WO2019218796A1

WO2019218796A1 - Capacity control system and method for screw compressor capable of switching running rotating speed at constant frequency

Info

Publication number: WO2019218796A1
Application number: PCT/CN2019/081436
Authority: WO
Inventors: 森山昌幸; 徐峰; 张林波; 朱应求
Original assignee: 麦克维尔空调制冷(武汉)有限公司
Priority date: 2018-05-18
Filing date: 2019-04-04
Publication date: 2019-11-21
Also published as: CN108468643A

Abstract

A capacity control system and method for a screw compressor capable of switching a running rotating speed at a constant frequency, comprising a screw compressor (1) having a constant-frequency motor. The screw compressor (1) is provided with a bypass slide valve (8) having an adjustable capacity, and is also provided with a bypass slide valve action driver (4), a motor driver (5), a system controller (7), and a load measuring device (6); the bypass slide valve (8) is in a signal connection to the bypass slide valve action driver (4) and is controlled by the bypass slide valve action driver (4); a bypass slide valve position sensor (9) is further provided, and the bypass slide valve position sensor (9) is connected to the screw compressor (1) for measuring the position of the slide valve (8); the load measuring device (6) is configured to detect the running load state of the compressor (1); the motor driver (5) is connected to the constant-frequency compressor (1); the bypass slide valve position sensor (9), the bypass slide valve action driver (4), the load measuring device (6), and the motor driver (5) are in a signal connection to the system controller (7). The control system and method can realize a high coefficient of performance (COP) of the compressor in full-load running and partial-load running, adapt to frequent starting sites, and inhibit starting a current peak value.

Description

可定频切换转速运行的螺杆压缩机容量控制***及方法Screw compressor capacity control system and method capable of operating at constant frequency switching speed

技术领域Technical field

本发明属于制冷空调动力控制技术领域，具体涉及一种螺杆压缩机容量控制***及方法。The invention belongs to the technical field of refrigeration air conditioning power control, and particularly relates to a screw compressor capacity control system and method.

背景技术Background technique

螺杆式制冷空调机组，一般分为使用定频定速驱动螺杆压缩机的空调机组(简称定频螺杆机组)，和使用变频变速驱动螺杆压缩机的空调机组(简称变频螺杆机组)。定频螺杆机组满负荷性能系数高，但减载至部分负荷运行时性能较低；变频螺杆机组部分负荷运行时性能高，但满负荷性能系数下降，但相比定频螺杆机组成本高价格贵。The screw type refrigeration air conditioning unit is generally divided into an air conditioning unit (referred to as a fixed frequency screw unit) using a fixed frequency fixed speed driving screw compressor, and an air conditioning unit (referred to as a variable frequency screw unit) using a variable frequency variable speed driving screw compressor. The fixed-frequency screw unit has a high full-load performance coefficient, but the performance is low when the load is reduced to partial load operation; the performance of the variable-frequency screw unit during partial load operation is high, but the full-load performance coefficient decreases, but the cost is higher than that of the fixed-frequency screw unit. .

使用定频定速螺杆压缩机的定频螺杆机组，其在负荷降低由满负荷减载至部分负荷运行时，其定频螺杆压缩机一般通过滑阀等旁通装置进行容量调节，由于针对旁通卸载的气体在旁通之前已经过压缩，存在无效做功，其部分负荷性能系数COP较低。A fixed-frequency screw unit using a fixed-frequency fixed-speed screw compressor, when the load is reduced from full load to partial load operation, the fixed-frequency screw compressor is generally adjusted by a bypass device such as a slide valve, The unloaded gas has been compressed before bypassing, and there is invalid work, and its partial load performance coefficient COP is low.

使用变频变速螺杆压缩机的变频螺杆机组，其在负荷降低由满载减载至部分负荷时，通过变频器调节螺杆压缩机转速来实现容量调节，不存在旁通引起的无效做功，其部分负荷性能系数较高，由于变频器存在功率损耗(约3～5％)，满负荷运行时，其性能系数COP相比定频螺杆空调机组有3～5％左右下降，但变频器成本高导致变频螺杆机组整机成本高。The frequency conversion screw unit using the variable frequency variable speed screw compressor realizes the capacity adjustment by adjusting the screw compressor speed through the frequency converter when the load is reduced from full load to partial load, and there is no ineffective work caused by bypass, and its partial load performance The coefficient is higher, due to the power loss of the inverter (about 3 to 5%), the performance coefficient COP is about 3 to 5% lower than that of the fixed-frequency screw air conditioning unit at full load operation, but the inverter cost is high, resulting in the frequency conversion screw. The overall cost of the unit is high.

因而将定频螺杆机组进行合适速度控制，特别是在与定频定速螺杆机组相当的成本下实现满负荷和部分负荷运行时性能系数COP均为较高的螺杆式制冷空调机组，将成为目前制冷技术领域的一个亟待解决的技术问题。Therefore, the fixed-speed screw unit is equipped with suitable speed control, especially at the cost equivalent to the fixed-frequency fixed-speed screw unit, the screw-type refrigeration air-conditioning unit with high performance coefficient COP at full load and partial load operation will become the current An urgent technical problem in the field of refrigeration technology.

工业应用中，时常需要一个电机可以双速(多速)运行，双速(多速)均指速度变换档位如高速、低速或中速的区分。常用的双速(多速)电机启动及运行手段有接触器驱动，变频器驱动，软启动器驱动。而接触器驱动实现电机星三角启动及高低速切换这种方案启动过程中有二次电流冲击，成本高，结构复杂，故障率高；而变频器驱动实现电机启动及高低速切换这种方案启动过程中虽然无二次电流冲击，且启动电流小，启动平滑，但该方案成本太高；软启动器驱动实现电机软启动及高低速切换这个方案，以成本低，结构简单，启动无冲击而得到广泛应用。In industrial applications, it is often required that one motor can operate at two speeds (multi-speed), and two-speed (multi-speed) refers to the distinction of speed change gears such as high speed, low speed or medium speed. Commonly used two-speed (multi-speed) motor starting and running means are contactor drive, inverter drive, soft starter drive. The contactor drive realizes the motor star-delta start and high-low-speed switching. The scheme has secondary current surge during the startup process, high cost, complicated structure and high failure rate. The inverter drive realizes motor start and high and low speed switching. Although there is no secondary current impact in the process, and the starting current is small, the starting is smooth, but the cost of the solution is too high; the soft starter drive realizes the soft start of the motor and the high and low speed switching, which has low cost, simple structure and no impact at startup. Widely used.

传统的软启动器驱动方案一般是使用一个软启动器，再配置两个(多个)接触器，启动时，先闭合一个接触器，再启动软启动器，停止时先停软启动器再释放接触器。由于软启动器对单位小时内的启动次数有要求，如果现场要求启动次数频繁该方案可能会造成软启动器损坏，软启动器驱动高速时电流要求大，驱动低速时要求电流小，启动参数和启动限流都不同，保护参数也不同，因此，传统的软启动器驱动方案无法可靠的保护电机，并控制启动曲线。The traditional soft starter drive scheme generally uses a soft starter and then configures two (multiple) contactors. When starting, first close a contactor, then start the soft starter, stop the soft starter and then release. Contactor. Since the soft starter has requirements for the number of starts per unit hour, if the number of starts required on the site is frequent, the scheme may cause damage to the soft starter. When the soft starter drives high speed, the current demand is large, when the drive is low, the current is required to be small, and the startup parameters are The starting current limit is different and the protection parameters are different. Therefore, the traditional soft starter driving scheme cannot reliably protect the motor and control the starting curve.

发明内容Summary of the invention

本发明所要解决的技术问题是提供一种可定频切换转速运行的螺杆压缩机容量控制***及方法，在与定频定速螺杆机组相当的成本下实现较高的满负荷和部分负荷运行时性能系数COP，并能适应启动频繁的现场，具备抑制启动电流峰值的能力。The technical problem to be solved by the present invention is to provide a screw compressor capacity control system and method capable of operating at a fixed frequency switching speed, achieving high full load and partial load operation at a cost equivalent to a fixed frequency fixed speed screw unit. The coefficient of performance is COP, and it can adapt to the scene with frequent start-up and has the ability to suppress the peak value of the starting current.

本发明供针对需要解决的技术问题，提供了如下解决的技术方案：The present invention provides a technical solution for solving the technical problem to be solved as follows:

一种可定频切换转速运行的螺杆压缩机容量控制***，包括含定频电机的螺杆压缩机，螺杆压缩机上安装有可调节容量的旁通滑阀，还设置旁通滑阀动作驱动器、电机驱动器、控制器以及负荷测量装置，旁通滑阀与旁通滑阀动作驱动器信号连接、并受旁通滑阀动作驱动器控制，其特征在于：还设置旁通滑阀位置传感器，旁通滑阀位置传感器与螺杆压缩机连接用于测量滑阀位置，负荷测量装置用于检测压缩机运行负荷需求，电机驱动器与定频压缩机连接；旁通滑阀位置传感器、旁通滑阀动作驱动器、负荷测量装置、电机驱动器与控制器信号连接。A screw compressor capacity control system capable of operating at a fixed frequency switching speed, comprising a screw compressor with a fixed frequency motor, a bypass spool valve with adjustable capacity installed on the screw compressor, and a bypass slide valve action driver and motor The drive, the controller and the load measuring device, the bypass slide valve is connected with the bypass spool action driver signal, and is controlled by the bypass spool action driver, and is characterized in that a bypass slide valve position sensor and a bypass slide valve are also provided. The position sensor is connected to the screw compressor for measuring the position of the spool, the load measuring device is used to detect the load demand of the compressor, the motor driver is connected with the fixed frequency compressor, the position sensor of the bypass valve, the action driver of the bypass spool, and the load The measuring device, the motor driver and the controller signal are connected.

