Power management in a network: Smart DC function for VP600 inverter and VP5000 DC/DC
For any electrical system with distributed power users and energy sources, power management of the overall system with dynamically changing loads is a challenge. For reasons of both reliability and real-time capability, SmartDC does not require bus communication. The SmartDC function works on the basis of the current HV voltage and intervenes within a few µs if necessary.
Requirement-based power supply
Controls the power supply of energy sources depending on the demand.
Ensures stability of the overall system
Limits the power of power users when necessary to ensure the stability of the overall system.
Real time
Works in µs real time on the basis of the HV voltage; CAN is not required for this but is “only” used to parameterize the function.
Description of the problem
In an efficiency-optimized system, the voltage level is allowed to fluctuate within a defined range. However, if the permissible fluctuation range is not complied with, this means that the power users in the system either have to be designed for a greater voltage range or they cannot generate their full output.
The challenge is to keep the voltage level in the DC link within the defined range. The optional Smart-DC function for the ARADEX VP600 and VP5000 devices can support you in this, so that an additional control often will be not necessary.
Common solutions without Smart DC function
Main requirement for power management:
High reliability/availability
Sufficiently fast reaction to external events
The special case described above as an example, where a HV battery switches off without warning at maximum recuperation power, must be intercepted. This can be achieved with a classic solution in the form of central control primarily by two alternatives, both of which, however, lead to greater complexity and higher series costs:
Installation of an extremely fast brake chopper and/or
Installation of significantly larger buffer capacitors to extend the required response time
The technological approach of SmartDC
ARADEX has the fast and reliable response of the FPGA-based controller board in both the VP600 and VP5000 with the SmartDC function. This allows a reaction to a too high or too low HV voltage within a few µs.
The basic concept of SmartDC is to use the HV voltage itself as a source of information about the behavior of each VP600 inverter or VP5000 DC/DC converter. Each power converter therefore reacts quickly and independently. No additional communication via CAN or similar is required. For applications with several power converters in a network, it is necessary to consider the entire system. This is then used to determine the parameters for optimally setting the SmartDC function in each device. This parameterization is then carried out once via CAN.
With SmartDC, even complex systems with several VP600 inverters and VP5000 DC/DC converters can be managed. The decentralized control of all components reduces the higher-level function in a vehicle control system to define the setpoints and monitoring the system.
Our team of project engineers will support you with regard to design and parameterization.
The testing is supported by our built-in oscilloscope functions (“Analyser”).(“ANALYSER”).