4 Introduction
(Ask a Question)In a three-phase motor, the sum of three phase voltages or currents at any instant is equal to zero. Hence, it is sufficient to have only two currents or voltages to represent the motor behavior. However, the actual three-phase quantities are displaced by 120° and therefore, they are not completely decoupled. In order to decouple the two-phases that are used to represent the motor dynamics, Clarke transformation is applied to a, b, c phases to transform them to alpha–beta vectors. Clarke transform preserves the magnitude vectors while transforming them from three-phase a, b, c to two-phase alpha–beta. Similarly, inverse clarke transformation is used to convert alpha–beta to a, b, c components because the motor needs actual three-phase voltages to be applied to its stator terminals.
When the motor is rotating, alpha–beta quantities appear as sinusoidal quantities whose frequency depends on the speed of the motor and the number of motor poles. It is easier to control DC quantities than time-varying sinusoidal quantities, because of which, Park transformation is used to transform time-varying alpha–beta vectors to constant d–q vectors. This is called transforming from stator reference frame to rotor reference frame. After the d–q vectors are controlled to get the required motor dynamics, they have to be transformed back to stator reference frame using inverse park transformation.
Summary
(Ask a Question)| Core Version | This document applies to Field Oriented Control (FOC) Transformations v4.2. |
| Supported Device Families |
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| Supported Tool Flow | Requires Libero® SoC v11.8 or later releases. |
| Licensing | Complete encrypted RTL code is provided for the core, enabling the core to be instantiated with SmartDesign. Simulation, Synthesis, and Layout is performed with Libero software. FOC Transformations is licensed with encrypted RTL that must be purchased separately. For more information, see FOC Transformations. |
Features
(Ask a Question)FOC Transformations has the following key features:
- Computes clarke, inverse clarke, park, and inverse park transformations
- To reduce the resource count, only one math block is shared by all the transformations
Implementation of IP Core in Libero Design Suite
(Ask a Question)IP core must be installed to the IP Catalog of the Libero® SoC software. This is done automatically through the IP Catalog update function in the Libero SoC software, or the IP core can be manually downloaded from the catalog. Once the IP core is installed in the Libero SoC software IP Catalog, the core can be configured, generated, and instantiated within the SmartDesign tool for inclusion in the Libero project list.