进一步的，所述电机驱动器设置为可实现定频电机速度双速或多速运行以及在速度档位间进行切换。Further, the motor driver is configured to achieve a two-speed or multi-speed operation of the fixed-frequency motor speed and to switch between speed gears.

进一步的，定频电机包括至少一个绕组，通过接线方式切换绕组的极数和转速；电机驱动器包括至少一个软启动器和和两个/多个接触器；软启动器通过两个/多个接触器选择性连接电机绕组。Further, the fixed frequency motor includes at least one winding that switches the number of poles and the rotational speed of the winding by way of wiring; the motor driver includes at least one soft starter and two or more contactors; and the soft starter passes two or more contacts The motor is selectively connected to the motor windings.

进一步的，定频电机包括至少一组高速绕组和至少一组低速绕组；相对应的，电机驱动器包括一个高速软启动器和一个低速软启动器，和至少一个断路器；断路器与低速软启动器和高速软启动器分别连接；高速软启动器与定频电机的高速绕组连接；低速软启动器与定频电机的低速绕组连接。Further, the fixed frequency motor includes at least one set of high speed windings and at least one set of low speed windings; correspondingly, the motor drive includes a high speed soft starter and a low speed soft starter, and at least one circuit breaker; the circuit breaker and the low speed soft start The high speed soft starter is connected to the high speed soft starter; the high speed soft starter is connected to the high speed winding of the fixed frequency motor; and the low speed soft starter is connected to the low speed winding of the fixed frequency motor.

进一步的，当定频压缩机中还包括至少一组转速位于高速绕组和低速绕组之间的中速绕组时，所述软启动器电控柜中还设置若干启动接触器；其中高速软启动器的输出端通过一个启动接触器与定频压缩机的高速绕组连接；低速软启动器的输出端上设置若干并列的启动接触器，该若干并列的启动接触器均按一一对接的方式连接低速绕组和各中速绕组。Further, when the fixed frequency compressor further includes at least one set of medium speed windings between the high speed winding and the low speed winding, the soft starter electric control cabinet is further provided with a plurality of starting contactors; wherein the high speed soft starter The output end is connected to the high speed winding of the fixed frequency compressor through a starting contactor; the side of the low speed soft starter is provided with a plurality of parallel starting contactors, and the plurality of parallel starting contactors are connected at a low speed in a one-to-one connection manner. Winding and each medium speed winding.

进一步的，在高速软启动器和一个低速软启动器前方各设置一个断路器；两个断路器并联在电源上。Further, a circuit breaker is disposed in front of the high speed soft starter and a low speed soft starter; the two circuit breakers are connected in parallel to the power supply.

进一步的，两个断路器的前方主路上连接一个隔离开关QS；通过隔离开关QS构成两个断路器可选择地与各自软启动器连接。Further, an isolation switch QS is connected to the front main road of the two circuit breakers; two circuit breakers are formed by the isolating switch QS to be selectively connected to the respective soft starters.

采用上述可定频切换转速运行的螺杆压缩机控制方法，其特征在于：在电机处于不同转速运行时，控制器根据负荷测量装置获取负荷需求，旁通滑阀位置传感器检测滑阀开度位置信号，控制器根据负荷需求及滑阀位置信号，通过电机驱动器来调节电机运行转速实现多速输出和/或切换，并通过旁通滑阀动作驱动器调节旁通滑阀开度位置，使旁通滑阀开度位置处于设定的开度范围，所述开度范围使滑阀开度位置始终与电机速度保持着向电机低速运转和滑阀位高开度位置的趋势运行。The screw compressor control method using the above-mentioned fixed-frequency switching speed operation is characterized in that: when the motor is running at different speeds, the controller acquires the load demand according to the load measuring device, and the bypass spool position sensor detects the position signal of the spool opening position. According to the load demand and the position signal of the spool valve, the controller adjusts the running speed of the motor through the motor driver to realize multi-speed output and/or switching, and adjusts the opening position of the bypass spool by the bypass spool action driver to make the bypass slide The valve opening position is within a set opening range that keeps the spool opening position always in line with the motor speed maintaining a tendency toward low speed operation of the motor and a high opening position of the spool position.

进一步的，通过电机驱动器来调节电机运行转速实现三速输出和/或切换具体流程如下：Further, the specific process of adjusting the running speed of the motor through the motor driver to achieve the three-speed output and/or switching is as follows:

定频压缩机高速运行时，检测滑阀开度位置，如滑阀开度位置≤H％且有减载需求时，定频压缩机切入中速运行，否则继续在高速运行状态下运行；H％为在控制器中设定的压缩机高速运行时滑阀开度位置下限；When the fixed-frequency compressor runs at high speed, the position of the spool opening is detected. If the position of the spool opening is ≤H% and there is demand for load shedding, the fixed-frequency compressor cuts into the medium-speed operation, otherwise it continues to run at high-speed operation; % is the lower limit of the spool opening position when the compressor is set to operate at high speed in the controller;

中速运行时，检测滑阀开度位置，如滑阀开度位置≤M％且有减载需求时，定频压缩机切入低速运行；如滑阀位在100％且有增载需求时，定频压缩机切入高速运行，使滑阀开度位置在H％～100％；否则继续在中速运行状态下运行，保持中速运行的滑阀开度位置为M％～100％；其中，M％为压缩机中速运行时滑阀开度位置下限；During medium speed operation, the position of the slide valve opening is detected. If the position of the valve opening is ≤ M% and there is demand for load shedding, the fixed frequency compressor cuts into low speed operation; if the spool position is 100% and there is demand for load increase, The fixed-frequency compressor cuts into high-speed operation, so that the position of the spool opening is in the range of H% to 100%; otherwise, it continues to operate in the medium-speed operation state, and the position of the spool opening of the medium-speed operation is M% to 100%; M% is the lower limit of the spool opening position when the compressor is running at medium speed;

低速运行时，检测滑阀开度位置，如滑阀位在100％且有增载需求，则切换到中速运行，保持中速运行的滑阀开度位置为M％～100％；否则继续保持低速运行，保持低速运行的滑阀开度位置为N％～100％；其中，N％为压缩机低速运行时滑阀开度位置下限。When running at low speed, check the position of the slide valve opening. If the spool position is at 100% and there is load increase demand, switch to medium speed operation, and keep the position of the spool opening of medium speed operation from M% to 100%; otherwise continue Maintaining low speed operation, the position of the spool opening of the low speed operation is N% to 100%; wherein, N% is the lower limit of the position of the spool opening when the compressor is running at low speed.

进一步的，通过电机驱动器来调节电机运行转速实现双速输出和/或切换具体流程如下：Further, the specific process of adjusting the running speed of the motor through the motor driver to achieve two-speed output and/or switching is as follows:

控制器设定旁通滑阀的滑阀开度位置下限为H％；即滑阀开度位置范围为H％～100％,对应压缩机输出容量范围50％～100％，在高转速下，当滑阀开度位置移动到H％，而螺杆压缩机容量还需进一步调小时，螺杆压缩机将切换至低转速运行，低转速运行时滑阀开度位置范围为0～100％,对应压缩机输出容量范围：最小负荷～50％。The controller sets the lower limit of the spool opening position of the bypass spool to be H%; that is, the spool opening position ranges from H% to 100%, corresponding to the compressor output capacity range of 50% to 100%, at high rotation speed, When the spool opening position moves to H%, and the screw compressor capacity needs to be further adjusted, the screw compressor will switch to low speed operation, and the spool opening position range is 0-100% at low speed operation, corresponding to compression. Machine output capacity range: minimum load ~ 50%.

进一步的，电机驱动器电源启动主回路配置两个软启动器时，高速软启动器控制电机的高速绕组，低速软启动器控制电机的低速绕组；高速软启动器和低速软启动器之间输出互锁，共同分担电机的运行、启动；***控制器根据负荷测量装置的输入信号及滑阀位置信号，通过旁通滑阀动作驱动器调节旁通滑阀位置，及通过电机驱动器来调节电机运行转速；电机不同转速运行时，旁通滑阀开度位置根据设定范围调整。Further, when the motor driver power supply starts the main circuit and configures two soft starters, the high speed soft starter controls the high speed winding of the motor, the low speed soft starter controls the low speed winding of the motor; and the output between the high speed soft starter and the low speed soft starter The lock shares the operation and start of the motor; the system controller adjusts the position of the bypass slide valve by the bypass slide valve action driver according to the input signal of the load measuring device and the position signal of the spool valve, and adjusts the running speed of the motor through the motor driver; When the motor is running at different speeds, the position of the bypass spool opening is adjusted according to the setting range.

