Selecting the energy storageWARNING!ABB is not responsible for the energy storage selection or protection of the energystorage.The energy storage does not belong to the converter unit delivery. The customer (or thesystem integrator) must equip the DC/DC converter with a suitable energy storage system.The customer (or the system integrator) must also connect parallel modules (if any) to thesame energy storage. Additional guidelines:• Dimension the energy storage so that it withstands the required current cycles and thestored energy is sufficient. Take the depth of discharge into account in energy storagelifetime calculations.• Make sure that the energy storage withstands the current ripple of the converter. Seethe technical data.• The output voltage (energy storage voltage) is not allowed to exceed the DC/DCconverter DC bus voltage. Add sufficient voltage margin in the design to prevent this incase of voltage dips or grid faults.• The recommended energy storage operating voltage is:Ustorage = 150 V … 80% of UDC• Typical DC voltage values:• with diode supply units with modules (ACS880-304 +A003, ACS880-304 +A018):UDC = 1.35 × UAC• with IGBT supply units with modules (ACS880-204):UDC = 1.41 × UAC (can be changed with supply unit parameter group 123 DC voltref.• whereUDC = Drive DC voltage (in the DC bus)UAC = Drive input voltage (AC)• We recommend to measure the energy storage voltage. If the energy storage is a supercapacitor, voltage measurement is obligatory unless the capacitor withstands themaximum DC voltage of the drive or contains internal overvoltage protection.If the converter is equipped with the optional BAMU voltage/current measurement unit,the converter measures its output voltage (and thus also the energy storage voltage)automatically.If there is no BAMU, you must arrange the voltage measurement separately, and sendthe measured value to the converter control program, eg, via a fieldbus communication(if in use), or by some other means.For more information, see section Energy storage voltage measurement and estimationand parameter description in ACS880 DC/DC converter control program firmware manual(3AXD50000024671 [English]).• Equip the energy storage with a circuit breaker capable of opening the circuit if there isa failure in the energy storage or cable. See Selecting the protective circuit breaker ofthe energy storage and Energy storage disconnecting device.54 Guidelines for planning electrical installation
