Thank you, you are right, everything works well now.
The problem was I did not set all needed members of TIM_OC_InitTypeDef:
TIM_OC_InitTypeDef ocChannel;
ocChannel.OCMode = TIM_OCMODE_PWM1;
ocChannel.OCPolarity = TIM_OCPOLARITY_HIGH;
ocChannel.OCFastMode = TIM_OCFAST_DISABLE; //this one was missing
ocChannel.Pulse = 0;
As I found, it is masked to the CCMR register which had wrong value before: htim->Instance->CCMR1 |= sConfig->OCFastMode;
Thank you again for your help and time, Jiri