进一步的，高速软启动器的电流上限由最高绕组的转速N0决定，低速软启动器的电流上限为中间转速绕组的转速N1决定，绕组匹配规则对应为：最高绕组的转速N0≥绕组转速＞中间转速绕组的转速N1，均由高速软启动驱动；绕组转速≤中间转速绕组的转速N1；都由低速软启动器驱动。Further, the upper limit of the current of the high-speed soft starter is determined by the rotation speed N0 of the highest winding, and the upper limit of the current of the low-speed soft starter is determined by the rotation speed N1 of the intermediate rotation winding, and the winding matching rule corresponds to: the rotation speed of the highest winding N0 ≥ winding rotation speed > middle The speed N1 of the speed winding is driven by a high speed soft start; the winding speed ≤ the speed N1 of the intermediate speed winding; both are driven by a low speed soft starter.

进一步的，电机启动方式为软启动，启动模式为斜坡电流模式，对电机启动电流峰值限流，调节启动电压，电流平滑上升使电机转速达到额定转速完成电机启动，电机的高速绕组对应一个高速软启动器，保护参数按高速电流保护限制，启动电流也按照高速电流限制，保证启动电流平滑；电机的低速绕组对应低速软启动器，保护参数按低速电流保护，启动电流也按照低速电流限制，保证启动电流平滑。Further, the motor starting mode is soft start, the starting mode is ramp current mode, the motor starting current peak current limit, the starting voltage is adjusted, the current is smoothly increased, the motor speed reaches the rated speed to complete the motor starting, and the high speed winding of the motor corresponds to a high speed soft. Starter, protection parameters are limited by high-speed current protection, starting current is also in accordance with high-speed current limit, ensuring smooth starting current; low-speed winding of motor corresponds to low-speed soft starter, protection parameter is protected by low-speed current, and starting current is also limited according to low-speed current. Start current smoothing.

进一步的，电机速度切换方式为：当高速切低速或中速时，先高速软启动器停止输出，电机自由停车数秒之后，启动低速软启动器，启动电机使电机运行在低速或中速；当中速切低速时，先低速软启动器停止输出，电机自由停车数秒之后，电机绕组从中速绕组切换到低速绕组，然后再次启动低速软启动器，启动电机使电机运行在低速；当低速切高速时，先低速软启动器停止输出，电机自由停车数秒之后，启动高速软启动器，启动电机使电机运行在高速。Further, the motor speed switching mode is: when the high speed cuts the low speed or the medium speed, the high speed soft starter stops outputting, and after the motor is freely stopped for a few seconds, the low speed soft starter is started, and the motor is started to make the motor run at low speed or medium speed; When the speed is low, the low-speed soft starter stops outputting. After the motor is free to stop for a few seconds, the motor winding is switched from the medium-speed winding to the low-speed winding, and then the low-speed soft starter is started again, the motor is started to make the motor run at low speed; The low-speed soft starter stops outputting, and after the motor is free to stop for a few seconds, the high-speed soft starter is started, and the motor is started to make the motor run at high speed.

本发明的有益效果是：The beneficial effects of the invention are:

1、使用定频双速或多速驱动的定频螺杆压缩机，旁通滑阀、滑阀位置传感器，主控制器，使压缩机不同转速运行时，滑阀控制在合理的行程范围内，达到满载和部分负荷高效率运行；1. Fixed-frequency screw compressor with fixed-frequency two-speed or multi-speed drive, bypass slide valve, slide valve position sensor, main controller, when the compressor is running at different speeds, the slide valve is controlled within a reasonable stroke range. High efficiency operation at full load and partial load;

2、用于定频螺杆空调机组时，不需要配置变频柜，在相同满负荷COP和部分负荷COP相当的前提下，机组整体成本比变频螺杆空调机组降低10％以上；2. When used in fixed-frequency screw air conditioning units, it is not necessary to configure the frequency conversion cabinet. Under the premise of the same full load COP and partial load COP, the overall cost of the unit is reduced by more than 10% compared with the inverter screw air conditioning unit;

3、用于定频螺杆空调机组时，50％及以下部分负荷COP比定频定速螺杆空调机组高出20～30％，节能效果明显。3. For the fixed-frequency screw air-conditioning unit, the partial load COP of 50% and below is 20~30% higher than that of the fixed-frequency fixed-speed screw air-conditioning unit, and the energy-saving effect is obvious.

4、电机控制器主回路配置两个软启动器，一个软启动器驱动高速绕组，一个软启动器驱动低速绕组，软启动器之间输出互锁，共同分担电机的运行、启动，可满足电机频繁启动，延长驱动***寿命。4. The motor controller main circuit is equipped with two soft starters, one soft starter drives the high speed winding, one soft starter drives the low speed winding, and the soft starter outputs the interlock, which shares the running and starting of the motor, which can satisfy the motor. Start frequently to extend the life of the drive system.

5、软启动器直接接线到电机接线柱，双速电机六根接线柱，软启动器只用分别与电机对接6组动力线缆，接线简单。5. The soft starter is directly connected to the motor terminal, the two terminals of the two-speed motor, and the soft starter only uses 6 sets of power cables to be connected to the motor respectively, and the wiring is simple.

6、主回路配置的两个软启动器参数分别与双速电机绕组匹配，大电流软启动器驱动高速电机绕组，小电流软启动器驱动低速电机绕组，参数与高、低速电机对应，保护更安全，性能更好；6. The two soft starter parameters of the main circuit configuration are matched with the two-speed motor winding respectively. The high current soft starter drives the high speed motor winding, and the small current soft starter drives the low speed motor winding. The parameters correspond to the high and low speed motors, and the protection is more Safer and better performance;

7、使用软启动器驱动电机，启动过程中电流平滑，启动电流峰值可以调整，启动模式使用斜坡电流方案，可以使启动电流平滑，对高速，低速电机启动曲线更匹配。无二次冲击。软启动器本体具有比较全面的保护功能(过/欠压保护，逆相保护，三相电流不平衡保护，输入/输出缺相等)对电机保护更全面，更安全。7. Use the soft starter to drive the motor. The current is smooth during the startup process. The starting current peak can be adjusted. The startup mode uses the ramp current scheme to smooth the starting current and match the high-speed and low-speed motor starting curves. No secondary impact. The soft starter body has a comprehensive protection function (over/undervoltage protection, reverse phase protection, three-phase current unbalance protection, and equal input/output deficiencies) to make the motor protection more comprehensive and safer.

附图说明DRAWINGS

图1为根据本发明实施的可定频切换转速运行的螺杆压缩机容量控制***结构原理图。1 is a schematic structural view of a screw compressor capacity control system capable of operating at a fixed frequency switching speed according to an embodiment of the present invention.

图2为本发明螺杆压缩机容量控制***三速运行与切换为例的控制逻辑图。2 is a control logic diagram of a three-speed operation and switching of a screw compressor capacity control system of the present invention.

图1-2中附图标记为：定频压缩机1、旁通滑阀动作驱动器4、电机驱动器5、负荷测量装置6、***控制器7、旁通滑阀8、滑阀位置传感器9。The reference numerals in FIGS. 1-2 are: a fixed frequency compressor 1, a bypass spool operation driver 4, a motor driver 5, a load measuring device 6, a system controller 7, a bypass spool 8, and a spool position sensor 9.

图3为本发明电机驱动器基于双速电机驱动***的结构原理图。3 is a structural schematic diagram of a motor drive based on a two-speed motor drive system of the present invention.

图4为本发明电机驱动器基于双速电机驱动***其中一个具体实施例的电路结构图。4 is a circuit diagram of a motor driver based on one embodiment of a two-speed motor drive system of the present invention.

图5为本发明电机驱动器基于单软启动器驱动的主回路结构图。FIG. 5 is a structural diagram of a main circuit of a motor driver according to the present invention driven by a single soft starter.

图6为本发明电机驱动器基于单软启动器驱动另一个实施例的主回路结构图。Figure 6 is a block diagram showing the main circuit of another embodiment of the motor driver of the present invention based on a single soft starter drive.

图7为本发明电机驱动器双速运行与切换控制方法流程图。7 is a flow chart of a two-speed operation and switching control method of a motor driver according to the present invention.

图3-7中附图标记如下：1、定频压缩机(其中的电机绕组1、2、3为高速绕组，电机绕组4、5、6为低速绕组)，2、软启动器电控柜(QM1为高速软启动器，QM2为低速软启动器,QF为断路器)，3、控制器(CB)。The reference numerals in Figure 3-7 are as follows: 1. Fixed-frequency compressor (where

motor windings

1, 2, and 3 are high-speed windings,

motor windings

4, 5, and 6 are low-speed windings), and 2, soft starter electric control cabinet (QM1 is a high speed soft starter, QM2 is a low speed soft starter, QF is a circuit breaker), 3. Controller (CB).

图8为本发明电机驱动器5基于多速电机驱动的结构示意图。FIG. 8 is a schematic structural view of the motor driver 5 of the present invention based on multi-speed motor driving.

图9为本发明电机驱动器5基于多速电机驱动的一个具体实施例的电路结构图。Fig. 9 is a circuit configuration diagram of a specific embodiment of the motor driver 5 of the present invention based on multi-speed motor driving.

