Question:
What are the possibilities to supply ECS-axis modules alternatively to the ECS-supply modules and what has to be considered?
Answer:
General:
- The parallel operation of several ECS power supply modules to increase the power available in multi-axis systems is not permissible due to the design of the devices. This situation is due to the internal safety functions in the ECS power supply module and the lack of synchronisation for the internal brake chopper
- The parallel operation of ECS power supply modules with brake choppers 935x or in drive con-trollers with integrated brake choppers to increase the regenerative power is in principle per-missible. To implement this configuration the internal brake resistor in the ECS power supply module is to be deactivated. The necessary settings are described in the operating instructions for the power supply module.
- The operation of 9300, 8200 vector on the ECS power supply module is not permitted due to the design of the devices. The situation is due to the behaviour of the 9300 and 8200 vector devices during charging. The charging current is limited by the integrated charging resistors. As a result the charging of the DC bus is delayed to such an extent that a timeout can occur in the ECS power supply module. It is only allowed to operate devices on ECS power supply modules that do not have any charging current limitation, or on which the charging current limitation can be deactivated.
Supply via a standard B6 bridge:
It is
in principle possible to operate ECS axis modules via a B6 bridge rectifier. The rectifier must be matched to the characteristics of the ECS axis modules, i. e. it must be able to provide the necessary power and be able to withstand the voltage in generator mode. In the normal ca-se, diodes with an electric strength of >=1600V are used in this type of rectifier.
The operation of the brake chopper 935x on such a rectifier is permitted provided the operating instructions for the 935x devices are observed.
For the internal test on this supply variant, a rectifier from IXYS was used. The data are listed in the following:
Type: IXYS VUO60-16NO3
IdAV@Tc = 85 °C = 72 A
Dimensions: WxHxD (32 mm x 63 mm x 25 mm) – without heatsink
The mains input fuse protection and the selection of the cable cross-sections are made in ac-cordance with applicable VDE regulations.
To protect the mains input, it is imperative that varistors to suit the nominal mains voltage are used. (e. g. for 230 V mains: varistor type S20K250; for 400 V mains varistor type S20K460, for 480 V mains: varistor type S20K520)
The varistors must be installed on the AC side between the mains phases.
Supply via a regenerative power supply module 9340
This operating mode for setting up regenerative power return to the mains on ECS multi-axis systems is
in principle permitted. Dimensioning guidelines are available at Lenze.
Supply via power supply module 9360
Operation on series 936x power supply modules is
in principle permitted. In this case the di-mensioning guidelines for these devices are to be observed.
It is also permitted to supply power via three-phase bridge rectifiers from other manufacturers. In this case the dimensioning guidelines from the related manufacturer are to be observed. In principle the RFI filters and mains chokes for the ECS servo system are also approved for this DC bus layout.
The parallel operation of ECS power supply modules with 936x or 934x to increase the avail-able power or regeneration in multi-axis systems
is not allowed due to the design of the de-vices
Direct supply of the DC bus via DC source (e. g. battery)
In practice this variant could be used to supply power in emergency situations, i. e. for example a UPS (Uninterruptible Power Supply) is used that continues to supply the machine with power on a mains failure such that the machine can be placed in a safe state or can be operated ma-nually. When the mains voltage fails, the servo system then operates on battery voltage (DC voltage). In this case the operation and the function of the axis modules must be matched to battery operation (e. g. activation of the internal charging circuit in emergency operation).
Due to the lack of experience to date, a test is required on the specific application.
Supply via 2-pulse rectifier
There already exist practical applications in which the ECS axis modules are operated with a 2-pulse rectifier. However, this is a special case in which the original concept for the ECS devices series was not in the forefront.
On operation on the 2-pulse rectifier, various electrical and physical factors are of importance – e. g.:
- Voltage ripple on the DC bus – effect on drive behaviour
- Load on the DC bus capacitors – effect on the ageing of the axis modules
- Control performance
- Filtering measures
These parameters and their effects are described in detail in chapter 3.
The mains input fuse protection and the selection of the cable cross-sections are made in ac-cordance with applicable VDE regulations.
To protect the mains input, it is imperative that a varistor to suit the nominal mains voltage is used. (e. g. for 230 V mains: varistor type S20K250; for 400 V mains varistor type S20K460, for 480 V mains: varistor type S20K520)
The varistors must be installed on the AC side between the mains phases.
Supply from other drive controllers (8200; 9300)
In practice it is often the case that a specific product is provided by a feed drive and this product must then continue to be moved using a highly dynamic handling drive. In this constellation, a frequency inverter is often found as the line drive and an ECS axis module can be used as the handling drive. The operation of ECS drive modules on the DC output of the 9300, 8200 vector is in principle permissible. The overload capacity of the ECS axis modules is also to be taken into account here so that the mains input on the supplying device is not overloaded. In some circumstances the supplying device must be chosen larger so that the necessary ECS axis module overload can be covered.
DC fuses on the ECS:
Unlike the pure ECS servo system, on the operation of ECS axis modules on the DC bus with other device series, in some circumstances DC fuses must be provided between the supplying DC bus and ECS axis modules.
This fuse protection is always necessary if the supplying DC bus can output more than 40 A DC continuous current. Anyway it has to be executed in 2-poles (+Ug and -Ug).
Filter measures and mains chokes
Due to the design of the ECS servo system for three-phase supply, the filter measures are also correspondingly defined. The harmonic content in the mains voltage on single-phase supply is of course correspondingly greater, as on the B2 bridges all odd harmonics are present in the current and on the B6 bridges, ordinals that can be divided by three also disappear.
For this reason the filter for the ECS servo system is of only limited effect for a single-phase supply. If external filter measures are necessary due to customer requirements, a test must be made in the specific case.
For a supply via a standard B6 bridge, the standard ECS filter can be used. This filter is de-signed for a 10-axis system and therefore over-dimensioned for single axis applications. The ECS servo system chokes can be used for the mains choke. Particularly in single axis applica-tions, the voltage drop across the chokes must, however, also be taken into account (results in an additional speed limitation). On single-phase supply we therefore recommend the use of mains chokes only if there is sufficient DC bus capacitance of at least 800 µF/kW. Here the se-ries 8200 or 9300 mains chokes can be used. As a general figure for the voltage drop across the choke uk,set = 2 % applies.
The use of filters from the 8200 vector device series is not sensible due to the mechanical pa-rameters (footprint filters). We recommend making use of the standard components from known manufacturers (e. g.: Block or Schaffner) for the necessary filter measures and dimensioning these filters to suit the required mains current. An acceptance measurement on site at the ma-chine is necessary to ensure the measures are effective.
