control module Q(i+n). Otherwise, proceed to the next step.

[0067] The MCU control unit reads and executes instructions from the communication terminal.

[0068] In the above, i = 1, 2, ..., n, where n is the number of pitch drives.

[0069] It should be noted that although the embodiments described above are illustrative, they are not intended to limit the present invention. Therefore, the present invention is not limited to the specific embodiments described above. Any other embodiments obtained by those skilled in the art under the guidance of the present invention without departing from its principles are considered to be within the protection scope of the present invention.

Claims

1. A common bus energy equalizer for multiple pitch servo drives, characterized in that, It consists of n sets of isolated drive protection circuits, n sets of switch control modules, n sets of isolation diodes, n sets of capacitors, n rectifier diodes, isolated voltage sampling lines, power supply circuits and MCU control units; The i-th isolation drive protection circuit group corresponds to the i-th pitch driver, including one front isolation drive protection circuit Ui and one rear isolation drive protection circuit U(i+n); the i-th switch control module group corresponds to the i-th pitch driver, including a front switch control module Qi and a rear switch control module Q(i+n); the i-th isolation diode group corresponds to the i-th pitch driver, including a front isolation diode Di and a rear isolation diode D(i+n); the i-th capacitor group corresponds to the i-th pitch driver, including an absorption capacitor Ci and a buffer capacitor C(i+n); the i-th rectifier diode DXi corresponds to the i-th pitch driver. Each front switch control module Qi includes a front switch transistor and a front freewheeling diode. The gate of the front switch transistor forms the gate of the front switch control module Qi. The anode of the front freewheeling diode is connected to the emitter of the front switch transistor to form the emitter of the front switch control module Qi. The cathode of the front freewheeling diode is connected to the collector of the front switch transistor to form the collector of the front switch control module Qi. Each post-switch control module Q(i+n) includes a post-switch transistor and a post-current diode. The gate of the post-switch transistor forms the gate of the post-switch control module Q(i+n). The anode of the post-current diode is connected to the emitter of the post-switch transistor to form the emitter of the post-switch control module Q(i+n). The cathode of the post-current diode is connected to the collector of the post-switch transistor to form the collector of the post-switch control module Q(i+n). The positive terminal Ci+ of the i-th pitch driver bus is connected to the collector of the front switch control module Qi; the negative terminal Ci- of the i-th pitch driver bus is connected to the connection point of the buffer capacitor C(i+n) and the absorption capacitor Ci; the pitch driver status signal BHi output terminal of the i-th pitch driver is connected to the different pitch driver status signal BHi input terminals of the MCU control unit; the communication terminals of all pitch drivers are connected to the communication terminal of the MCU control unit. The positive terminal Ci+ of the i-th pitch driver bus is connected to the anode of the rectifier diode DXi, and the cathode of the rectifier diode DXi is connected to the positive terminal CV+ of the pitch driver bus of the power supply circuit; the negative terminal Ci- of the i-th pitch driver bus is connected to the negative terminal CV- of the pitch driver bus of the power supply circuit; the digital power supply VCC output terminal of the power supply circuit is connected to the digital power supply VCC input terminal of the MCU control unit; the analog power supply Vdd output terminal of the power supply circuit is connected to the analog power supply Vdd input terminal of the MCU control unit; the power status signal DY output terminal of the power supply circuit is connected to the power status signal DY input terminal of the MCU control unit; the 2n isolated drive power supply V1~V2n output terminals of the power supply circuit are respectively connected to the isolated drive power supply V1~V2n input terminals of different MCU control units; The power ground terminal GND of the MCU control unit is connected to the power ground terminal GND of the front isolation drive protection circuit Ui; the control signal Gi output terminal of the MCU control unit is connected to the control signal Gi input terminal of the front isolation drive protection circuit Ui; the overcurrent protection status signal Fi output terminal of the front isolation drive protection circuit Ui is connected to the overcurrent protection status signal Fi input terminal of the MCU control unit; the power ground terminal GNDi of the front isolation drive protection circuit Ui is connected to the emitter of the front switch control module Qi; the drive signal Qi-G output terminal of the front isolation drive protection circuit Ui is connected to the gate of the front switch control module Qi; the saturation voltage BVi sampling terminal of the front isolation drive protection circuit Ui is connected to the anode of the front isolation diode Di, and the cathode of the front isolation diode Di is connected to the collector of the front switch control module Qi; The power ground terminal GND of the MCU control unit is connected to the power ground terminal GND of the rear isolation drive protection circuit U(i+n); the control signal output terminal G(i+n) of the MCU control unit is connected to the control signal input terminal G(i+n) of the rear isolation drive protection circuit U(i+n); The overcurrent protection status signal F(i+n) output terminal of the rear isolation drive protection circuit U(i+n) is connected to the overcurrent protection status signal F(i+n) input terminal of the MCU control unit; the power ground terminal GND(i+n) of the rear isolation drive protection circuit U(i+n) is connected to the emitter of the rear switch control module Q(i+n); The output terminal of the drive signal Q(i+n)-G of the rear isolation drive protection circuit U(i+n) is connected to the gate of the rear switch control module Q(i+n); the sampling terminal of the saturation voltage BV(i+n) of the rear isolation drive protection circuit U(i+n) is connected to the anode of the diode D(i+n), and the cathode of the rear isolation diode D(i+n) is connected to the collector of the rear switch control module Q(i+n); The collector of the front switch control module Qi is connected to the positive terminal Ci+ of the bus of the i-th pitch driver and one end of the absorption capacitor Ci. The emitter of the front switch control module Qi is connected to the emitter of the rear switch control module Q(i+n). The collector of the rear switch control module Q(i+n) is connected to one end of the buffer capacitor C(i+n). The other end of the absorption capacitor Ci is connected to the other end of the buffer capacitor C(i+n). The collector of the front switch control module Qi is connected to the positive voltage VCI input terminal of the i-th pitch driver bus of the isolation voltage sampling line; the collector of the rear switch control module Q(i+n) is connected to the positive voltage HV+ input terminal of the common bus of the isolation voltage sampling line; the connection point of the buffer capacitor C(i+n) and the absorption capacitor Ci is connected to the negative voltage HV- input terminal of the common bus of the isolation voltage sampling line; the output terminal of the positive voltage VCI of the i-th pitch driver bus of the isolation voltage sampling line is connected to the positive voltage input terminal VCI of the pitch driver bus of the MCU control unit; the output terminal of the positive voltage HV+ of the common bus of the isolation voltage sampling line is connected to the positive voltage HV+ input terminal of the common bus of the MCU control unit; the output terminal of the negative voltage HV- of the common bus of the isolation voltage sampling line is connected to the negative voltage HV- input terminal of the common bus of the MCU control unit. In the above, i = 1, 2, ..., n, where n is the number of pitch drives.