图10为发明本发明电机驱动器5基于多速电机驱动的三速运行与切换控制方法流程图。Fig. 10 is a flow chart showing the method of three-speed operation and switching control of the motor driver 5 of the present invention based on multi-speed motor driving.

具体实施方式Detailed ways

图1为根据本发明实施的可定频切换转速运行的螺杆压缩机容量控制***结构原理图。包括定频压缩机1、旁通滑阀动作驱动器4、电机驱动器5、负荷测量装置6、***控制器7、旁通滑阀8；定频压缩机1为螺杆压缩机和定频电机的组合，通过极对数切换来调节电机转速，螺杆压缩机上安装有可调节容量的旁通滑阀8，旁通滑阀8与旁通滑阀动作驱动器4连接并受其控制；还设置有滑阀位置传感器9，旁通滑阀位置传感器9与螺杆压缩机连接用于测量滑阀位置；电机驱动器5功能性连接于电机以实现双速或多速运行；负荷测量装置6用于检测压缩机运行负荷需求；旁通滑阀位置传感器9、旁通滑阀动作驱动器4、负荷测量装置6、电机驱动器5与***控制器7信号连接。1 is a schematic structural view of a screw compressor capacity control system capable of operating at a fixed frequency switching speed according to an embodiment of the present invention. The invention includes a fixed frequency compressor 1, a bypass spool action driver 4, a motor driver 5, a load measuring device 6, a system controller 7, and a bypass spool valve 8. The fixed frequency compressor 1 is a combination of a screw compressor and a fixed frequency motor. The motor speed is adjusted by pole-to-number switching. The screw compressor is equipped with a bypass valve 8 of adjustable capacity, and the bypass spool 8 is connected to and controlled by the bypass spool action driver 4; Position sensor 9, bypass spool position sensor 9 is connected to the screw compressor for measuring the position of the spool; motor drive 5 is functionally connected to the motor for two-speed or multi-speed operation; load measuring device 6 is used for detecting compressor operation The load demand; the bypass spool position sensor 9, the bypass spool action driver 4, the load measuring device 6, and the motor driver 5 are signally connected to the system controller 7.

采用上述可定频切换转速运行的螺杆压缩机及容量控制***的控制方法，其特征在于：旁通滑阀位置传感器9检测滑阀位置信号，***控制器7根据负荷测量装置6输入信号及滑阀位置信号，通过旁通滑阀动作驱动器4调节旁通滑阀8位置，并通过电机驱动器5来调节电机运行转速实现多速输出；或者在电机不同转速运行时，***控制器7对旁通滑阀8设定不同的可移动位置范围。The control method of the screw compressor and the capacity control system operating at the above-mentioned fixed-frequency switching speed is characterized in that the bypass spool position sensor 9 detects the spool position signal, and the system controller 7 inputs the signal and slides according to the load measuring device 6. The valve position signal adjusts the position of the bypass slide valve 8 through the bypass spool action driver 4, and adjusts the motor running speed through the motor driver 5 to realize multi-speed output; or when the motor runs at different speeds, the system controller 7 bypasses The spool 8 sets a different range of movable positions.

定频螺杆压缩机的特点是，按设计的压比，滑阀位越接近满位能效越高。小容量下输出时，尽可能使压缩机在较低速、滑阀位较高状态下运行，以获得较高的能效。The characteristic of the fixed-frequency screw compressor is that, according to the designed pressure ratio, the closer the spool position is to the full position, the higher the energy efficiency. When outputting at a small capacity, the compressor should be operated at a lower speed and a higher spool position as much as possible to obtain higher energy efficiency.

控制转速并匹配滑阀位置，目的是使压缩机处于功率最低(能效最高)的状态，举个例子：三速压缩机要输出30％的容量，理论上有三种输出方式：①高速(3000r/min)+滑阀30％；②中速(1500r/min)+滑阀60％；③低速(1000r/min)+滑阀90.9％；经过本发明的多次研究和实验，发现按第③种方式输出能效最高。Control the speed and match the position of the spool, the purpose is to make the compressor in the lowest power (highest energy efficiency) state, for example: the three-speed compressor should output 30% capacity, theoretically there are three output modes: 1 high speed (3000r / Min) + slide valve 30%; 2 medium speed (1500r / min) + spool valve 60%; 3 low speed (1000r / min) + spool valve 90.9%; after many studies and experiments of the present invention, found according to the third Mode output has the highest energy efficiency.

为了进一步实现这种控制方法，实现第③种方式的能效最高输出，本发明采用如图2所示的控制流程(三速运行为例的控制逻辑)：In order to further implement this control method and achieve the highest energy efficiency output of the third mode, the present invention adopts the control flow as shown in Fig. 2 (three-speed operation as an example of control logic):

定频压缩机1高速运行时，检测滑阀位置，如滑阀位≤H％且有减载需求时，定频压缩机1切入中速运行，否则继续在高速运行状态下运行；H％为压缩机高速运行时，阀位置移动下限；When the fixed frequency compressor 1 runs at high speed, the position of the slide valve is detected. If the spool position is ≤H% and there is demand for load shedding, the fixed frequency compressor 1 cuts into the medium speed, otherwise it will continue to run at high speed; H% is When the compressor is running at high speed, the valve position moves to the lower limit;

中速运行时，检测滑阀位置，如滑阀位≤M％且有减载需求时，定频压缩机1切入低速运行；如滑阀位在100％且有增载需求时，定频压缩机1切入高速运行，使滑阀位置在H％～100％；否则继续在中速运行状态下运行，保持中速运行的滑阀位置为M％～100％；其中，M％为压缩机中速运行时，阀位置移动下限；During medium speed operation, the position of the slide valve is detected. If the spool position is ≤M% and there is demand for load shedding, the fixed frequency compressor 1 cuts into low speed operation; if the spool position is 100% and there is load increase demand, fixed frequency compression Machine 1 cuts into high speed operation, so that the position of the spool valve is between H% and 100%; otherwise, it will continue to operate at medium speed operation, and the position of the spool valve that maintains the medium speed operation is M%~100%; among them, M% is in the compressor When the speed is running, the valve position moves to the lower limit;

低速运行时，检测滑阀位置，如滑阀位在100％且有增载需求，则切换到中速运行，保持中速运行的滑阀位置为M％～100％；否则继续保持低速运行，保持低速运行的滑阀位置为N％～100％；其中，N％为压缩机低速运行时，阀位置移动下限。When running at low speed, check the position of the spool valve. If the spool position is at 100% and there is load increase demand, switch to medium speed operation, and keep the position of the spool valve at medium speed running from M% to 100%; otherwise, continue to keep running at low speed. The position of the spool valve that keeps running at low speed is N% to 100%; where N% is the lower limit of the valve position when the compressor is running at low speed.

控制逻辑也可以如图2所示按低速或中速来启动。不管高速还是低速启动，只要在运行，就按图2所示的负荷需求结合滑阀的位置来调节就可。The control logic can also be started at low or medium speed as shown in Figure 2. Regardless of the high speed or low speed start, as long as it is running, it can be adjusted according to the load demand shown in Figure 2 combined with the position of the slide valve.

压缩机按照上述方法启动的一个具体实施例如下：按高速电机运行为例，滑阀定位在50％，此时输出容量为50％，比目标负荷高，负荷测量装置6反馈给***控制器7，需要减载。***控制器7发指令到电机驱动器5：停止高速电机，启动中速电机，启动时，滑阀会移动到66％，此时的负荷为33％，比目标负荷高，负荷测量装置6反馈给***控制器7，需要继续减载。***控制器7发指令到电机驱动器5：停止中速电机，启动低速电机，旁通滑阀8会根据负荷测量装置6的反馈，***控制器7发指令到滑阀驱动器4，让旁通滑阀8最终停在90.9％的位置，实现30％的负荷输出。(此过程是在压缩机容量由高转低的过程，高速切换到低速的过程，在实际运行中是最常见的。)A specific implementation of the compressor starting according to the above method is as follows: taking the high speed motor operation as an example, the spool valve is positioned at 50%, and the output capacity is 50%, which is higher than the target load, and the load measuring device 6 feeds back to the system controller 7 Need to load down. The system controller 7 sends a command to the motor driver 5: the high speed motor is stopped, and the medium speed motor is started. When starting, the spool valve moves to 66%, and the load at this time is 33%, which is higher than the target load, and the load measuring device 6 feeds back System controller 7, need to continue to load down. The system controller 7 sends a command to the motor driver 5: stops the medium speed motor, starts the low speed motor, and the bypass spool 8 sends a command to the spool driver 4 according to the feedback of the load measuring device 6, so that the bypass is slippery. Valve 8 eventually stops at 90.9% and achieves a 30% load output. (This process is a process in which the compressor capacity changes from high to low, and the process of switching from high speed to low speed is the most common in actual operation.)

以旁通滑阀8位置为0％对应螺杆压缩机最小容量，以旁通滑阀8位置为100％对应螺杆压缩机最大容量为例，***控制器7通过旁通滑阀位置传感器9探测旁通滑阀8所处滑阀位置，并控制不同转速时滑阀8可移动的位置在一定范围内，以实现螺杆压缩机满负荷至最小负荷下高性能系数。双速、三速运行的压缩机转速与推荐滑阀位置参见表1表2。The position of the bypass spool 8 is 0% corresponding to the minimum capacity of the screw compressor, and the position of the bypass spool 8 is 100% corresponding to the maximum capacity of the screw compressor, and the system controller 7 detects the side by the bypass spool position sensor 9. The slide valve 8 is located at the position of the spool valve, and the position at which the spool 8 can be moved at different speeds is controlled within a certain range to achieve a high performance coefficient of the screw compressor from full load to minimum load. See Table 2 in Table 1 for the compressor speeds of the two-speed and three-speed operation and the recommended spool position.

如表1所示，对于高、中、低转速极数分别为2、4、6的三速驱动螺杆压缩机，以极数为2高转速运行时，定义高转速运行时，滑阀开度位置下限H％在40～60％，优选H％在50％左右(即高转速运行时旁通滑阀可移动位置范围为H％～100％,对应压缩机输出容量范围50％～100％)，当滑阀位置移动至H％，而螺杆压缩机容量还需进一步调小时，螺杆压缩机将切换至以极数为4中转速运行；定义中转速运行时，滑阀开度位置移动下限为M％,一般M％在50～75％,优选66％左右(即滑阀开度位置可移动范围为M％～100％,对应压缩机输出容量范围33％～50％)，在中转速下，当滑阀位置移动至M％，而螺杆压缩机容量还需进一步调小时，螺杆压缩机将切换至以极数为6低转速运行，定义低转速运行时，滑阀开度位置移动下限为N％,一般N％在0～50％，(即滑阀开度位置可移动范围为N％～100％,对应压缩机输出容量范围：最小负荷～33％)，N值越小越好，N值越小说明压缩机最小负荷越小，受电机温升及压缩机可靠性方面影响。As shown in Table 1, for the three-speed drive screw compressor with high, medium and low speed poles of 2, 4, and 6, respectively, when the number of poles is 2 high speed, the spool opening is defined when the high speed is running. The lower limit of position H% is 40-60%, preferably H% is about 50% (that is, the movable position range of the bypass spool is H%-100% when the high-speed operation is performed, and the output capacity range of the compressor is 50%-100%) When the position of the spool moves to H%, and the capacity of the screw compressor needs to be further adjusted, the screw compressor will switch to run at the number of poles of 4; when the speed is defined, the lower limit of the position of the spool opening is M%, generally M% is 50 to 75%, preferably about 66% (ie, the movable range of the spool opening position is M% to 100%, corresponding to the compressor output capacity range of 33% to 50%), at medium speed When the position of the spool moves to M%, and the capacity of the screw compressor needs to be further adjusted, the screw compressor will switch to run at a low speed of 6 poles. When the low speed operation is defined, the lower limit of the position of the spool opening is N%, generally N% is 0-50%, (ie, the slide valve opening position can be moved from N% to 10%) 0%, corresponding to the compressor output capacity range: minimum load ~ 33%), the smaller the N value, the smaller the N value, the smaller the minimum load of the compressor, the motor temperature rise and the reliability of the compressor.

表1三速运行的压缩机输出容量与转速、滑阀位置关系表Table 1 Table of relationship between output capacity of the compressor and the speed and spool position of the three-speed operation

表1说明：中速下100％滑阀位与高速下H％滑阀位对应的压缩机容量相当；低速下100％滑阀位与中速下M％滑阀位对应的压缩机容量相当。Table 1 shows that the 100% spool position at medium speed is equivalent to the compressor capacity corresponding to the H% spool position at high speed; the 100% spool position at low speed is equivalent to the compressor capacity corresponding to the M% spool position at medium speed.

如表2所示，为对于高转速低转速极数分别为2和4的双速驱动螺杆压缩机，以极对数为1(极数为2)高转速运行时，控制器设定旁通滑阀位置移动下限为H％(即旁通滑阀位置可移动范围为H％～100％,对应压缩机输出容量范围50％～100％)，一般H％在50％左右，在高转速下，当滑阀位置移动≤H％，而螺杆压缩机容量还需进一步调小时，螺杆压缩机将切换至低转速运行(旁通滑阀位置可移动范围为N％～100％,对应压缩机输出容量范围：最小负荷～50％)。As shown in Table 2, for a two-speed drive screw compressor with high speed and low speed poles of 2 and 4 respectively, when the pole number is 1 (pole number is 2), the controller sets the bypass. The lower limit of the position of the spool valve is H% (ie, the movable range of the bypass spool valve is H%～100%, corresponding to the compressor output capacity range of 50%～100%), generally H% is about 50%, at high speed When the position of the spool valve moves ≤H%, and the capacity of the screw compressor needs to be further adjusted, the screw compressor will switch to the low speed operation (the bypass valve position can be moved from N% to 100%, corresponding to the compressor output). Capacity range: minimum load ~ 50%).

表2双速运行的压缩机输出容量与转速、滑阀位置关系表Table 2: Table of relationship between output capacity of the compressor and the speed and spool position of the two-speed operation

表2说明：低速下100％滑阀位与高速下H％滑阀位对应的压缩机容量相当。Table 2 shows that the 100% spool position at low speed is equivalent to the compressor capacity corresponding to the H% spool position at high speed.

用于本发明的电机驱动器5有多种实施方式，常规的驱动方式，如“一个软启动器+两个/多个接触器驱动”也可以适用于本发明，也纳入保护范围。除此之外，本发明的进一步特色是主回路配置两个软启动器，一个软启动器驱动电机高速绕组，一个软启动器驱动电机的中速与低速绕组，软启动器之间输出互锁，共同分担电机的运行、启动，可满足电机频繁启动，延长驱动***寿命；主回路配置的两个软启动器参数分别与双速电机绕组匹配，大电流软启动器驱动高速电机绕组，小电流软启动器驱动低速电机绕组，参数与高、低速电机对应，保护更安全，性能更好。使定频压缩机1不同转速运行时，滑阀控制在合理的行程范围内，达到满载和部分负荷高效率运行。The motor driver 5 used in the present invention has various embodiments, and a conventional driving method such as "one soft starter + two/multiple contactor drives" can also be applied to the present invention, and also includes the scope of protection. In addition, the present invention is further characterized in that the main circuit is configured with two soft starters, one soft starter drives the motor high speed winding, one soft starter drives the medium speed and low speed winding of the motor, and the soft starter outputs an interlock. Sharing the operation and start-up of the motor can meet the frequent start of the motor and prolong the life of the drive system; the two soft starter parameters of the main circuit are matched with the two-speed motor winding respectively, and the high-current soft starter drives the high-speed motor winding with small current. The soft starter drives the low speed motor windings, and the parameters correspond to the high and low speed motors for safer protection and better performance. When the fixed frequency compressor 1 is operated at different speeds, the spool valve is controlled within a reasonable stroke range to achieve full load and partial load high efficiency operation.

如图3所示，为本发明电机驱动器基于双速电机驱动***的结构原理图。其中控制器3与软启动器电控柜2连接，软启动器电控柜2与定频压缩机1连接；软启动器电控柜2中设置一个断路器QF、一个高速软启动器QM1、和一个低速软启动器QM2；定频压缩机1中包括一组高速绕组(电机绕组1、2、3)和一组低速绕组(电机绕组4、5、6)。As shown in FIG. 3, the schematic diagram of the structure of the motor driver based on the two-speed motor drive system of the present invention is shown. The controller 3 is connected with the soft starter electric control cabinet 2, the soft starter electric control cabinet 2 is connected with the fixed frequency compressor 1; the soft starter electric control cabinet 2 is provided with a circuit breaker QF and a high speed soft starter QM1. And a low speed soft starter QM2; the fixed frequency compressor 1 includes a set of high speed windings (

motor windings

1, 2, 3) and a set of low speed windings (

motor windings

4, 5, 6).

如图4所示为图3中为本发明电机驱动器基于双速电机驱动***其中一个具体实施例的电路结构图。其中，高速软启动器QM1和低速软启动器QM2的控制端各自并联连接在控制器3上；高速软启动器QM1和低速软启动器QM2的输入端(L1、L2、L3各端子)各相分别并联在断路器QF断路开关后的三相接线端上；高速软启动器QM1的输出端(L4、L5、L6各端子)依次连接在定频压缩机1的高速绕组各绕组上(电机绕组1、2、3)；低速软启动器QM2的输出端(L4、L5、L6各端子)依次连接在定频压缩机1的低速绕组各绕组上(电机绕组4、5、6)。FIG. 4 is a circuit structural diagram of the motor driver according to the present invention based on a specific embodiment of a two-speed motor driving system. Wherein, the control ends of the high-speed soft starter QM1 and the low-speed soft starter QM2 are respectively connected in parallel to the controller 3; the high-speed soft starter QM1 and the low-speed soft starter QM2 input terminals (L1, L2, L3 terminals) each phase Parallel to the three-phase terminals of the circuit breaker QF disconnect switch; the output terminals of the high-speed soft starter QM1 (L4, L5, L6 terminals) are sequentially connected to the windings of the high-speed winding of the fixed-frequency compressor 1 (motor winding 1, 2, 3); The output terminals (terminals L4, L5, and L6) of the low-speed soft starter QM2 are sequentially connected to the windings of the low-speed winding of the fixed-frequency compressor 1 (

motor windings

4, 5, and 6).