2. The energy equalizer for multiple pitch servo drives according to claim 1, characterized in that, The front switching transistor of the front switching control module Qi and the rear switching transistor of the rear switching control module Q(i+n) in each group of switching control modules have the same specifications; the front freewheeling diode of the front switching control module Qi and the rear freewheeling diode of the rear switching control module Q(i+n) in each group of switching control modules have the same specifications.

3. The energy equalizer for multiple pitch servo drives according to claim 1, characterized in that, All front isolation drive protection circuits and all rear isolation drive protection circuits include the ACPL-332J switching transistor driver chip.

4. The energy equalizer for multiple pitch servo drives according to claim 1, characterized in that, The communication terminal of the MCU control unit is also connected to the host computer.

5. The energy equalizer for multiple pitch servo drives according to claim 1, characterized in that, In the MCU control unit, the control logic relationship of the control signal Gi of the front switch control module Qi corresponding to the i-th pitch driver is as follows: Gi=DY&BHi&Fi&(ΔU1i≤ΔU1)&(ΔU2i≤ΔU2)&ENi In the MCU control unit, the control logic relationship of the control signal G(i+n) of the rear switch control module Q(i+n) corresponding to the i-th pitch driver is as follows: G(i+n)=DY&BHi&F(i+n)&(ΔU1i≤ΔU1)&(ΔU2i≤ΔU2)&ENi Wherein, DY represents the power status signal; BHi represents the status signal of the i-th pitch driver; Fi represents the overcurrent protection status signal of the front isolation drive protection circuit Ui, and F(i+n) represents the overcurrent protection status signal of the rear isolation drive protection circuit U(i+n); ΔU1i represents the absolute value of the deviation between the positive voltage VCI of the i-th pitch driver bus and the average value U of the positive voltages VC1 to VCn of all pitch drivers, and ΔU1 represents the first absolute value threshold of the deviation; ΔU2i represents the absolute value of the deviation between the positive voltage VCI of the i-th pitch driver bus and the positive voltage HV+ of the common bus, and ΔU2 represents the second absolute value threshold of the deviation; ENi represents the enable command received by the communication terminal to turn on the corresponding switch control module of the i-th pitch driver; & represents AND logic.

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