图5为本发明电机驱动器5基于单软启动器驱动的主回路结构图。其为图4中实施例的一个变种实施例，与图4的区别即使用两个断路器QF1和QF2，各断路器连接一个软启动器，然后通过两个软启动器驱动双速电机。高速软启动器QM1和低速软启动器QM2根据断路器QF1和QF2的通断，分别启动，实现基于单软启动器驱动双速电机。Fig. 5 is a structural diagram of the main circuit of the motor driver 5 of the present invention based on a single soft starter drive. It is a variant embodiment of the embodiment of Figure 4, which differs from Figure 4 in that two circuit breakers QF1 and QF2 are used, each circuit breaker being connected to a soft starter, and then the two-speed motor is driven by two soft starters. The high-speed soft starter QM1 and the low-speed soft starter QM2 are respectively activated according to the on/off of the circuit breakers QF1 and QF2, and the two-speed motor is driven based on a single soft starter.

图6为本发明电机驱动器5基于单软启动器驱动另一个实施例的主回路结构图。其在图5中两个断路器QF1和QF2的前方主路上连接了一个隔离开关QS；通过隔离开关QS构成两个软启动器可选择的实现基于单软启动器驱动双速电机。Figure 6 is a block diagram showing the main circuit of another embodiment of the motor driver 5 of the present invention based on a single soft starter drive. It is connected with an isolating switch QS on the front main road of the two circuit breakers QF1 and QF2 in Fig. 5; two soft starters are formed by the isolating switch QS to realize the driving of the two-speed motor based on the single soft starter.

图7为本发明电机控制器基于上述双速运行与切换控制方法流程图。其中：7 is a flow chart of the motor controller of the present invention based on the above two-speed operation and switching control method. among them:

电机启动方式为软启动，启动模式为斜坡电流模式，对电机启动电流峰值限流，调节启动电压，电流平滑上升使电机转速达到额定转速完成电机启动，电机的高速绕组1、2、3对应一个大电流的软启动器(QM1)，保护参数按高速电流保护，启动电流也按照高速电流限制，保证启动电流平滑；电机的低速绕组4、5、6对应一个低速电流的软启动器(QM2)，保护参数按低速电流保护，启动电流也按照低速电流限制，保证启动电流平滑；The motor starting mode is soft start, the starting mode is ramp current mode, the motor starting current peak current limit, the starting voltage is adjusted, the current rises smoothly, the motor speed reaches the rated speed to complete the motor starting, and the

high speed windings

1, 2, 3 of the motor correspond to one. High-current soft starter (QM1), protection parameters are protected by high-speed current, and the starting current is also limited by high-speed current to ensure smooth starting current; the low-

speed windings

4, 5, and 6 of the motor correspond to a low-speed current soft starter (QM2) The protection parameter is protected by low-speed current, and the starting current is also limited according to the low-speed current to ensure smooth starting current;

电机高速与低速切换方式：当高速切低速时，先高速软启动器QM1停止输出，电机自由停车数秒之后启动低速软启动器QM2启动电机使电机运行在低速；当低速切高速时，先低速软启动器QM2停止输出，电机自由停车数秒之后启动高速软启动器QM1启动电机使电机运行在高速；High-speed and low-speed switching mode of the motor: When the high speed cuts the low speed, the high-speed soft starter QM1 stops outputting. After the motor is free to stop for a few seconds, the low-speed soft starter is started. QM2 starts the motor to make the motor run at low speed; when the low speed cuts the high speed, the low speed is soft first. The starter QM2 stops outputting, and the motor starts to stop for a few seconds and then starts the high-speed soft starter. QM1 starts the motor to make the motor run at high speed;

两个软启动器共同分担一个电机的启动、运行，软启动器一个运行则另一个停止，可满足频繁启动的需求，延长使用寿命；Two soft starters share the start and run of one motor, and one start of the soft starter and the other stop, which can meet the requirements of frequent start and extend the service life;

所有启动及运行过程中，软启动器将电流信号反馈给控制器，控制器按照电流值保护电机的启动及运行情况。During all startup and operation, the soft starter feeds back the current signal to the controller, and the controller protects the start and operation of the motor according to the current value.

图8为本发明电机控制器基于多速电机驱动的结构示意图。其与双速启动的区别是，一个软启动器后配多个接触器。具体为：控制器3与软启动器电控柜2连接，软启动器电控柜2与定频压缩机1连接；软启动器电控柜2中设置一个断路器QF、一个高速软启动器QM1、一个低速软启动器QM2、和N个启动接触器(KM1～KMN为启动接触器)；定频压缩机1中包括多组绕组，至少一组高速绕组(电机绕组1、2、3)和一组低速绕组(电机绕组N、N+1、N+2)。FIG. 8 is a schematic structural view of a motor controller according to the present invention driven by a multi-speed motor. The difference between it and the two-speed start is that a soft starter is equipped with multiple contactors. Specifically, the controller 3 is connected to the soft starter electric control cabinet 2, the soft starter electric control cabinet 2 is connected with the fixed frequency compressor 1; the soft starter electric control cabinet 2 is provided with a circuit breaker QF and a high speed soft starter. QM1, a low-speed soft starter QM2, and N start contactors (KM1~KMN are start contactors); the fixed frequency compressor 1 includes multiple sets of windings, at least one set of high speed windings (

motor windings

1, 2, 3) And a set of low speed windings (motor windings N, N+1, N+2).

图9为本发明电机控制器基于多速电机驱动的一个具体实施例的电路结构图。其中，高速软启动器QM1和低速软启动器QM2的控制端各自并联连接在控制器3上；高速软启动器QM1和低速软启动器QM2的输入端(L1、L2、L3各端子)各相分别并联在断路器QF断路开关后的三相接线端上；高速软启动器QM1的输出端(L4、L5、L6各端子)通过启动接触器KM1依次连接在定频压缩机1的高速绕组各绕组上(电机绕组1、2、3)；低速软启动器QM2的输出端(L4、L5、L6各端子)并联输出至少两端，其中一端通过启动接触器KMN依次连接在定频压缩机1的低速绕组各绕组上(N、N+1、N+2)；另一端通过启动接触器KM2依次连接在定频压缩机1的中速绕组各绕组上(4、5、6)；依次类推。Figure 9 is a circuit diagram of a specific embodiment of a motor controller based on multi-speed motor drive of the present invention. Wherein, the control ends of the high-speed soft starter QM1 and the low-speed soft starter QM2 are respectively connected in parallel to the controller 3; the high-speed soft starter QM1 and the low-speed soft starter QM2 input terminals (L1, L2, L3 terminals) each phase Parallel to the three-phase terminals of the circuit breaker QF disconnect switch; the output terminals of the high-speed soft starter QM1 (L4, L5, L6 terminals) are sequentially connected to the high-speed windings of the fixed-frequency compressor 1 through the start contactor KM1. On the winding (motor winding 1, 2, 3); the output end of the low-speed soft starter QM2 (L4, L5, L6 terminals) is connected in parallel at least two ends, one end of which is connected to the fixed frequency compressor 1 through the start contactor KMN The lower speed windings are on the windings (N, N+1, N+2); the other end is connected to the windings of the medium speed winding of the fixed frequency compressor 1 through the start contactor KM2 (4, 5, 6); .

图10为发明本发明电机驱动器5基于多速电机驱动的三速运行与切换控制方法流程图。其中电机速度切换方式为：当高速切低速或中速时，先高速软启动器停止输出，电机自由停车数秒之后，启动低速软启动器，启动电机使电机运行在低速或中速；当中速切低速时，先低速软启动器停止输出，电机自由停车数秒之后，电机绕组从中速绕组切换到低速绕组，然后再次启动低速软启动器，启动电机使电机运行在低速；当低速切高速时，先低速软启动器停止输出，电机自由停车数秒之后，启动高速软启动器，启动电机使电机运行在高速。Fig. 10 is a flow chart showing the method of three-speed operation and switching control of the motor driver 5 of the present invention based on multi-speed motor driving. The motor speed switching mode is: when the high speed cuts the low speed or the medium speed, the high speed soft starter stops outputting, and after the motor is free to stop for a few seconds, the low speed soft starter is started, the motor is started to make the motor run at low speed or medium speed; At low speed, the low-speed soft starter stops outputting. After the motor is free to stop for a few seconds, the motor winding switches from the medium-speed winding to the low-speed winding, and then starts the low-speed soft starter again, starting the motor to make the motor run at low speed; when cutting the high speed at low speed, first The low-speed soft starter stops outputting, and after the motor is free to stop for a few seconds, the high-speed soft starter is started, and the motor is started to make the motor run at high speed.

电机启动之前，控制器3控制需要启动的绕组对应的接触器KMN先吸合，然后控制软启动器QM启动。Before the motor is started, the controller 3 controls the contactor KMN corresponding to the winding to be started to first pick up, and then controls the soft starter QM to start.

切换时，控制器先停止正在工作的启动器QM，再释放绕组对应的接触器KM，然后再启动需要运行的启动器QM，再连通绕组对应的接触器KM。When switching, the controller first stops the working starter QM, then releases the corresponding contactor KM of the winding, and then starts the starter QM that needs to be operated, and then connects the contactor KM corresponding to the winding.

先高速软启动器QM1停止输出，电机自由停车数秒之后启动低速软启动器QM2启动电机使电机运行在低速；当高速切中速时，中速软启动器QM2启动电机使电机运行在中速；从中速切低速时候，低速软启动器QM2启动电机使电机运行在低速。The high-speed soft starter QM1 stops outputting, the motor is free to stop for a few seconds, then the low-speed soft starter is started. QM2 starts the motor to make the motor run at low speed; when the high-speed cutting medium speed, the medium-speed soft starter QM2 starts the motor to make the motor run at medium speed; When the speed is low, the low speed soft starter QM2 starts the motor to make the motor run at low speed.

多速(速度档位大于2)电机与软启动器的匹配规则：大电流软启动器驱动高速电机绕组，小电流软启动器驱动低速电机绕组。Multi-speed (speed gear greater than 2) matching rules between motor and soft starter: high current soft starter drives high speed motor winding, small current soft starter drives low speed motor winding.

高速软启动器的电流上限由最高绕组的转速N0决定，低速软启动器的电流上限为中间转速绕组的转速N1决定，绕组匹配规则对应为：最高绕组的转速N0≥绕组转速＞中间转速绕组的转速N1，均由高速软启动驱动；绕组转速≤中间转速绕组的转速N1；都由低速软启动器驱动。The upper limit of the current of the high speed soft starter is determined by the speed N0 of the highest winding, and the upper limit of the current of the low speed soft starter is determined by the speed N1 of the intermediate speed winding. The winding matching rule corresponds to: the speed of the highest winding N0 ≥ the winding speed > the intermediate speed winding The speed N1 is driven by a high speed soft start; the winding speed ≤ the speed of the intermediate speed winding N1; both are driven by a low speed soft starter.

双速和多速电机驱动***主回路配置不限于以上形式，凡使用软启动器驱动双速或多速电机的方案都在本发明的保护范围内。。The main circuit configuration of the two-speed and multi-speed motor drive system is not limited to the above, and any solution that uses a soft starter to drive a two-speed or multi-speed motor is within the scope of the present invention. .

由此，本发明有益效果如下：Thus, the beneficial effects of the present invention are as follows:

3、用于定频螺杆空调机组时，50％及以下部分负荷COP比定频定速螺杆空调机组高出20～30％,进而显著提升IPLV，节能效果明显。3. For the fixed-frequency screw air-conditioning unit, the partial load COP of 50% and below is 20~30% higher than that of the fixed-frequency fixed-speed screw air-conditioning unit, which significantly increases the IPLV and has obvious energy-saving effect.

Claims

一种可定频切换转速运行的螺杆压缩机容量控制***，包括含定频电机的螺杆压缩机，螺杆压缩机上安装有可调节容量的旁通滑阀，还设置旁通滑阀动作驱动器、电机驱动器、控制器以及负荷测量装置，旁通滑阀与旁通滑阀动作驱动器信号连接、并受旁通滑阀动作驱动器控制，其特征在于：还设置旁通滑阀位置传感器，旁通滑阀位置传感器与螺杆压缩机连接用于测量滑阀位置，负荷测量装置用于检测压缩机运行负荷需求，电机驱动器与定频压缩机连接；旁通滑阀位置传感器、旁通滑阀动作驱动器、负荷测量装置、电机驱动器与控制器信号连接。A screw compressor capacity control system capable of operating at a fixed frequency switching speed, comprising a screw compressor with a fixed frequency motor, a bypass spool valve with adjustable capacity installed on the screw compressor, and a bypass slide valve action driver and motor The drive, the controller and the load measuring device, the bypass slide valve is connected with the bypass spool action driver signal, and is controlled by the bypass spool action driver, and is characterized in that a bypass slide valve position sensor and a bypass slide valve are also provided. The position sensor is connected to the screw compressor for measuring the position of the spool, the load measuring device is used to detect the load demand of the compressor, the motor driver is connected with the fixed frequency compressor, the position sensor of the bypass valve, the action actuator of the bypass spool, and the load The measuring device, the motor driver and the controller signal are connected.
根据权利要求1所述的可定频切换转速运行的螺杆压缩机容量控制***，其特征在于：所述电机驱动器设置为可实现定频电机速度双速或多速运行以及在速度档位间进行切换；定频电机包括至少一个绕组，通过接线方式切换绕组的极数和转速。The screw compressor capacity control system capable of operating at a fixed-frequency switching speed according to claim 1, wherein the motor driver is set to realize a two-speed or multi-speed operation of the fixed-frequency motor speed and between the speed gears. Switching; the fixed frequency motor includes at least one winding, and the number of poles and the number of revolutions of the winding are switched by means of wiring.
根据权利要求1或2所述的可定频切换转速运行的螺杆压缩机容量控制***，其特征在于：电机驱动器包括至少一个软启动器和和两个/多个接触器；软启动器通过两个/多个接触器选择性连接电机绕组。A screw compressor capacity control system capable of operating at a fixed frequency switching speed according to claim 1 or 2, wherein the motor driver comprises at least one soft starter and two or more contactors; the soft starter passes two One or more contactors are selectively connected to the motor windings.
根据权利要求3所述的可定频切换转速运行的螺杆压缩机容量控制***，其特征在于：定频电机包括至少一组高速绕组和至少一组低速绕组；相对应的，电机驱动器包括一个高速软启动器和一个低速软启动器，和至少一个断路器；断路器与低速软启动器和高速软启动器分别连接；高速软启动器与定频电机的高速绕组连接；低速软启动器与定频电机的低速绕组连接。A screw compressor capacity control system operable at a constant frequency switching speed according to claim 3, wherein the fixed frequency motor comprises at least one set of high speed windings and at least one set of low speed windings; correspondingly, the motor drive comprises a high speed a soft starter and a low speed soft starter, and at least one circuit breaker; the circuit breaker is connected to the low speed soft starter and the high speed soft starter respectively; the high speed soft starter is connected to the high speed winding of the fixed frequency motor; the low speed soft starter is fixed The low speed winding connection of the frequency motor.
根据权利要求4所述的可定频切换转速运行的螺杆压缩机容量控制***，其特征在于：当定频压缩机中还包括至少一组转速位于高速绕组和低速绕组之间的中速绕组时，所述软启动器电控柜中还设置若干启动接触器；其中高速软启动器的输出端通过一个启动接触器与定频压缩机的高速绕组连接；低速软启动器的输出端上设置若干并列的启动接触器，该若干并列的启动接触器均按一一对接的方式连接低速绕组和各中速绕组。A screw compressor capacity control system operable at a constant frequency switching speed according to claim 4, wherein when the fixed frequency compressor further comprises at least one set of intermediate speed windings between the high speed winding and the low speed winding The soft starter electric control cabinet is further provided with a plurality of start contactors; wherein the output end of the high speed soft starter is connected to the high speed winding of the fixed frequency compressor through a start contactor; the output end of the low speed soft starter is set A parallel start contactor that connects the low speed winding and each intermediate speed winding in a one-to-one connection.
根据权利要求4所述的可定频切换转速运行的螺杆压缩机容量控制***，其特征在于：在高速软启动器和一个低速软启动器前方各设置一个断路器；两个断路器并联在电源上。A screw compressor capacity control system capable of operating at a fixed frequency switching speed according to claim 4, wherein: a circuit breaker is disposed in front of the high speed soft starter and a low speed soft starter; on.
根据权利要求6所述的可定频切换转速运行的螺杆压缩机容量控制***，其特征在于：两个断路器的前方主路上连接一个隔离开关QS；通过隔离开关QS构成两个断路器可选择地与各自软启动器连接。The screw compressor capacity control system capable of operating at a fixed frequency switching speed according to claim 6, wherein: an isolation switch QS is connected to the front main road of the two circuit breakers; and two circuit breakers are selected by the isolation switch QS. Ground connected to the respective soft starter.
采用上述权利要求1-7任一项所述可定频切换转速运行的螺杆压缩机容量控制***的容量控制方法，其特征在于：在电机处于不同转速运行时，控制器根据负荷测量装置获取负荷需求，旁通滑阀位置传感器检测滑阀开度位置信号，控制器根据负荷需求及滑阀位置信号，通过电机驱动器来调节电机运行转速实现多速输出和/或切换，并通过旁通滑阀动作驱动器调节旁通滑阀开度位置，使旁通滑阀开度位置处于设定的开度范围，所述开度范围使滑阀开度位置始终与电机速度保持着向电机低速运转和滑阀位高开度位置的趋势运行。A capacity control method for a screw compressor capacity control system capable of operating at a fixed-frequency switching speed according to any one of claims 1 to 7, characterized in that: when the motor is operated at different speeds, the controller acquires a load according to the load measuring device Demand, the bypass spool position sensor detects the position of the slide valve opening position, and the controller adjusts the running speed of the motor through the motor driver to achieve multi-speed output and/or switching according to the load demand and the spool position signal, and passes the bypass spool valve The action driver adjusts the position of the bypass spool opening so that the position of the bypass spool opening is within a set opening range, and the opening range keeps the position of the spool open always at a low speed to the motor and slips to the motor speed The trend of the valve position at the high opening position is running.
采用权利要求8所述可定频切换转速运行的螺杆压缩机容量控制***的容量控制方法，其特征在于：通过电机驱动器来调节电机运行转速实现三速输出和/或切换具体流程如下：A capacity control method for a screw compressor capacity control system capable of operating at a fixed frequency switching speed according to claim 8, wherein the three-speed output and/or switching of the motor running speed by the motor driver is as follows:

定频压缩机高速运行时，检测滑阀开度位置，如滑阀开度位置≤H％且有减载需求时，定频压缩机切入中速运行，否则继续在高速运行状态下运行；H％为在控制器中设定的压缩机高速运行时滑阀开度位置下限；When the fixed-frequency compressor runs at high speed, the position of the spool opening is detected. If the position of the spool opening is ≤H% and there is demand for load shedding, the fixed-frequency compressor cuts into the medium-speed operation, otherwise it continues to run at high-speed operation; % is the lower limit of the spool opening position when the compressor is set to operate at high speed in the controller;

中速运行时，检测滑阀开度位置，如滑阀开度位置≤M％且有减载需求时，定频压缩机切入低速运行；如滑阀位在100％且有增载需求时，定频压缩机切入高速运行，使滑阀开度位置在H％～100％；否则继续在中速运行状态下运行，保持中速运行的滑阀开度位置为M％～100％；其中，M％为压缩机中速运行时滑阀开度位置下限；During medium speed operation, the position of the slide valve opening is detected. If the position of the valve opening is ≤ M% and there is demand for load shedding, the fixed frequency compressor cuts into low speed operation; if the spool position is 100% and there is demand for load increase, The fixed-frequency compressor cuts into high-speed operation, so that the position of the spool opening is in the range of H% to 100%; otherwise, it continues to operate in the medium-speed operation state, and the position of the spool opening of the medium-speed operation is M% to 100%; M% is the lower limit of the spool opening position when the compressor is running at medium speed;

低速运行时，检测滑阀开度位置，如滑阀位在100％且有增载需求，则切换到中速运行，保持中速运行的滑阀开度位置为M％～100％；否则继续保持低速运行，保持低速运行的滑阀开度位置为N％～100％；其中，N％为压缩机低速运行时滑阀开度位置下限。When running at low speed, check the position of the slide valve opening. If the spool position is at 100% and there is load increase demand, switch to medium speed operation, and keep the position of the spool opening of medium speed operation from M% to 100%; otherwise continue Maintaining low speed operation, the position of the spool opening of the low speed operation is N% to 100%; wherein, N% is the lower limit of the position of the spool opening when the compressor is running at low speed.
采用权利要求8所述可定频切换转速运行的螺杆压缩机容量控制***的容量控制方法，其特征在于：通过电机驱动器来调节电机运行转速实现双速输出和/或切换具体流程如下：A capacity control method for a screw compressor capacity control system capable of operating at a fixed frequency switching speed according to claim 8, wherein the motor drive speed is adjusted to achieve a two-speed output and/or switching as follows:

定频压缩机高速运行时，检测滑阀开度位置，如滑阀开度位置≤H％且有减载需求时，定频压缩机切入低速运行，否则继续在高速运行状态下运行；H％为在控制器中设定的压缩机高速运行时滑阀开度位置下限；低速运行时，检测滑阀开度位置，如滑阀位在100％且有增载需求，则切换到高速运行，保持高速运行的滑阀开度位置为H％～100％；否则继续保持低速运行，保持低速运行的滑阀开度位置为N％～100％；其中，N％为压缩机低速运行时滑阀开度位置下限。When the fixed-frequency compressor runs at high speed, the position of the slide valve opening is detected. If the position of the spool opening is ≤H% and there is demand for load shedding, the fixed-frequency compressor cuts into low-speed operation, otherwise it will continue to run under high-speed operation; H% The lower limit of the spool opening position for the high speed operation of the compressor set in the controller; when the low speed operation is performed, the position of the spool opening is detected. If the spool position is 100% and there is an increase demand, switch to high speed operation. Keep the high-speed operation of the spool opening position from H% to 100%; otherwise, continue to maintain the low speed operation, and maintain the low-speed operation of the spool opening position from N% to 100%; wherein, N% is the spool valve when the compressor is running at low speed. The lower limit of the opening position.
采用权利要求8-10之一所述可定频切换转速运行的螺杆压缩机容量控制***的容量控制方法，其特征在于：电机驱动器电源启动主回路配置两个软启动器时，高速软启动器控制电机的高速绕组，低速软启动器控制电机的低速绕组；高速软启动器和低速软启动器之间输出互锁，共同分担电机的运行、启动；***控制器根据负荷测量装置的输入信号及滑阀位置信号，通过旁通滑阀动作驱动器调节旁通滑阀位置，及通过电机驱动器来调节电机运行转速；电机不同转速运行时，旁通滑阀开度位置根据设定范围调整。A capacity control method for a screw compressor capacity control system capable of operating at a constant frequency switching speed according to any one of claims 8-10, characterized in that: when the motor driver power supply starts the main circuit and configures two soft starters, the high speed soft starter Control the high speed winding of the motor, the low speed soft starter controls the low speed winding of the motor; the output interlock between the high speed soft starter and the low speed soft starter shares the operation and start of the motor; the system controller inputs the signal according to the load measuring device and The position signal of the spool valve is adjusted by the bypass spool action driver to adjust the position of the bypass slide valve, and the motor drive speed is adjusted by the motor driver; when the motor is running at different speeds, the position of the bypass spool opening is adjusted according to the set range.
采用权利要求8-10之一所述可定频切换转速运行的螺杆压缩机容量控制***的容量控制方法，其特征在于：高速软启动器的电流上限由最高绕组的转速N0决定，低速软启动器的电流上限为中间转速绕组的转速N1决定，绕组匹配规则对应为：最高绕组的转速N0≥绕组转速＞中间转速绕组的转速N1，均由高速软启动驱动；绕组转速≤中间转速绕组的转速N1；都由低速软启动器驱动。A capacity control method for a screw compressor capacity control system operating at a fixed-frequency switching speed according to any one of claims 8-10, characterized in that the upper limit of the current of the high-speed soft starter is determined by the maximum winding speed N0, and the low-speed soft start The upper limit of the current is determined by the speed N1 of the intermediate speed winding. The winding matching rule corresponds to: the highest winding speed N0 ≥ the winding speed > the intermediate speed winding speed N1, both driven by the high speed soft start; the winding speed ≤ the intermediate speed winding speed N1; are driven by a low speed soft starter.
采用权利要求8-10之一所述可定频切换转速运行的螺杆压缩机容量控制***的容量控制方法，其特征在于：电机启动方式为软启动，启动模式为斜坡电流模式，对电机启动电流峰值限流，调节启动电压，电流平滑上升使电机转速达到额定转速完成电机启动，电机的高速绕组对应一个高速软启动器，保护参数按高速电流保护限制，启动电流也按照高速电流限制，保证启动电流平滑；电机的低速绕组对应低速软启动器，保护参数按低速电流保护，启动电流也按照低速电流限制，保证启动电流平滑。A capacity control method for a screw compressor capacity control system capable of operating at a fixed frequency switching speed according to any one of claims 8-10, characterized in that the motor starting mode is a soft start, the starting mode is a ramp current mode, and the motor starting current is Peak current limit, adjust the starting voltage, the current rises smoothly, the motor speed reaches the rated speed to complete the motor start, the high-speed winding of the motor corresponds to a high-speed soft starter, the protection parameter is limited by the high-speed current protection, and the starting current is also limited according to the high-speed current. The current is smooth; the low speed winding of the motor corresponds to the low speed soft starter, the protection parameter is protected by the low speed current, and the starting current is also limited according to the low speed current to ensure the starting current is smooth.
采用权利要求8-10之一所述可定频切换转速运行的螺杆压缩机容量控制***的容量控制方法，其特征在于：电机速度切换方式为：当高速切低速或中速时，先高速软启动器停止输出，电机自由停车数秒之后，启动低速软启动器，启动电机使电机运行在低速或中速；当中速切低速时，先低速软启动器停止输出，电机自由停车数秒之后，电机绕组从中速绕组切换到低速绕组，然后再次启动低速软启动器，启动电机使电机运行在低速；当低速切高速时，先低速软启动器停止输出，电机自由停车数秒之后，启动高速软启动器，启动电机使电机运行在高速。A capacity control method for a screw compressor capacity control system capable of operating at a constant frequency switching speed according to any one of claims 8-10, characterized in that: the motor speed switching mode is: when the high speed cuts the low speed or the medium speed, the high speed soft The starter stops outputting, and after the motor is free to stop for a few seconds, the low speed soft starter is started, the motor is started to make the motor run at low speed or medium speed; when the medium speed cuts low speed, the low speed soft starter stops outputting, and the motor freely stops for a few seconds, the motor winding Switching from the medium speed winding to the low speed winding, then starting the low speed soft starter again, starting the motor to make the motor run at low speed; when cutting the high speed at low speed, the low speed soft starter stops outputting, and after the motor is free to stop for a few seconds, the high speed soft starter is started. Start the motor to run the motor at high speed.